311
Australian Dental Journal, August, 1978
Vo:unie 23, No. 4
The effect of irradiation and heat on the content of adrenaline in commercially manufactured local anaesthetic solutions a pilot study
-
D. C. Gerke, B.D.S., B.Sc.Dent.(Hons.)
G. A. Crabb, M.A.I.S.T., AND
D. B. Frewin, M.D., F.R.A.C.P.
L)t,pwfttietii of
Hiitticin
Pliy\iology
[itid
Pliurmucology, The Uiiiiter.\ity of Atlelaidc
AeslRAcl-carpules of commercially available local anaesthetic solutions containing adrenaline have been exposed to varying conditions of heat, ultra-violet and infra-red light over a period of two months. The adrenaline content in the solutions was assessed by fluorometric assay both at the commencement of study and at regular intervals over the period of exposure. Infra-red light appeared to have little or no effect on the concentration of adrenaline, while ultra-violet light, either alone or in combination with infra-red light, caused the adrenaline levels to diminish rapidly. The results suggest that the ultra-violet component of light is probably responsible for the breakdown of catecholamines in local anaesthetic solutions when these solution are stored in areas exposed to sunlight.
(Received f o r publication Novemher, 1 9 7 7 )
Introduction
The addition of adrenaline to local anaesthetic solutions has been shown to increase the efficacy, duration and extent of anaesthesia produced by these solutions. In addition, Huldtl showed that if adrenaline was incorporated into local anaesthetic solutions. a decreased onset time for anaesthesia occurred. Any reduction in the adrenaline content in local anaesthetic solutions below that level which was originally incorporated at the time of manufacture could therefore be expected to lead to a decrease in the efficacy of the anaesthesia that the particular solution should produce. It has been reported that commercial local anaesthetic solutions seem to display a decline in their incorporated adrenaline content with increasing age of the solutionz. In addition, it was shown
' Huldt,
S.-Factors influencing the efficiency of dental local anaesthetics in man. Acta Odont. Scand., 11, Suppl. 13, 1-79, 1953.
previously3 that exposure of lignocaine 2 per cent adrenaline 1:80,000*, or prilocaine 3 per cent adrenaline 1 :300,00OP,to sunlight markedly decreased the adrenaline content of these solutions over a six month period. The present study has been carried out in an attempt to determine the components in sunlight that may have contributed to the decline in the adrenaline content which was observed in the previous studies. Method
The semi-automated Technicon fluorometric catecholamine assay described previously by Head
* Xyloeaine.
(Astra).
f Citanest 30. (Astra).
D. C., Frewin, D. B., and Waterson, J . G."erke, The effects of commercial local anaesthetic solutions on the isolated rabbit ear artery. Austral. D. J., 22:4, 289-294 (Aug 1977. SGerke, D. C., drabb, G . A,, Frewin, D. B.,, and Frost, B. R.-The effect of storage on the activity of adrenaline in local anaesthetic solutions: an evaluation using bioassay and fluorometric techniques. Austral. D. J., 22:6, 423-427 (Dec.) 1977.
312
Australian Dental Journal, August. 1978
and his colleagues4 was used to analyse the adrenaline content in the commercial local anaesthetic solutions. The control solutions for the assay were made in the laboratory to the exact formula of the commercial solutions.
(2) Infra-red light irradiation (Philips 240V 150W E/470 IR lamp). Carpules of local anaesthetic solutions were set at a distance of 250 nim from the filament and the temperature maintained at 3 O O C .
-
0
+ 4
*
" Y
0
-
? .
rn
m 0 L L
0
2
p
M
0
60
0 D u r a t l o n (days)
30
60
D u r a t i o n (days) Dry h e a t
Of
45'C
Ultra-violet irradiation Yhite l i g h t Irradiation
Fig. 2.-The results of the Technicon fluorometric assay OF lignocaine solutions kept for t w o months under the same conditions as those listed in Fig. 1 . (Ad = adrenaline.)
Infra-red l i g h t i m d i a t i o n Infra-red l i g h t and u l t r a - v i o l e t
light cohined irradiation
FiE. 1 .-The results of the Technicon fluorometric assay of carpules of prilocaine solution kept for two months under the conditions listed in the key. (Ad = adrenaline.)
The lignocaine and prilocaine solutions were obtained from the manufacturer and a representative sample from each group analysed for their adrenaline content. The content of adrenaline that was originally measured in the two solutions was nominated as 100 per cent and all subsequent measurements that were made were compared with these figures. Following the initial measurements, batches of the two solutions were continuously exposed to various conditions over a period of two months. At regular intervals during this period an average of four carpules of anaesthetic were removed and nnalysed for their adrenaline content. The conditions to which the solutions were exposed were as follows:( 1 ) Dry heat of 45OC by placement in a hot oven.
4
Head. R . J.. Crabb. G . A.. de la Lande. I . S.. and Fikw-in ~ D .B.-Semi-automated catecholamine assay. Aust. >. Exp. Biol. Med. Sci.. 55:Part 2, 213-223 (Apr.) 1977.
(3) White light irradiation (Philips T L 20W/47 fluorescent tube). Carpules were placed at a distance of 250 mm from the tube and the temperature maintained at 25OC. (4) Ultra-violet light irradiation (Philips TL 40W/08RSF fluorescent tube). Carpule5 were set at a distance of 250 mm from the tube and the temperature maintained at 25OC. ( 5 ) A combination of (2) and (4) with carpules placed at 250 mm from the filament and tube and the temperature maintained at 30'C. ResuIts
Over the sixty-day treatment period, infra-red irradiation did not appear to markedly affect the adrenaline content in the two different local anaesthetic solutions (Fig. I , 2). The adrenaline content in the prilocaine solution appeared to fall off between the thirty to sixty day period after constant exposure to white light. Although there appeared to be some similarity in the decline of the adrenaline content in the lignocