http://informahealthcare.com/xen ISSN: 0049-8254 (print), 1366-5928 (electronic) Xenobiotica, 2014; 44(10): 926–932 ! 2014 Informa UK Ltd. DOI: 10.3109/00498254.2014.901585
RESEARCH ARTICLE
Impact of genetic deficiencies of P-glycoprotein and breast cancer resistance protein on pharmacokinetics of aripiprazole and dehydroaripiprazole Yasuhisa Nagasaka1, Tomokazu Sano2, Kazuo Oda3, Akio Kawamura3, and Takashi Usui3 1
Analysis and Pharmacokinetics Research Labs, Astellas Pharma Inc., Ibaraki, Japan, 2ADME & Tox. Research Institute, Sekisui Medical Co., Ltd., Ibaraki, Japan, and 3Drug Metabolism Research Labs, Astellas Pharma Inc., Osaka, Japan
Abstract
Keywords
1. We investigated how deficiencies in P-glycoprotein (P-gp) and breast cancer resistance protein (BCRP) affect the pharmacokinetics of atypical antipsychotics aripiprazole and its active metabolite (dehydroaripiprazole) using normal Friend leukemia virus strain B (FVB) mice, BCRP knockout (Bcrp[/]) mice, and P-gp and BCRP triple knockout (Mdr1a/ 1b[/]Bcrp[/]) mice. 2. While plasma concentrations of aripiprazole and dehydroaripiprazole after oral administration were slightly higher in both Bcrp(/) and Mdr1a/1b(/)/Bcrp(/) mice than in normal FVB mice, the difference was not marked. The increase in absolute bioavailability (F) compared with normal mice (approximately 1.3-fold increase) was comparable between Bcrp(/) and Mdr1a/1b(/)/Bcrp(/) mice. This finding suggests that BCRP may be involved in the intestinal absorption of aripiprazole in mice, albeit with minimal contribution to absorption at best. 3. In contrast, the brain-to-plasma concentration ratio (Kp,brain) for aripiprazole and dehydroaripiprazole after oral administration was significantly higher in Mdr1a/1b(/ )/Bcrp(/) mice than in normal mice, whereas Bcrp(/) mice exhibited Kp,brain values similar to those in normal mice. In addition, the Kp,brain values in Mdr1a/1b(/)/Bcrp(/) mice were not drastically different from those previously reported in Mdr1a/1b(/) mice, suggesting that brain penetration of aripiprazole and dehydroaripiprazole can be affected by P-gp, but with little synergistic effect of BCRP.
Aripiprazole, brain penetration, breast cancer resistance protein, dehydroaripiprazole, knockout mouse, P-glycoprotein, mdr1a/1b, pharmacokinetics
Introduction Atypical antipsychotics have been widely used for the treatment of major mental illnesses such as schizophrenia and bipolar disorder. In clinical practice, the majority of atypical antipsychotics are not used alone but in combination with various types of drugs, including other antipsychotics (both typical and atypical antipsychotics) (Bleakley, 2012; Broekema et al., 2007; Langan & Shajahan, 2010). In addition, many therapeutic agents for the treatment of psychiatric disorders have relatively narrow therapeutic indices (Mitchell, 2000). To promote the appropriate use of atypical antipsychotics, it is therefore important to quantitatively assess the possibility of drug–drug interactions (DDIs) during combination therapy with antipsychotics or with atypical antipsychotics and drugs for other diseases.
Address for correspondence: Yasuhisa Nagasaka, Analysis and Pharmacokinetics Research Laboratories, Drug Discovery Research, Astellas Pharma Inc., 21 Miyukigaoka, Tsukuba, Ibaraki 305-8585, Japan. Tel: +81 298637151. Fax: +81 298525391. E-mail: [email protected]
History Received 24 January 2014 Revised 27 February 2014 Accepted 03 March 2014 Published online 26 March 2014
Although pharmaceutical companies and regulatory authorities previously focused on cytochrome P450-mediated DDIs, their attention has recently been drawn to the possibility of drug transporter-mediated DDIs (Giacomini et al., 2010). Of these transporters, P-glycoprotein (P-gp, MDR1; encoded by the mdr1a and mdr1b gene in mice) and breast cancer resistance protein (BCRP; encoded by the bcrp gene in mice) are major ATP-binding cassette efflux transporters expressed at the blood–brain barrier (BBB), which limit the entry of xenobiotics into the brain. Both transporters are also expressed in the luminal membrane of the small intestine and in the apical membrane of hepatocytes and kidney proximal tubules, and affect the absorption and elimination of various drugs. Studies have shown that several atypical antipsychotics (e.g. risperidone, paliperidone, amisulpride) are inhibitors and substrates for P-gp (Doran et al., 2005; Nakagami et al., 2005; Schmitt et al., 2006; Wang et al., 2006). In addition, a proportion of atypical antipsychotics can also inhibit BCRP activity (Wang et al., 2008), although none have been identified as a substrate for BCRP. Aripiprazole (Figure 1A) is a major atypical antipsychotic with a high affinity for dopamine D2 and D3 receptors, as well
P-gp/BCRP dysfunction and aripiprazole pharmacokinetics
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potential ‘‘cooperative role’’ of P-gp and BCRP in the central nervous system (CNS) distribution of aripiprazole and dehydroaripiprazole, in normal FVB mice, Bcrp(/) mice and Mdr1a/1b(/)/Bcrp(/) mice.
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Aripiprazole was purchased from Tokyo Chemical Industry Co., Ltd. (Tokyo, Japan) and dehydroaripiprazole from Toronto Research Chemicals Inc. (Toronto, ON, Canada). Papaverine was purchased from Cayman Chemical Company (Ann Arbor, MI). All other reagents and solutions were commercial products of analytical grade.
N N Cl Cl
Figure 1. The chemical structures of aripiprazole (A) dehydroaripiprazole, a major metabolite of aripiprazole (B).
and
as serotonin 5-HT1A, 5-HT2A and 5-HT2B receptors. This drug has a partial agonist activity against D2 receptors, which might help stabilize dopaminergic tone and improve both the negative and positive symptoms of schizophrenia (Burris et al., 2002). The major and active metabolite of aripiprazole, dehydroaripiprazole (Figure 1B), also has a high affinity for D2 receptors and exhibits pharmacological activities similar to those of aripiprazole (AbilifyTM tablets prescribing information). Aripiprazole and dehydroaripiprazole have been reported to be potent inhibitors of both P-gp and BCRP, and the possibility of intestinal DDIs involving these transporters and aripiprazole as a perpetrator cannot be ruled out (Nagasaka et al., 2012). Another study further demonstrated that the brain-to-plasma concentration ratio (Kp,brain) for aripiprazole and dehydroaripiprazole in Mdr1a/1b(/) mice after intraperitoneal administration was significantly higher than that in normal FVB mice, indicating that the two compounds are substrates for P-gp and that their brain penetration is limited by this transporter (Kirschbaum et al., 2010). No information, however, has yet been obtained on whether aripiprazole and dehydroaripiprazole are substrates for BCRP, and whether their pharmacokinetics is affected by defective BCRP function. Studies using Mdr1a/1b(/)/Bcrp(/) (P-gp/BCRP knockout) mice showed that the Kp,brain values of several anticancer drugs which are dual substrates for P-gp and BCRP were significantly higher in the absence of both transporter functions than the combined values of Kp,brain in the absence of each transporter alone. These findings suggest that P-gp and BCRP work cooperatively as gate keepers at the BBB, limiting the entry of the anticancer drugs (Agarwal et al., 2010; De Vries et al., 2007; Polli et al., 2009). Given that functional reduction of P-gp and BCRP due to genetic polymorphisms has been reported (Ieiri, 2012), functional changes in both transporters might occur and thereby significantly affect the pharmacokinetics of dual substrates in clinical practice. Here, we investigated how the genetic deficiencies of P-gp and BCRP affect the pharmacokinetics of aripiprazole and its active metabolite (dehydroaripiprazole), including the
Animals All the pharmacokinetic studies were performed in normal Friend leukemia virus strain B (FVB; wild-type), Bcrp(/) and Mdr1a/1b(/)/Bcrp(/) mice purchased from CLEA Japan, Inc. (Tokyo, Japan) and Taconic Farms Inc. (Germantown, NY). Mice were 7–8 weeks old at the time of aripiprazole administration. Animals were maintained under a 12-h light/dark cycle with unlimited access to food and water, and fasted from approximately 16 h before administration to 4 h after administration. All animal experiments were conducted with the approval of the animal experimental ethics committee of Astellas Pharma Inc. and Sekisui Medical Co., Ltd. Drug administration and sample collection Aripiprazole dosing solutions for intravenous (i.v.) and oral (p.o.) administration were prepared in dimethylsulfoxide, polyethylene glycol 400 and water (5:50:45, v/v/v) at a concentration of 0.4 mg/mL. For intravenous administration, normal FVB mice received a dose of 2 mg/kg via tail vein injection. The same dose (2 mg/kg) was also orally administered to normal, Bcrp knockout and triple-knockout mice. The animals were laparotomized under isoflurane anesthesia at the designated time point (i.v.: 0.1, 0.25, 0.5, 1, 2, 4, 8, 12, 24 and 48 h after the dose, p.o.: 0.25, 0.5, 1, 2, 4, 8, 12, 24 and 48 h after the dose; n ¼ 3 for each time point), and blood and brain were collected. Blood samples were obtained from the inferior vena cava using a heparinized syringe, then centrifuged at 8000g for 5 min at 4 C to obtain plasma, which was then stored at 20 C until analysis via liquid chromatography/tandem mass spectrometry (LC–MS/MS). The brain was removed from the skull and weighed, then homogenized with a 4-fold volume of phosphate buffered saline to obtain a 20% brain homogenate. Homogenate samples were also stored at 20 C until analysis. Determination of aripiprazole and dehydroaripiprazole concentrations in plasma and brain After intravenous or oral administration of aripiprazole, plasma and brain homogenate samples were pretreated with solid-phase extraction. Acetonitrile (50%) solution containing 0.1% formic acid solution containing 0.1% formic acid
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(solvent for standard solution; 20 lL) and papaverine solution (internal standard; 20 lL) were added to the plasma (20 lL) and brain homogenate (100 lL) samples. For calibration standard samples, 50% acetonitrile solution containing 0.1% formic acid, internal standard solution and standard solution (20 lL each) were added to blank plasma and brain homogenate. After adding 2% (v/v) phosphoric acid (0.4 mL) to these samples and stirring them for several seconds, the mixtures were centrifuged for 3 min at 4 C (10 000g). The supernatants were loaded onto an Oasis HLB lElution plate (30 lm) (Waters Corp., Milford, MA), which had been preconditioned with 0.2 mL of methanol and equilibrated with 0.2 mL of 2% (v/v) phosphoric acid, and the samples were extracted under reduced pressure. The plate was subsequently washed with 0.5 mL of 5% methanol, followed by drying using reduced pressure, and the samples were eluted with 0.2 mL of acetonitrile containing 1% formic acid into a 96-well polypropylene plate. After adding 0.2 mL of water and mixed with pipetting, a 2-mL aliquot of the solution was injected into the LC–MS/MS system, which consisted of a Shimadzu LC-20 HPLC (Shimadzu, Kyoto, Japan) coupled with a QTRAPÕ 5500 mass spectrometer (AB SCIEX, Framingham, MA). Chromatographic separation was performed using a Luna phenyl-hexyl column (3 mm, 2.0 mm 100 mm, Phenomenex, Milford, MA) under isocratic conditions with a mobile phase of acetonitrile/ 20 mmol/L ammonium acetate containing 0.1% formic acid/ water (60:40, v/v) at 40 C with a flow rate of 0.2 mL/min. For MS/MS analysis, multiple reaction monitoring (MRM) was conducted in positive ion mode by monitoring selected ions (precursor ion/product ion) for analytes (aripiprazole and dehydroaripiprazole) and internal standard (papaverine) as follows: aripiprazole (450.1/287.1), dehydroaripiprazole (446.0/285.0) and papaverine (340.0/324.0). The standard curves for aripiprazole and dehydroaripiprazole showed good linearity over the concentration ranges of 0.1–400 ng/mL for plasma and 0.1–400 ng/g for brain (the correction coefficient was >0.99). The deviation of each concentration backcalculated from the regression equation was 8.4% to 14.0% for the both analytes in plasma, and 10.0% to 10.5% in brain samples. For both aripiprazole and dehydroaripiprazole, the intra-assay coefficient of variation (CV) and relative error (RE) as determined at concentrations of 0.3, 15 and 300 ng/mL (plasma) or 0.3, 15 and 300 ng/g (brain) were within 15%, and those values at 0.1 ng/mL for plasma or 0.1 ng/g for brain samples (lower limit of quantification) were within 20%. Pharmacokinetic and statistical analysis Pharmacokinetic parameters of aripiprazole and dehydroaripiprazole after intravenous and oral administration to mice were calculated by non-compartmental analysis using Phoenix WinNonlin ver. 6.1 (Certara USA Inc., St. Louis, MO). The parameters were calculated using the mean plasma or brain concentrations of mice sacrificed at each time point. The maximum concentration (Cmax) and time to reach Cmax (Tmax) were observed values. Terminal elimination rate constant (l) was determined via least-square regression analysis of the terminal log-linear portion of the plasma or
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brain concentration-time profile, and the elimination half-life (t1/2) was calculated as 0.693/l. Area under the curve (AUC) extrapolated to infinity (AUCinf) was determined using the trapezoidal rule up to the last point (AUCt), and thereafter extrapolated to infinity based on l. The total body clearance (CLtot) was calculated as dose/AUCinf after intravenous administration. Distribution volume at the steady state (Vdss) was calculated by multiplying CLtot by MRTiv, where MRTiv is the mean residence time in plasma after intravenous dosing. The absolute bioavailability (F) in normal, Bcrp(/) and Mdr1a/1b(/)/Bcrp(/) mice was calculated from the ratio of AUCinf values after oral administration to these mice to those after intravenous administration to normal mice. Brain-to-plasma concentration ratios (Kp,brain) were calculated for each animal, and then the mean and standard deviation (SDs) of the ratios were calculated for each time point. Kp,brain in Bcrp(/) and Mdr1a/1b(/)/Bcrp(/) mice were compared with values in normal mice using Student’s twotailed t-test.
Results Plasma and brain concentrations in normal mice after intravenous administration After a single intravenous administration of aripiprazole to mice, plasma concentrations of aripiprazole decreased in a biphasic manner with an elimination half-life (t1/2) of 4.4 h (Figure 2, Table 1). The CLtot was 703 mL/h/kg and Vdss was 3770 mL/kg. Plasma concentrations of dehydroaripiprazole increased up to 8 h (Tmax) after administration of aripiprazole, then declined with a t1/2 of 4.9 h (Figure 2, Table 1). The timeprofiles of brain concentrations of both aripiprazole and dehydroaripiprazole were almost in parallel with those of the plasma concentrations. Plasma and brain concentrations in normal, Bcrp(/) and Mdr1a/1b(/)/Bcrp(/) mice after oral administration After a single oral administration to normal, Bcrp(/) and Mdr1a/1b(/)/Bcrp(/) mice, plasma concentrations of aripiprazole reached the maximum at 0.25 or 0.5 h, indicating relatively rapid absorption (Figure 3, Table 2). The plasma concentrations then declined with a t1/2 ranging from 4.1 to 4.6 h for each type of mouse. The Cmax values in Bcrp(/) and Mdr1a/1b(/)/Bcrp(/) mice were almost identical to those in normal mice. Although the AUCinf in these knockout mice was slightly higher than in normal mice, the difference was not marked (the ratio of AUCinf in both of the knockout mice to that in normal mice: 1.3). Absolute bioavailability (F) was 64% in normal mice, and 84% in both Bcrp(/) and Mdr1a/1b(/)/Bcrp(/) mice. In contrast, brain concentrations of aripiprazole in Mdr1a/1b(/)/Bcrp(/) mice were approximately 3- to 5-fold higher than those in normal mice, but concentrations in Bcrp(/) mice were comparable to values in normal mice (Figure 3, Table 2). As with aripiprazole, plasma dehydroaripiprazole concentrations in both Bcrp(/) and Mdr1a/1b(/)/Bcrp(/) mice were not drastically different from those in normal mice (the ratios of Cmax and AUCinf in Bcrp(/) to those in normal
Plasma or brain conc. (ng/mL or ng/g)
Figure 2. Plasma and brain concentration– time profiles of aripiprazole and dehydroaripiprazole after a single intravenous administration of aripiprazole to normal FVB mice at a dose of 2 mg/kg. Each point represents the mean ± SD of data from three mice.
10000
Plasma or brain conc. (ng/mL or ng/g)
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DOI: 10.3109/00498254.2014.901585
Aripiprazole
1000 Plasma Brain
100 10 1 0.1 0.01 0
6 12 18 24 30 36 42 48 54 Time (h)
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Dehydroaripiprazole
10000 1000
Plasma Brain
100 10 1 0.1 0.01
6 12 18 24 30 36 42 48 54 Time (h)
0
Table 1. Pharmacokinetic parameters of aripiprazole after a single intravenous administration of aripiprazole to normal FVB mice (2 mg/kg).
Compound Aripiprazole Dehydroaripiprazole
Specimen
CLtot (mL/h/kg)
Vdss (mL/kg)
Cmax (ng/mL or ng/g)
Tmax (h)
t1/2 (h)
AUCinf (ngh/mL or ngh/g)
Plasma Brain Plasma Brain
703 – – –
3770 – – –
– – 58.3 45.9
– – 8.0 4.0
4.4 4.1 4.9 3.8
2850 6550 987 680
Each parameter was calculated from the mean concentration–time profiles in plasma and brain. –, Not calculated.
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Normal Bcrp (-/-) Mdr1a/1b/Bcrp (-/-)
0.1
Brain
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Concentration (ng/mL)
Figure 3. Aripiprazole concentration–time profiles in plasma and brain after a single oral administration of aripiprazole (2 mg/kg) to normal, Bcrp knockout and Mdr1a/1b/ Bcrp knockout mice. Each point represents the mean ± SD of data from three mice.
100 10 1
Normal Bcrp (-/-) Mdr1a/1b/Bcrp (-/-)
0.1
0.01
0.01 0
6 12 18 24 30 36 42 48 54
0
Time (h)
6 12 18 24 30 36 42 48 54 Time (h)
Table 2. Pharmacokinetic parameters of aripiprazole and dehydroaripiprazole after a single oral administration of aripiprazole (2 mg/kg) to normal, Bcrp knockout and Mdr1a/1b/Bcrp knockout mice. Normal Compound Aripiprazole
Dehydroaripiprazole
Bcrp(/)
Mdr1a/1b(/)/Bcrp(/)
PK parameters
Plasma
Brain
Plasma
Brain
Plasma
Brain
Cmax (ng/mL or ng/g) Tmax (h) t1/2 (h) AUCinf (ng h/mL or ng h/g) F (%) Cmax (ng/mL or ng/g) Tmax (h) t1/2 (h) AUCinf (ng h/mL or ng h/g)
272 0.50 4.1 1810 64 60.1 8.0 4.4 950
751 0.50 4.5 3810 – 51.0 8.0 4.3 675
243 0.25 4.5 2400 84 84.0 8.0 4.5 1250
573 1.0 5.3 5400 – 55.7 8.0 4.2 821
304 0.50 4.6 2400 84 74.4 1.0 4.7 1310
2190 0.50 5.1 19 500 – 369 8.0 4.8 6220
Each parameter was calculated from the mean concentration–time profile in plasma and brain.
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mice: 1.4 and 1.3; corresponding ratios for Mdr1a/1b(/)/ Bcrp(/) mice: 1.2 and 1.4), whereas the brain concentrations in Mdr1a/1b(/)/Bcrp(/) mice were clearly higher than in normal mice (approximately 10-fold higher in the knockout mice on the AUCinf basis; Figure 4, Table 2). Brain to plasma concentration ratios (Kp, brain) in normal, Bcrp(/) and Mdr1a/1b(/)/ Bcrp(/) mice Based on the plasma and brain concentrations after oral administration, Kp,brain values of aripiprazole and dehydroaripiprazole were calculated and compared among normal, Bcrp(/) and Mdr1a/1b(/)/Bcrp(/) mice. The Kp,brain of aripiprazole in Mdr1a/1b(/)/Bcrp(/) mice was approximately 3.6-fold higher than in normal mice on average, while that in Bcrp(/) was comparable to values in normal mice (Table 3). The same was true for Kp,brain of dehydroaripiprazole, but the ratio of Kp,brain in Mdr1a/1b(/ )/Bcrp(/) mice to that in normal mice was higher for the metabolite, than the unchanged aripiprazole (ratio of Kp,brain in the knockout mice to that in normal mice was approximately 6.2; Table 3).
10000 Concentration (ng/mL)
Figure 4. Dehydroaripiprazole concentration– time profiles in plasma and brain after a single oral administration of aripiprazole (2 mg/kg) to normal, Bcrp knockout and Mdr1a/1b/Bcrp knockout mice. Each point represents the mean ± SD of data from three mice.
Discussion In the present study, we determine the plasma and brain concentrations of aripiprazole and dehydroaripiprazole after a single intravenous administration of aripiprazole in normal FVB mice, and compared values with those after a single oral administration were compared among normal, Bcrp(/) and Mdr1a/1b(/)/Bcrp(/) mice. As calculated from plasma concentrations after intravenous administration, the CLtot for aripiprazole in mice was 703 mL/h/kg and Vdss was 3770 mL/kg (Table 1), suggesting that aripiprazole has low clearance and a high volume of distribution in mice, considering reported values of hepatic blood flow and plasma volume (Davies & Morris, 1993). The pharmacokinetic characteristics of aripiprazole are also considered as possibly being similar between mice and humans, as various studies demonstrated that the compound showed low clearance (CLtot: 58.7 mL/ min) and relatively high volume of distribution (Vdss: 4.94 L/kg) in healthy male volunteers (Boulton et al., 2008; Mallikaarjun et al., 2004). In addition, time courses of aripiprazole and dehydroaripiprazole concentrations in the brain after a intravenous administration to normal mice were almost in parallel with those in plasma (Figure 2), suggesting 10000
Plasma
1000 100 10 1
Normal Bcrp (-/-) Mdr1a/1b/Bcrp (-/-)
0.1 0.01
Concentration (ng/g)
930
Brain
1000 100 10 1
Normal Bcrp (-/-) Mdr1a/1b/Bcrp (-/-)
0.1 0.01
0
6 12 18 24 30 36 42 48 54
0
6 12 18 24 30 36 42 48 54
Time (h)
Time (h)
Table 3. Brain to plasma concentration ratios (Kp, brain) of aripiprazole and dehydroaripiprazole after a single oral administration of aripiprazole (2 mg/kg) to normal, Bcrp knockout and Mdr1a/1b/Bcrp knockout mice. Aripiprazole Time (h) 0.25 0.5 1 2 4 8 12 24 48 Mean
Dehydroaripiprazole
Normal
Bcrp(/)
Mdr1a/1b(/)/Bcrp(/)
Normal
Bcrp(/)
Mdr1a/1b(/)/Bcrp(/)
1.33 ± 0.13 2.80 ± 0.44 2.15 ± 0.35 1.41 ± 0.56 2.06 ± 0.13 2.23 ± 0.04 2.19 ± 0.38 3.23 ± 0.22 3.90 ± 0.47 2.37
1.77 ± 0.46 (1.3) 2.03 ± 0.50 (0.7) 2.56 ± 0.48 (1.2) 2.71 ± 1.11 (1.9) 2.40 ± 0.37 (1.2) 1.97 ± 0.98 (0.9) 2.12 ± 0.35 (1.0) 2.75 ± 0.26 (0.9) 5.10 ± 0.65 (1.3) 2.60 (1.2)
3.87 ± 0.98* (2.9) 7.20 ± 0.99** (2.6) 7.41 ± 0.90*** (3.4) 8.17 ± 0.17*** (5.8) 8.08 ± 0.77*** (3.9) 9.18 ± 0.06*** (4.1) 8.46 ± 0.94*** (3.9) 6.60 ± 0.93** (2.0) 14.9 ± 3.65** (3.8) 8.21 (3.6)
0.31 ± 0.02 0.44 ± 0.05 0.49 ± 0.03 0.34 ± 0.16 0.63 ± 0.07 0.85 ± 0.04 0.77 ± 0.12 0.74 ± 0.02 0.91a 0.61
0.35 ± 0.01* (1.1) 0.42 ± 0.03 (1.0) 0.55 ± 0.03 (1.1) 0.58 ± 0.20 (1.7) 0.56 ± 0.11 (0.9) 0.68 ± 0.17 (0.8) 0.75 ± 0.14 (1.0) 0.73 ± 0.04 (1.0) 0.70 ± 0.08b (0.8) 0.59 (1.0)
1.24 ± 0.39* (4.0) 1.70 ± 0.36** (3.9) 2.56 ± 0.65** (5.2) 3.33 ± 0.68** (9.8) 4.56 ± 0.13*** (7.3) 5.31 ± 0.22*** (6.2) 5.69 ± 0.15*** (7.4) 3.83 ± 0.57*** (5.2) 6.38 ± 1.91b (7.0) 3.84 (6.2)
Data are presented as mean ± SD from three mice at each time point. Values in parentheses represent the ratios of Kp,brain (mean) in respective knockout mice to that in normal FVB mice. a Mean of two mice. b Statistical analysis was not performed for the Kp,values at 48 h because only two mice data were available for normal mice. *Versus normal, p50.05. **Versus normal, p50.01. ***Versus normal, p50.001.
DOI: 10.3109/00498254.2014.901585
that both compounds rapidly reached equilibrium between the plasma and brain. In the three types of mice examined here, plasma concentrations of aripiprazole after oral administration decreased with similar t1/2 values (approximately 4–5 h), which were also comparable to values after intravenous administration to normal mice (4.4 h) (Figure 3, Table 2). In general, the t1/2 of a drug can be expressed as 0.693 Vd/ CLtot. Accordingly, possible reasons that t1/2 values were similar among normal, Bcrp(/), and Mdr1a/1b(/)/ Bcrp(/) mice are (1) both Vd and CLtot were comparable among the three types of mice, (2) both Vd and CLtot increased or decreased in parallel and to a similar extent in Bcrp(/), and/or Mdr1a/1b(/)/Bcrp(/) mice. Meanwhile, P-gp and BCRP not only pump out drugs from the tissues such as brain or testes, but are also involved in the excretion of drugs from the liver or kidney. Thus, the dysfunction of these transporters may increase Vd for substrate drugs by enhancing distribution into tissues and/or decrease CLtot by reducing excretion, while CLtot and Vd are unlikely to change in the same direction. We therefore consider genetic deficiencies in both P-gp and BCRP to have almost no effect on either Vd or CLtot of aripiprazole in mice. In contrast, AUCinf for plasma and the resulting F values in Bcrp(/) and Mdr1a/1b(/)/Bcrp(/) mice were slightly higher than in normal mice, but the difference was not marked (approximately 1.3-fold higher in the knockout mice than in normal mice; Table 2). F can be expressed as Fa Fg Fh, where Fa denotes fraction absorbed, Fg intestinal availability and Fh hepatic availability. Fh can be described as 1 CLh/Qh, where CLh denotes hepatic clearance and Qh hepatic blood flow. Given that the CLtot for aripiprazole in mice was low as previously suggested, Fh is unlikely to increase even if biliary excretion of the unchanged drug is involved in the elimination of the compound in mice to some extent. In addition, there is generally little likelihood that the defect in P-gp and/or BCRP would lead to any decrease in the activities of intestinal and/or hepatic metabolism (increase in Fg and Fh) of a compound. Taken together, these present findings suggest that any slight increase in the absolute bioavailability (F) of this compound in Bcrp(/) and Mdr1a/1b(/)/Bcrp(/) mice is mainly due to the increase in Fa. Further, the extent of the bioavailability increase was comparable between the two knockout mouse strains, suggesting that BCRP rather than P-gp may make some minimal contribution, to the intestinal absorption of aripiprazole in mice. In humans, the involvement of BCRP in intestinal absorption is of little concern, as the absolute bioavailability in humans is reported to be 87% (AbilifyTM tablets prescribing information), which is even higher than that in mice in the present study (64%). As with aripiprazole, plasma concentrations of dehydroaripiprazole in Bcrp(/) and Mdr1a/1b(/)/Bcrp(/) mice were not markedly higher than those in normal mice. The ratio of AUCinf in these knockout mice to that in normal mice ranged from approximately 1.3 to 1.4, which is comparable to the corresponding ratio for aripiprazole. Further, the t1/2 values for dehydroaripiprazole were similar among normal, Bcrp(/) and Mdr1a/1b(/)/Bcrp(/) mice (Figure 4, Table 2). These results suggest that
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deficiencies in these drug transporters also had little or almost no effect on the elimination (e.g. hepatic metabolism and/or biliary excretion, if any) of the metabolite, and that the slight increase in plasma concentrations in Bcrp(/) and Mdr1a/1b(/)/Bcrp(/) mice was largely due to the increase in unchanged aripiprazole concentrations. Brain concentrations of aripiprazole in Bcrp(/) mice were not significantly higher than in normal mice, with levels expected from the increase of plasma concentrations in the knockout mice. In contrast, Mdr1a/1b(/)/Bcrp(/) mice showed distinctly higher concentrations in the brain (knockout/normal AUCinf ratio: approximately 5; Table 2). The same was true for brain concentrations of dehydroaripiprazole, but this increasing tendency was more marked for this metabolite (knockout/normal AUCinf ratio: approximately 10; Table 2). The resulting Kp,brain values for aripiprazole and dehydroaripiprazole were comparable between normal and Bcrp(/) mice, while those in Mdr1a/1b(/)/Bcrp(/) mice were approximately 3.6- and 6.2-fold higher than in normal mice on average, respectively (Table 3). In several studies on the comparison of CNS penetration of various drugs among Mdr1a/1b(/)/Bcrp(/), and Mdr1a/1b(/)/Bcrp(/) mice, a number of drugs – such as erlotinib, lapatinib and GDC-0941 – showed a more than 10-fold increase in Kp,brain in Mdr1a/1b(/)/Bcrp(/) mice, compared with the normal (wild-type) mice, in the absence of a marked change in the defect of each transporter (Kodaira et al., 2010; Polli et al., 2009; Salphati et al., 2010). This cooperative role of P-gp and BCRP on the restriction of CNS penetration of dual substrates can be explained by their contribution to the net efflux at the BBB, as Kodaira et al. (2010) demonstrated using the following equations to describe the ratio of Kp (R) in Mdr1a/ 1b(/)/Bcrp(/), and Mdr1a/1b(/)/Bcrp(/) mice to that in normal FVB mice, respectively: RMdr1a=1bð=Þ ¼ 1 þ
RBcrpð=Þ ¼ 1 þ
PSPgp ; PSeff þ PSBcrp
PSBcrp ; PSeff þ PSPgp
RMdr1a=1bð=ÞBcrpð=Þ ¼ 1 þ
PSPgp þ PSBcrp ; PSeff
ð1Þ
ð2Þ
ð3Þ
where PSeff denotes the permeability surface area (PS) products for the passive diffusion, PSP-gp the active efflux mediated by P-gp on the blood-side membrane of endothelial cells in the brain and PSBcrp the active efflux mediated by Bcrp on the blood-side membrane of endothelial cells in the brain. For drugs with similar affinity for both P-gp and BCRP, P-gp plays a dominant role in the drug efflux from the brain, as P-gp protein levels are higher than those of BCRP at the mouse BBB. Consequently, RMdr1a/1b(/) is slightly larger than 1 and RBcrp(/) is less than RMdr1a/1b(/) or almost equal to 1, whereas RMdr1a/1b(/)/Bcrp(/) is markedly higher than 1 and even more than the combined levels from knockout mice for each transporter, as explained by the equations shown above and summarized by Agarwal et al. (2011).
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In contrast, the RMdr1a/1b(/)/Bcrp(/) values for aripiprazole and dehydroaripiprazole estimated in the present study were slightly higher than but not drastically different from the RMdr1a/1b(/) previously indicated (approximately 2–3 for aripiprazole and approximately 4 for dehydroaripiprazole) (Kirschbaum et al., 2010; Wang et al., 2009) and the RBcrp(/ ) was almost close to unity, implying that these two compounds have higher affinity for P-gp than BCRP, resulting in substantial contribution of P-gp on their CNS penetration with little impact of BCRP, in contrast to the intestinal absorption. Given that the intestinal concentrations of drugs are generally considered to be much higher than systemic concentrations, the efflux of aripiprazole mediated by P-gp might be saturated in intestinal absorption, whereas efflux mediated by BCRP might still affect the absorption of aripiprazole to some extent due to its lower affinity. At present, however, we have no information on the Km values of aripiprzole for these transporters, and further investigation is required to clarify the reason for the contrasting observations on the contribution of BCRP between intestinal absorption and CNS penetration. Of additional note, the brain disposition of aripiprazole and dehydroaripiprazole in schizophrenia patients with P-gp genetic polymorphisms may differ markedly from disposition in P-gp normal patients, as several single nucleotide polymorphisms (SNPs) in the MDR1 gene – especially 3435C>T (rs1045642, exon 26) and 2677G>T/A (rs2032582, exon 21) – may alter P-gp expression levels in human tissues (Hemauer et al., 2010; Hoffmeyer et al., 2000). In conclusion, plasma concentrations of aripiprazole and dehydroaripiprazole after oral administration of aripiprazole to mice were not greatly affected by the dysfunction of both Pgp and BCRP. In addition, brain penetration of aripiprazole and dehydroaripiprazole might be affected by P-gp function, but with little synergistic influence from BCRP.
Acknowledgements The authors thank Masafumi Furukawa, Hisako Naito, Hiroyuki Chijiwa, Mitsunari Suzuki, Tomoko Numata, Kazumi Ichige, Kumiko Takei and Takayuki Miyake (ADME & Tox. Research Institute, Sekisui Medical Co., Ltd.) for their contribution to the animal experiments.
Declaration of interest The authors report no conflicts of interest.
References Agarwal S, Hartz AM, Elmquist WF, Bauer B. (2011). Breast cancer resistance protein and P-glycoprotein in brain cancer: two gatekeepers team up. Curr Pharm Des 17:2793–802. Agarwal S, Sane R, Gallardo JL, et al. (2010). Distribution of gefitinib to the brain is limited by P-glycoprotein (ABCB1) and breast cancer resistance protein (ABCG2)-mediated active efflux. J Pharmacol Exp Ther 334:147–55. Bleakley S. (2012). Identifying and reducing the risk of antipsychotic drug interactions. Progr Neurol Psychiatry 16:20–4. Boulton DW, Kollia G, Mallikaarjun S, et al. (2008). Pharmacokinetics and tolerability of intramuscular, oral and intravenous aripiprazole in healthy subjects and in patients with schizophrenia. Clin Pharmacokinet 47:475–85. Bristol-Myers Squibb Company and Otsuka America Pharmaceutical Inc. AbilifyTM (aripiprazole) tablets prescribing information. Available at: http://www.abilify.com
Xenobiotica, 2014; 44(10): 926–932
Broekema WJ, De Groot IW, Van Harten PN. (2007). Simultaneous prescribing of atypical antipsychotics, conventional antipsychotics and anticholinergics—a European study. Pharm World Sci 29:126–30. Burris KD, Molski TF, Xu C, et al. (2002). Aripiprazole, a novel antipsychotic, is a high-affinity partial agonist at human dopamine D2 receptors. J Pharmacol Exp Ther 302:381–9. Davies B, Morris T. (1993). Physiological parameters in laboratory animals and humans. Pharm Res 10:1093–5. De Vries NA, Zhao J, Kroon E, et al. (2007). P-glycoprotein and breast cancer resistance protein: two dominant transporters working together in limiting the brain penetration of topotecan. Clin Cancer Res 13: 6440–9. Doran A, Obach RS, Smith BJ, et al. (2005). The impact of P-glycoprotein on the disposition of drugs targeted for indications of the central nervous system: evaluation using the MDR1A/1B knockout mouse model. Drug Metab Dispos 33:165–74. Giacomini KM, Huang SM, Tweedie DJ, et al. (2010). Membrane transporters in drug development. Nat Rev Drug Discov 9:215–36. Hemauer SJ, Nanovskaya TN, Abdel-Rahman SZ, et al. (2010). Modulation of human placental P-glycoprotein expression and activity by MDR1 gene polymorphisms. Biochem Pharmacol 79:921–5. Hoffmeyer S, Burk O, Von Richter O, et al. (2000). Functional polymorphisms of the human multidrug-resistance gene: multiple sequence variations and correlation of one allele with P-glycoprotein expression and activity in vivo. Proc Natl Acad Sci USA 97:3473–8. Ieiri I. (2012). Functional significance of genetic polymorphisms in P-glycoprotein (MDR1, ABCB1) and breast cancer resistance protein (BCRP, ABCG2). Drug Metab Pharmacokinet 27:85–105. Kirschbaum KM, Uhr M, Holthoewer D, et al. (2010). Pharmacokinetics of acute and sub-chronic aripiprazole in P-glycoprotein deficient mice. Neuropharmacology 59:474–9. Kodaira H, Kusuhara H, Ushiki J, et al. (2010). Kinetic analysis of the cooperation of P-glycoprotein (P-gp/Abcb1) and breast cancer resistance protein (Bcrp/Abcg2) in limiting the brain and testis penetration of erlotinib, flavopiridol, and mitoxantrone. J Pharmacol Exp Ther 333:788–96. Langan J, Shajahan P. (2010). Antipsychotic polypharmacy: review of mechanisms, mortality and management. The Psychiatrist 34: 58–62. Mallikaarjun S, Salazar DE, Bramer SL. (2004). Pharmacokinetics, tolerability, and safety of aripiprazole following multiple oral dosing in normal healthy volunteers. J Clin Pharmacol 44:179–87. Mitchell P. (2000). Therapeutic drug monitoring of psychotropic medications. Br J Clin Pharmacol 49:303–12. Nagasaka Y, Oda K, Iwatsubo T, et al. (2012). Effects of aripiprazole and its active metabolite dehydroaripiprazole on the activities of drug efflux transporters expressed both in the intestine and at the blood– brain barrier. Biopharm Drug Dispos 33:304–15. Nakagami T, Yasui-Furukori N, Saito M, et al. (2005). Effect of verapamil on pharmacokinetics and pharmacodynamics of risperidone: in vivo evidence of involvement of P-glycoprotein in risperidone disposition. Clin Pharmacol Ther 78:43–51. Polli JW, Olson KL, Chism JP, et al. (2009). An unexpected synergist role of P-glycoprotein and breast cancer resistance protein on the central nervous system penetration of the tyrosine kinase inhibitor lapatinib (N-{3-chloro-4-[(3-fluorobenzyl)oxy]phenyl}-6-[5-({[2(methylsulfonyl)ethyl]amino}methyl)-2-furyl]-4-quinazolinamine; GW572016). Drug Metab Dispos 37:439–42. Salphati L, Lee LB, Pang J, et al. (2010). Role of P-glycoprotein and breast cancer resistance protein-1 in the brain penetration and brain pharmacodynamic activity of the novel phosphatidylinositol 3-kinase inhibitor GDC-0941. Drug Metab Dispos 38:1422–6. Schmitt U, Abou El-Ela A, Guo LJ, et al. (2006). Cyclosporine A (CsA) affects the pharmacodynamics and pharmacokinetics of the atypical antipsychotic amisulpride probably via inhibition of P-glycoprotein (P-gp). J Neural Transm 113:787–801. Wang J, Zhu H, Markowitz J, et al. (2008). Antipsychotic drugs inhibit the function of breast cancer resistance protein. Basic Clin Pharmacol Toxicol 103:336–41. Wang JS, Zhu HJ, Donovan JL, et al. (2009). Aripiprazole brain concentration is altered in P-glycoprotein deficient mice. Schizophr Res 110:90–4. Wang JS, Zhu HJ, Markowitz JS, et al. (2006). Evaluation of antipsychotic drugs as inhibitors of multidrug resistance transporter P-glycoprotein. Psychopharmacology (Berl) 187:415–23.
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RESEARCH ARTICLE
Impact of genetic deficiencies of P-glycoprotein and breast cancer resistance protein on pharmacokinetics of aripiprazole and dehydroaripiprazole Yasuhisa Nagasaka1, Tomokazu Sano2, Kazuo Oda3, Akio Kawamura3, and Takashi Usui3 1
Analysis and Pharmacokinetics Research Labs, Astellas Pharma Inc., Ibaraki, Japan, 2ADME & Tox. Research Institute, Sekisui Medical Co., Ltd., Ibaraki, Japan, and 3Drug Metabolism Research Labs, Astellas Pharma Inc., Osaka, Japan
Abstract
Keywords
1. We investigated how deficiencies in P-glycoprotein (P-gp) and breast cancer resistance protein (BCRP) affect the pharmacokinetics of atypical antipsychotics aripiprazole and its active metabolite (dehydroaripiprazole) using normal Friend leukemia virus strain B (FVB) mice, BCRP knockout (Bcrp[/]) mice, and P-gp and BCRP triple knockout (Mdr1a/ 1b[/]Bcrp[/]) mice. 2. While plasma concentrations of aripiprazole and dehydroaripiprazole after oral administration were slightly higher in both Bcrp(/) and Mdr1a/1b(/)/Bcrp(/) mice than in normal FVB mice, the difference was not marked. The increase in absolute bioavailability (F) compared with normal mice (approximately 1.3-fold increase) was comparable between Bcrp(/) and Mdr1a/1b(/)/Bcrp(/) mice. This finding suggests that BCRP may be involved in the intestinal absorption of aripiprazole in mice, albeit with minimal contribution to absorption at best. 3. In contrast, the brain-to-plasma concentration ratio (Kp,brain) for aripiprazole and dehydroaripiprazole after oral administration was significantly higher in Mdr1a/1b(/ )/Bcrp(/) mice than in normal mice, whereas Bcrp(/) mice exhibited Kp,brain values similar to those in normal mice. In addition, the Kp,brain values in Mdr1a/1b(/)/Bcrp(/) mice were not drastically different from those previously reported in Mdr1a/1b(/) mice, suggesting that brain penetration of aripiprazole and dehydroaripiprazole can be affected by P-gp, but with little synergistic effect of BCRP.
Aripiprazole, brain penetration, breast cancer resistance protein, dehydroaripiprazole, knockout mouse, P-glycoprotein, mdr1a/1b, pharmacokinetics
Introduction Atypical antipsychotics have been widely used for the treatment of major mental illnesses such as schizophrenia and bipolar disorder. In clinical practice, the majority of atypical antipsychotics are not used alone but in combination with various types of drugs, including other antipsychotics (both typical and atypical antipsychotics) (Bleakley, 2012; Broekema et al., 2007; Langan & Shajahan, 2010). In addition, many therapeutic agents for the treatment of psychiatric disorders have relatively narrow therapeutic indices (Mitchell, 2000). To promote the appropriate use of atypical antipsychotics, it is therefore important to quantitatively assess the possibility of drug–drug interactions (DDIs) during combination therapy with antipsychotics or with atypical antipsychotics and drugs for other diseases.
Address for correspondence: Yasuhisa Nagasaka, Analysis and Pharmacokinetics Research Laboratories, Drug Discovery Research, Astellas Pharma Inc., 21 Miyukigaoka, Tsukuba, Ibaraki 305-8585, Japan. Tel: +81 298637151. Fax: +81 298525391. E-mail: [email protected]
History Received 24 January 2014 Revised 27 February 2014 Accepted 03 March 2014 Published online 26 March 2014
Although pharmaceutical companies and regulatory authorities previously focused on cytochrome P450-mediated DDIs, their attention has recently been drawn to the possibility of drug transporter-mediated DDIs (Giacomini et al., 2010). Of these transporters, P-glycoprotein (P-gp, MDR1; encoded by the mdr1a and mdr1b gene in mice) and breast cancer resistance protein (BCRP; encoded by the bcrp gene in mice) are major ATP-binding cassette efflux transporters expressed at the blood–brain barrier (BBB), which limit the entry of xenobiotics into the brain. Both transporters are also expressed in the luminal membrane of the small intestine and in the apical membrane of hepatocytes and kidney proximal tubules, and affect the absorption and elimination of various drugs. Studies have shown that several atypical antipsychotics (e.g. risperidone, paliperidone, amisulpride) are inhibitors and substrates for P-gp (Doran et al., 2005; Nakagami et al., 2005; Schmitt et al., 2006; Wang et al., 2006). In addition, a proportion of atypical antipsychotics can also inhibit BCRP activity (Wang et al., 2008), although none have been identified as a substrate for BCRP. Aripiprazole (Figure 1A) is a major atypical antipsychotic with a high affinity for dopamine D2 and D3 receptors, as well
P-gp/BCRP dysfunction and aripiprazole pharmacokinetics
DOI: 10.3109/00498254.2014.901585
(A)
O
H N
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potential ‘‘cooperative role’’ of P-gp and BCRP in the central nervous system (CNS) distribution of aripiprazole and dehydroaripiprazole, in normal FVB mice, Bcrp(/) mice and Mdr1a/1b(/)/Bcrp(/) mice.
O
N N Cl
Materials and methods
Cl
Chemicals O
(B)
H N
O
Aripiprazole was purchased from Tokyo Chemical Industry Co., Ltd. (Tokyo, Japan) and dehydroaripiprazole from Toronto Research Chemicals Inc. (Toronto, ON, Canada). Papaverine was purchased from Cayman Chemical Company (Ann Arbor, MI). All other reagents and solutions were commercial products of analytical grade.
N N Cl Cl
Figure 1. The chemical structures of aripiprazole (A) dehydroaripiprazole, a major metabolite of aripiprazole (B).
and
as serotonin 5-HT1A, 5-HT2A and 5-HT2B receptors. This drug has a partial agonist activity against D2 receptors, which might help stabilize dopaminergic tone and improve both the negative and positive symptoms of schizophrenia (Burris et al., 2002). The major and active metabolite of aripiprazole, dehydroaripiprazole (Figure 1B), also has a high affinity for D2 receptors and exhibits pharmacological activities similar to those of aripiprazole (AbilifyTM tablets prescribing information). Aripiprazole and dehydroaripiprazole have been reported to be potent inhibitors of both P-gp and BCRP, and the possibility of intestinal DDIs involving these transporters and aripiprazole as a perpetrator cannot be ruled out (Nagasaka et al., 2012). Another study further demonstrated that the brain-to-plasma concentration ratio (Kp,brain) for aripiprazole and dehydroaripiprazole in Mdr1a/1b(/) mice after intraperitoneal administration was significantly higher than that in normal FVB mice, indicating that the two compounds are substrates for P-gp and that their brain penetration is limited by this transporter (Kirschbaum et al., 2010). No information, however, has yet been obtained on whether aripiprazole and dehydroaripiprazole are substrates for BCRP, and whether their pharmacokinetics is affected by defective BCRP function. Studies using Mdr1a/1b(/)/Bcrp(/) (P-gp/BCRP knockout) mice showed that the Kp,brain values of several anticancer drugs which are dual substrates for P-gp and BCRP were significantly higher in the absence of both transporter functions than the combined values of Kp,brain in the absence of each transporter alone. These findings suggest that P-gp and BCRP work cooperatively as gate keepers at the BBB, limiting the entry of the anticancer drugs (Agarwal et al., 2010; De Vries et al., 2007; Polli et al., 2009). Given that functional reduction of P-gp and BCRP due to genetic polymorphisms has been reported (Ieiri, 2012), functional changes in both transporters might occur and thereby significantly affect the pharmacokinetics of dual substrates in clinical practice. Here, we investigated how the genetic deficiencies of P-gp and BCRP affect the pharmacokinetics of aripiprazole and its active metabolite (dehydroaripiprazole), including the
Animals All the pharmacokinetic studies were performed in normal Friend leukemia virus strain B (FVB; wild-type), Bcrp(/) and Mdr1a/1b(/)/Bcrp(/) mice purchased from CLEA Japan, Inc. (Tokyo, Japan) and Taconic Farms Inc. (Germantown, NY). Mice were 7–8 weeks old at the time of aripiprazole administration. Animals were maintained under a 12-h light/dark cycle with unlimited access to food and water, and fasted from approximately 16 h before administration to 4 h after administration. All animal experiments were conducted with the approval of the animal experimental ethics committee of Astellas Pharma Inc. and Sekisui Medical Co., Ltd. Drug administration and sample collection Aripiprazole dosing solutions for intravenous (i.v.) and oral (p.o.) administration were prepared in dimethylsulfoxide, polyethylene glycol 400 and water (5:50:45, v/v/v) at a concentration of 0.4 mg/mL. For intravenous administration, normal FVB mice received a dose of 2 mg/kg via tail vein injection. The same dose (2 mg/kg) was also orally administered to normal, Bcrp knockout and triple-knockout mice. The animals were laparotomized under isoflurane anesthesia at the designated time point (i.v.: 0.1, 0.25, 0.5, 1, 2, 4, 8, 12, 24 and 48 h after the dose, p.o.: 0.25, 0.5, 1, 2, 4, 8, 12, 24 and 48 h after the dose; n ¼ 3 for each time point), and blood and brain were collected. Blood samples were obtained from the inferior vena cava using a heparinized syringe, then centrifuged at 8000g for 5 min at 4 C to obtain plasma, which was then stored at 20 C until analysis via liquid chromatography/tandem mass spectrometry (LC–MS/MS). The brain was removed from the skull and weighed, then homogenized with a 4-fold volume of phosphate buffered saline to obtain a 20% brain homogenate. Homogenate samples were also stored at 20 C until analysis. Determination of aripiprazole and dehydroaripiprazole concentrations in plasma and brain After intravenous or oral administration of aripiprazole, plasma and brain homogenate samples were pretreated with solid-phase extraction. Acetonitrile (50%) solution containing 0.1% formic acid solution containing 0.1% formic acid
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(solvent for standard solution; 20 lL) and papaverine solution (internal standard; 20 lL) were added to the plasma (20 lL) and brain homogenate (100 lL) samples. For calibration standard samples, 50% acetonitrile solution containing 0.1% formic acid, internal standard solution and standard solution (20 lL each) were added to blank plasma and brain homogenate. After adding 2% (v/v) phosphoric acid (0.4 mL) to these samples and stirring them for several seconds, the mixtures were centrifuged for 3 min at 4 C (10 000g). The supernatants were loaded onto an Oasis HLB lElution plate (30 lm) (Waters Corp., Milford, MA), which had been preconditioned with 0.2 mL of methanol and equilibrated with 0.2 mL of 2% (v/v) phosphoric acid, and the samples were extracted under reduced pressure. The plate was subsequently washed with 0.5 mL of 5% methanol, followed by drying using reduced pressure, and the samples were eluted with 0.2 mL of acetonitrile containing 1% formic acid into a 96-well polypropylene plate. After adding 0.2 mL of water and mixed with pipetting, a 2-mL aliquot of the solution was injected into the LC–MS/MS system, which consisted of a Shimadzu LC-20 HPLC (Shimadzu, Kyoto, Japan) coupled with a QTRAPÕ 5500 mass spectrometer (AB SCIEX, Framingham, MA). Chromatographic separation was performed using a Luna phenyl-hexyl column (3 mm, 2.0 mm 100 mm, Phenomenex, Milford, MA) under isocratic conditions with a mobile phase of acetonitrile/ 20 mmol/L ammonium acetate containing 0.1% formic acid/ water (60:40, v/v) at 40 C with a flow rate of 0.2 mL/min. For MS/MS analysis, multiple reaction monitoring (MRM) was conducted in positive ion mode by monitoring selected ions (precursor ion/product ion) for analytes (aripiprazole and dehydroaripiprazole) and internal standard (papaverine) as follows: aripiprazole (450.1/287.1), dehydroaripiprazole (446.0/285.0) and papaverine (340.0/324.0). The standard curves for aripiprazole and dehydroaripiprazole showed good linearity over the concentration ranges of 0.1–400 ng/mL for plasma and 0.1–400 ng/g for brain (the correction coefficient was >0.99). The deviation of each concentration backcalculated from the regression equation was 8.4% to 14.0% for the both analytes in plasma, and 10.0% to 10.5% in brain samples. For both aripiprazole and dehydroaripiprazole, the intra-assay coefficient of variation (CV) and relative error (RE) as determined at concentrations of 0.3, 15 and 300 ng/mL (plasma) or 0.3, 15 and 300 ng/g (brain) were within 15%, and those values at 0.1 ng/mL for plasma or 0.1 ng/g for brain samples (lower limit of quantification) were within 20%. Pharmacokinetic and statistical analysis Pharmacokinetic parameters of aripiprazole and dehydroaripiprazole after intravenous and oral administration to mice were calculated by non-compartmental analysis using Phoenix WinNonlin ver. 6.1 (Certara USA Inc., St. Louis, MO). The parameters were calculated using the mean plasma or brain concentrations of mice sacrificed at each time point. The maximum concentration (Cmax) and time to reach Cmax (Tmax) were observed values. Terminal elimination rate constant (l) was determined via least-square regression analysis of the terminal log-linear portion of the plasma or
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brain concentration-time profile, and the elimination half-life (t1/2) was calculated as 0.693/l. Area under the curve (AUC) extrapolated to infinity (AUCinf) was determined using the trapezoidal rule up to the last point (AUCt), and thereafter extrapolated to infinity based on l. The total body clearance (CLtot) was calculated as dose/AUCinf after intravenous administration. Distribution volume at the steady state (Vdss) was calculated by multiplying CLtot by MRTiv, where MRTiv is the mean residence time in plasma after intravenous dosing. The absolute bioavailability (F) in normal, Bcrp(/) and Mdr1a/1b(/)/Bcrp(/) mice was calculated from the ratio of AUCinf values after oral administration to these mice to those after intravenous administration to normal mice. Brain-to-plasma concentration ratios (Kp,brain) were calculated for each animal, and then the mean and standard deviation (SDs) of the ratios were calculated for each time point. Kp,brain in Bcrp(/) and Mdr1a/1b(/)/Bcrp(/) mice were compared with values in normal mice using Student’s twotailed t-test.
Results Plasma and brain concentrations in normal mice after intravenous administration After a single intravenous administration of aripiprazole to mice, plasma concentrations of aripiprazole decreased in a biphasic manner with an elimination half-life (t1/2) of 4.4 h (Figure 2, Table 1). The CLtot was 703 mL/h/kg and Vdss was 3770 mL/kg. Plasma concentrations of dehydroaripiprazole increased up to 8 h (Tmax) after administration of aripiprazole, then declined with a t1/2 of 4.9 h (Figure 2, Table 1). The timeprofiles of brain concentrations of both aripiprazole and dehydroaripiprazole were almost in parallel with those of the plasma concentrations. Plasma and brain concentrations in normal, Bcrp(/) and Mdr1a/1b(/)/Bcrp(/) mice after oral administration After a single oral administration to normal, Bcrp(/) and Mdr1a/1b(/)/Bcrp(/) mice, plasma concentrations of aripiprazole reached the maximum at 0.25 or 0.5 h, indicating relatively rapid absorption (Figure 3, Table 2). The plasma concentrations then declined with a t1/2 ranging from 4.1 to 4.6 h for each type of mouse. The Cmax values in Bcrp(/) and Mdr1a/1b(/)/Bcrp(/) mice were almost identical to those in normal mice. Although the AUCinf in these knockout mice was slightly higher than in normal mice, the difference was not marked (the ratio of AUCinf in both of the knockout mice to that in normal mice: 1.3). Absolute bioavailability (F) was 64% in normal mice, and 84% in both Bcrp(/) and Mdr1a/1b(/)/Bcrp(/) mice. In contrast, brain concentrations of aripiprazole in Mdr1a/1b(/)/Bcrp(/) mice were approximately 3- to 5-fold higher than those in normal mice, but concentrations in Bcrp(/) mice were comparable to values in normal mice (Figure 3, Table 2). As with aripiprazole, plasma dehydroaripiprazole concentrations in both Bcrp(/) and Mdr1a/1b(/)/Bcrp(/) mice were not drastically different from those in normal mice (the ratios of Cmax and AUCinf in Bcrp(/) to those in normal
Plasma or brain conc. (ng/mL or ng/g)
Figure 2. Plasma and brain concentration– time profiles of aripiprazole and dehydroaripiprazole after a single intravenous administration of aripiprazole to normal FVB mice at a dose of 2 mg/kg. Each point represents the mean ± SD of data from three mice.
10000
Plasma or brain conc. (ng/mL or ng/g)
P-gp/BCRP dysfunction and aripiprazole pharmacokinetics
DOI: 10.3109/00498254.2014.901585
Aripiprazole
1000 Plasma Brain
100 10 1 0.1 0.01 0
6 12 18 24 30 36 42 48 54 Time (h)
929
Dehydroaripiprazole
10000 1000
Plasma Brain
100 10 1 0.1 0.01
6 12 18 24 30 36 42 48 54 Time (h)
0
Table 1. Pharmacokinetic parameters of aripiprazole after a single intravenous administration of aripiprazole to normal FVB mice (2 mg/kg).
Compound Aripiprazole Dehydroaripiprazole
Specimen
CLtot (mL/h/kg)
Vdss (mL/kg)
Cmax (ng/mL or ng/g)
Tmax (h)
t1/2 (h)
AUCinf (ngh/mL or ngh/g)
Plasma Brain Plasma Brain
703 – – –
3770 – – –
– – 58.3 45.9
– – 8.0 4.0
4.4 4.1 4.9 3.8
2850 6550 987 680
Each parameter was calculated from the mean concentration–time profiles in plasma and brain. –, Not calculated.
10000
10000
Plasma
1000 100 10 1
Normal Bcrp (-/-) Mdr1a/1b/Bcrp (-/-)
0.1
Brain
1000
Concentration (ng/g)
Concentration (ng/mL)
Figure 3. Aripiprazole concentration–time profiles in plasma and brain after a single oral administration of aripiprazole (2 mg/kg) to normal, Bcrp knockout and Mdr1a/1b/ Bcrp knockout mice. Each point represents the mean ± SD of data from three mice.
100 10 1
Normal Bcrp (-/-) Mdr1a/1b/Bcrp (-/-)
0.1
0.01
0.01 0
6 12 18 24 30 36 42 48 54
0
Time (h)
6 12 18 24 30 36 42 48 54 Time (h)
Table 2. Pharmacokinetic parameters of aripiprazole and dehydroaripiprazole after a single oral administration of aripiprazole (2 mg/kg) to normal, Bcrp knockout and Mdr1a/1b/Bcrp knockout mice. Normal Compound Aripiprazole
Dehydroaripiprazole
Bcrp(/)
Mdr1a/1b(/)/Bcrp(/)
PK parameters
Plasma
Brain
Plasma
Brain
Plasma
Brain
Cmax (ng/mL or ng/g) Tmax (h) t1/2 (h) AUCinf (ng h/mL or ng h/g) F (%) Cmax (ng/mL or ng/g) Tmax (h) t1/2 (h) AUCinf (ng h/mL or ng h/g)
272 0.50 4.1 1810 64 60.1 8.0 4.4 950
751 0.50 4.5 3810 – 51.0 8.0 4.3 675
243 0.25 4.5 2400 84 84.0 8.0 4.5 1250
573 1.0 5.3 5400 – 55.7 8.0 4.2 821
304 0.50 4.6 2400 84 74.4 1.0 4.7 1310
2190 0.50 5.1 19 500 – 369 8.0 4.8 6220
Each parameter was calculated from the mean concentration–time profile in plasma and brain.
Y. Nagasaka et al.
Xenobiotica, 2014; 44(10): 926–932
mice: 1.4 and 1.3; corresponding ratios for Mdr1a/1b(/)/ Bcrp(/) mice: 1.2 and 1.4), whereas the brain concentrations in Mdr1a/1b(/)/Bcrp(/) mice were clearly higher than in normal mice (approximately 10-fold higher in the knockout mice on the AUCinf basis; Figure 4, Table 2). Brain to plasma concentration ratios (Kp, brain) in normal, Bcrp(/) and Mdr1a/1b(/)/ Bcrp(/) mice Based on the plasma and brain concentrations after oral administration, Kp,brain values of aripiprazole and dehydroaripiprazole were calculated and compared among normal, Bcrp(/) and Mdr1a/1b(/)/Bcrp(/) mice. The Kp,brain of aripiprazole in Mdr1a/1b(/)/Bcrp(/) mice was approximately 3.6-fold higher than in normal mice on average, while that in Bcrp(/) was comparable to values in normal mice (Table 3). The same was true for Kp,brain of dehydroaripiprazole, but the ratio of Kp,brain in Mdr1a/1b(/ )/Bcrp(/) mice to that in normal mice was higher for the metabolite, than the unchanged aripiprazole (ratio of Kp,brain in the knockout mice to that in normal mice was approximately 6.2; Table 3).
10000 Concentration (ng/mL)
Figure 4. Dehydroaripiprazole concentration– time profiles in plasma and brain after a single oral administration of aripiprazole (2 mg/kg) to normal, Bcrp knockout and Mdr1a/1b/Bcrp knockout mice. Each point represents the mean ± SD of data from three mice.
Discussion In the present study, we determine the plasma and brain concentrations of aripiprazole and dehydroaripiprazole after a single intravenous administration of aripiprazole in normal FVB mice, and compared values with those after a single oral administration were compared among normal, Bcrp(/) and Mdr1a/1b(/)/Bcrp(/) mice. As calculated from plasma concentrations after intravenous administration, the CLtot for aripiprazole in mice was 703 mL/h/kg and Vdss was 3770 mL/kg (Table 1), suggesting that aripiprazole has low clearance and a high volume of distribution in mice, considering reported values of hepatic blood flow and plasma volume (Davies & Morris, 1993). The pharmacokinetic characteristics of aripiprazole are also considered as possibly being similar between mice and humans, as various studies demonstrated that the compound showed low clearance (CLtot: 58.7 mL/ min) and relatively high volume of distribution (Vdss: 4.94 L/kg) in healthy male volunteers (Boulton et al., 2008; Mallikaarjun et al., 2004). In addition, time courses of aripiprazole and dehydroaripiprazole concentrations in the brain after a intravenous administration to normal mice were almost in parallel with those in plasma (Figure 2), suggesting 10000
Plasma
1000 100 10 1
Normal Bcrp (-/-) Mdr1a/1b/Bcrp (-/-)
0.1 0.01
Concentration (ng/g)
930
Brain
1000 100 10 1
Normal Bcrp (-/-) Mdr1a/1b/Bcrp (-/-)
0.1 0.01
0
6 12 18 24 30 36 42 48 54
0
6 12 18 24 30 36 42 48 54
Time (h)
Time (h)
Table 3. Brain to plasma concentration ratios (Kp, brain) of aripiprazole and dehydroaripiprazole after a single oral administration of aripiprazole (2 mg/kg) to normal, Bcrp knockout and Mdr1a/1b/Bcrp knockout mice. Aripiprazole Time (h) 0.25 0.5 1 2 4 8 12 24 48 Mean
Dehydroaripiprazole
Normal
Bcrp(/)
Mdr1a/1b(/)/Bcrp(/)
Normal
Bcrp(/)
Mdr1a/1b(/)/Bcrp(/)
1.33 ± 0.13 2.80 ± 0.44 2.15 ± 0.35 1.41 ± 0.56 2.06 ± 0.13 2.23 ± 0.04 2.19 ± 0.38 3.23 ± 0.22 3.90 ± 0.47 2.37
1.77 ± 0.46 (1.3) 2.03 ± 0.50 (0.7) 2.56 ± 0.48 (1.2) 2.71 ± 1.11 (1.9) 2.40 ± 0.37 (1.2) 1.97 ± 0.98 (0.9) 2.12 ± 0.35 (1.0) 2.75 ± 0.26 (0.9) 5.10 ± 0.65 (1.3) 2.60 (1.2)
3.87 ± 0.98* (2.9) 7.20 ± 0.99** (2.6) 7.41 ± 0.90*** (3.4) 8.17 ± 0.17*** (5.8) 8.08 ± 0.77*** (3.9) 9.18 ± 0.06*** (4.1) 8.46 ± 0.94*** (3.9) 6.60 ± 0.93** (2.0) 14.9 ± 3.65** (3.8) 8.21 (3.6)
0.31 ± 0.02 0.44 ± 0.05 0.49 ± 0.03 0.34 ± 0.16 0.63 ± 0.07 0.85 ± 0.04 0.77 ± 0.12 0.74 ± 0.02 0.91a 0.61
0.35 ± 0.01* (1.1) 0.42 ± 0.03 (1.0) 0.55 ± 0.03 (1.1) 0.58 ± 0.20 (1.7) 0.56 ± 0.11 (0.9) 0.68 ± 0.17 (0.8) 0.75 ± 0.14 (1.0) 0.73 ± 0.04 (1.0) 0.70 ± 0.08b (0.8) 0.59 (1.0)
1.24 ± 0.39* (4.0) 1.70 ± 0.36** (3.9) 2.56 ± 0.65** (5.2) 3.33 ± 0.68** (9.8) 4.56 ± 0.13*** (7.3) 5.31 ± 0.22*** (6.2) 5.69 ± 0.15*** (7.4) 3.83 ± 0.57*** (5.2) 6.38 ± 1.91b (7.0) 3.84 (6.2)
Data are presented as mean ± SD from three mice at each time point. Values in parentheses represent the ratios of Kp,brain (mean) in respective knockout mice to that in normal FVB mice. a Mean of two mice. b Statistical analysis was not performed for the Kp,values at 48 h because only two mice data were available for normal mice. *Versus normal, p50.05. **Versus normal, p50.01. ***Versus normal, p50.001.
DOI: 10.3109/00498254.2014.901585
that both compounds rapidly reached equilibrium between the plasma and brain. In the three types of mice examined here, plasma concentrations of aripiprazole after oral administration decreased with similar t1/2 values (approximately 4–5 h), which were also comparable to values after intravenous administration to normal mice (4.4 h) (Figure 3, Table 2). In general, the t1/2 of a drug can be expressed as 0.693 Vd/ CLtot. Accordingly, possible reasons that t1/2 values were similar among normal, Bcrp(/), and Mdr1a/1b(/)/ Bcrp(/) mice are (1) both Vd and CLtot were comparable among the three types of mice, (2) both Vd and CLtot increased or decreased in parallel and to a similar extent in Bcrp(/), and/or Mdr1a/1b(/)/Bcrp(/) mice. Meanwhile, P-gp and BCRP not only pump out drugs from the tissues such as brain or testes, but are also involved in the excretion of drugs from the liver or kidney. Thus, the dysfunction of these transporters may increase Vd for substrate drugs by enhancing distribution into tissues and/or decrease CLtot by reducing excretion, while CLtot and Vd are unlikely to change in the same direction. We therefore consider genetic deficiencies in both P-gp and BCRP to have almost no effect on either Vd or CLtot of aripiprazole in mice. In contrast, AUCinf for plasma and the resulting F values in Bcrp(/) and Mdr1a/1b(/)/Bcrp(/) mice were slightly higher than in normal mice, but the difference was not marked (approximately 1.3-fold higher in the knockout mice than in normal mice; Table 2). F can be expressed as Fa Fg Fh, where Fa denotes fraction absorbed, Fg intestinal availability and Fh hepatic availability. Fh can be described as 1 CLh/Qh, where CLh denotes hepatic clearance and Qh hepatic blood flow. Given that the CLtot for aripiprazole in mice was low as previously suggested, Fh is unlikely to increase even if biliary excretion of the unchanged drug is involved in the elimination of the compound in mice to some extent. In addition, there is generally little likelihood that the defect in P-gp and/or BCRP would lead to any decrease in the activities of intestinal and/or hepatic metabolism (increase in Fg and Fh) of a compound. Taken together, these present findings suggest that any slight increase in the absolute bioavailability (F) of this compound in Bcrp(/) and Mdr1a/1b(/)/Bcrp(/) mice is mainly due to the increase in Fa. Further, the extent of the bioavailability increase was comparable between the two knockout mouse strains, suggesting that BCRP rather than P-gp may make some minimal contribution, to the intestinal absorption of aripiprazole in mice. In humans, the involvement of BCRP in intestinal absorption is of little concern, as the absolute bioavailability in humans is reported to be 87% (AbilifyTM tablets prescribing information), which is even higher than that in mice in the present study (64%). As with aripiprazole, plasma concentrations of dehydroaripiprazole in Bcrp(/) and Mdr1a/1b(/)/Bcrp(/) mice were not markedly higher than those in normal mice. The ratio of AUCinf in these knockout mice to that in normal mice ranged from approximately 1.3 to 1.4, which is comparable to the corresponding ratio for aripiprazole. Further, the t1/2 values for dehydroaripiprazole were similar among normal, Bcrp(/) and Mdr1a/1b(/)/Bcrp(/) mice (Figure 4, Table 2). These results suggest that
P-gp/BCRP dysfunction and aripiprazole pharmacokinetics
931
deficiencies in these drug transporters also had little or almost no effect on the elimination (e.g. hepatic metabolism and/or biliary excretion, if any) of the metabolite, and that the slight increase in plasma concentrations in Bcrp(/) and Mdr1a/1b(/)/Bcrp(/) mice was largely due to the increase in unchanged aripiprazole concentrations. Brain concentrations of aripiprazole in Bcrp(/) mice were not significantly higher than in normal mice, with levels expected from the increase of plasma concentrations in the knockout mice. In contrast, Mdr1a/1b(/)/Bcrp(/) mice showed distinctly higher concentrations in the brain (knockout/normal AUCinf ratio: approximately 5; Table 2). The same was true for brain concentrations of dehydroaripiprazole, but this increasing tendency was more marked for this metabolite (knockout/normal AUCinf ratio: approximately 10; Table 2). The resulting Kp,brain values for aripiprazole and dehydroaripiprazole were comparable between normal and Bcrp(/) mice, while those in Mdr1a/1b(/)/Bcrp(/) mice were approximately 3.6- and 6.2-fold higher than in normal mice on average, respectively (Table 3). In several studies on the comparison of CNS penetration of various drugs among Mdr1a/1b(/)/Bcrp(/), and Mdr1a/1b(/)/Bcrp(/) mice, a number of drugs – such as erlotinib, lapatinib and GDC-0941 – showed a more than 10-fold increase in Kp,brain in Mdr1a/1b(/)/Bcrp(/) mice, compared with the normal (wild-type) mice, in the absence of a marked change in the defect of each transporter (Kodaira et al., 2010; Polli et al., 2009; Salphati et al., 2010). This cooperative role of P-gp and BCRP on the restriction of CNS penetration of dual substrates can be explained by their contribution to the net efflux at the BBB, as Kodaira et al. (2010) demonstrated using the following equations to describe the ratio of Kp (R) in Mdr1a/ 1b(/)/Bcrp(/), and Mdr1a/1b(/)/Bcrp(/) mice to that in normal FVB mice, respectively: RMdr1a=1bð=Þ ¼ 1 þ
RBcrpð=Þ ¼ 1 þ
PSPgp ; PSeff þ PSBcrp
PSBcrp ; PSeff þ PSPgp
RMdr1a=1bð=ÞBcrpð=Þ ¼ 1 þ
PSPgp þ PSBcrp ; PSeff
ð1Þ
ð2Þ
ð3Þ
where PSeff denotes the permeability surface area (PS) products for the passive diffusion, PSP-gp the active efflux mediated by P-gp on the blood-side membrane of endothelial cells in the brain and PSBcrp the active efflux mediated by Bcrp on the blood-side membrane of endothelial cells in the brain. For drugs with similar affinity for both P-gp and BCRP, P-gp plays a dominant role in the drug efflux from the brain, as P-gp protein levels are higher than those of BCRP at the mouse BBB. Consequently, RMdr1a/1b(/) is slightly larger than 1 and RBcrp(/) is less than RMdr1a/1b(/) or almost equal to 1, whereas RMdr1a/1b(/)/Bcrp(/) is markedly higher than 1 and even more than the combined levels from knockout mice for each transporter, as explained by the equations shown above and summarized by Agarwal et al. (2011).
932
Y. Nagasaka et al.
In contrast, the RMdr1a/1b(/)/Bcrp(/) values for aripiprazole and dehydroaripiprazole estimated in the present study were slightly higher than but not drastically different from the RMdr1a/1b(/) previously indicated (approximately 2–3 for aripiprazole and approximately 4 for dehydroaripiprazole) (Kirschbaum et al., 2010; Wang et al., 2009) and the RBcrp(/ ) was almost close to unity, implying that these two compounds have higher affinity for P-gp than BCRP, resulting in substantial contribution of P-gp on their CNS penetration with little impact of BCRP, in contrast to the intestinal absorption. Given that the intestinal concentrations of drugs are generally considered to be much higher than systemic concentrations, the efflux of aripiprazole mediated by P-gp might be saturated in intestinal absorption, whereas efflux mediated by BCRP might still affect the absorption of aripiprazole to some extent due to its lower affinity. At present, however, we have no information on the Km values of aripiprzole for these transporters, and further investigation is required to clarify the reason for the contrasting observations on the contribution of BCRP between intestinal absorption and CNS penetration. Of additional note, the brain disposition of aripiprazole and dehydroaripiprazole in schizophrenia patients with P-gp genetic polymorphisms may differ markedly from disposition in P-gp normal patients, as several single nucleotide polymorphisms (SNPs) in the MDR1 gene – especially 3435C>T (rs1045642, exon 26) and 2677G>T/A (rs2032582, exon 21) – may alter P-gp expression levels in human tissues (Hemauer et al., 2010; Hoffmeyer et al., 2000). In conclusion, plasma concentrations of aripiprazole and dehydroaripiprazole after oral administration of aripiprazole to mice were not greatly affected by the dysfunction of both Pgp and BCRP. In addition, brain penetration of aripiprazole and dehydroaripiprazole might be affected by P-gp function, but with little synergistic influence from BCRP.
Acknowledgements The authors thank Masafumi Furukawa, Hisako Naito, Hiroyuki Chijiwa, Mitsunari Suzuki, Tomoko Numata, Kazumi Ichige, Kumiko Takei and Takayuki Miyake (ADME & Tox. Research Institute, Sekisui Medical Co., Ltd.) for their contribution to the animal experiments.
Declaration of interest The authors report no conflicts of interest.
References Agarwal S, Hartz AM, Elmquist WF, Bauer B. (2011). Breast cancer resistance protein and P-glycoprotein in brain cancer: two gatekeepers team up. Curr Pharm Des 17:2793–802. Agarwal S, Sane R, Gallardo JL, et al. (2010). Distribution of gefitinib to the brain is limited by P-glycoprotein (ABCB1) and breast cancer resistance protein (ABCG2)-mediated active efflux. J Pharmacol Exp Ther 334:147–55. Bleakley S. (2012). Identifying and reducing the risk of antipsychotic drug interactions. Progr Neurol Psychiatry 16:20–4. Boulton DW, Kollia G, Mallikaarjun S, et al. (2008). Pharmacokinetics and tolerability of intramuscular, oral and intravenous aripiprazole in healthy subjects and in patients with schizophrenia. Clin Pharmacokinet 47:475–85. Bristol-Myers Squibb Company and Otsuka America Pharmaceutical Inc. AbilifyTM (aripiprazole) tablets prescribing information. Available at: http://www.abilify.com
Xenobiotica, 2014; 44(10): 926–932
Broekema WJ, De Groot IW, Van Harten PN. (2007). Simultaneous prescribing of atypical antipsychotics, conventional antipsychotics and anticholinergics—a European study. Pharm World Sci 29:126–30. Burris KD, Molski TF, Xu C, et al. (2002). Aripiprazole, a novel antipsychotic, is a high-affinity partial agonist at human dopamine D2 receptors. J Pharmacol Exp Ther 302:381–9. Davies B, Morris T. (1993). Physiological parameters in laboratory animals and humans. Pharm Res 10:1093–5. De Vries NA, Zhao J, Kroon E, et al. (2007). P-glycoprotein and breast cancer resistance protein: two dominant transporters working together in limiting the brain penetration of topotecan. Clin Cancer Res 13: 6440–9. Doran A, Obach RS, Smith BJ, et al. (2005). The impact of P-glycoprotein on the disposition of drugs targeted for indications of the central nervous system: evaluation using the MDR1A/1B knockout mouse model. Drug Metab Dispos 33:165–74. Giacomini KM, Huang SM, Tweedie DJ, et al. (2010). Membrane transporters in drug development. Nat Rev Drug Discov 9:215–36. Hemauer SJ, Nanovskaya TN, Abdel-Rahman SZ, et al. (2010). Modulation of human placental P-glycoprotein expression and activity by MDR1 gene polymorphisms. Biochem Pharmacol 79:921–5. Hoffmeyer S, Burk O, Von Richter O, et al. (2000). Functional polymorphisms of the human multidrug-resistance gene: multiple sequence variations and correlation of one allele with P-glycoprotein expression and activity in vivo. Proc Natl Acad Sci USA 97:3473–8. Ieiri I. (2012). Functional significance of genetic polymorphisms in P-glycoprotein (MDR1, ABCB1) and breast cancer resistance protein (BCRP, ABCG2). Drug Metab Pharmacokinet 27:85–105. Kirschbaum KM, Uhr M, Holthoewer D, et al. (2010). Pharmacokinetics of acute and sub-chronic aripiprazole in P-glycoprotein deficient mice. Neuropharmacology 59:474–9. Kodaira H, Kusuhara H, Ushiki J, et al. (2010). Kinetic analysis of the cooperation of P-glycoprotein (P-gp/Abcb1) and breast cancer resistance protein (Bcrp/Abcg2) in limiting the brain and testis penetration of erlotinib, flavopiridol, and mitoxantrone. J Pharmacol Exp Ther 333:788–96. Langan J, Shajahan P. (2010). Antipsychotic polypharmacy: review of mechanisms, mortality and management. The Psychiatrist 34: 58–62. Mallikaarjun S, Salazar DE, Bramer SL. (2004). Pharmacokinetics, tolerability, and safety of aripiprazole following multiple oral dosing in normal healthy volunteers. J Clin Pharmacol 44:179–87. Mitchell P. (2000). Therapeutic drug monitoring of psychotropic medications. Br J Clin Pharmacol 49:303–12. Nagasaka Y, Oda K, Iwatsubo T, et al. (2012). Effects of aripiprazole and its active metabolite dehydroaripiprazole on the activities of drug efflux transporters expressed both in the intestine and at the blood– brain barrier. Biopharm Drug Dispos 33:304–15. Nakagami T, Yasui-Furukori N, Saito M, et al. (2005). Effect of verapamil on pharmacokinetics and pharmacodynamics of risperidone: in vivo evidence of involvement of P-glycoprotein in risperidone disposition. Clin Pharmacol Ther 78:43–51. Polli JW, Olson KL, Chism JP, et al. (2009). An unexpected synergist role of P-glycoprotein and breast cancer resistance protein on the central nervous system penetration of the tyrosine kinase inhibitor lapatinib (N-{3-chloro-4-[(3-fluorobenzyl)oxy]phenyl}-6-[5-({[2(methylsulfonyl)ethyl]amino}methyl)-2-furyl]-4-quinazolinamine; GW572016). Drug Metab Dispos 37:439–42. Salphati L, Lee LB, Pang J, et al. (2010). Role of P-glycoprotein and breast cancer resistance protein-1 in the brain penetration and brain pharmacodynamic activity of the novel phosphatidylinositol 3-kinase inhibitor GDC-0941. Drug Metab Dispos 38:1422–6. Schmitt U, Abou El-Ela A, Guo LJ, et al. (2006). Cyclosporine A (CsA) affects the pharmacodynamics and pharmacokinetics of the atypical antipsychotic amisulpride probably via inhibition of P-glycoprotein (P-gp). J Neural Transm 113:787–801. Wang J, Zhu H, Markowitz J, et al. (2008). Antipsychotic drugs inhibit the function of breast cancer resistance protein. Basic Clin Pharmacol Toxicol 103:336–41. Wang JS, Zhu HJ, Donovan JL, et al. (2009). Aripiprazole brain concentration is altered in P-glycoprotein deficient mice. Schizophr Res 110:90–4. Wang JS, Zhu HJ, Markowitz JS, et al. (2006). Evaluation of antipsychotic drugs as inhibitors of multidrug resistance transporter P-glycoprotein. Psychopharmacology (Berl) 187:415–23.
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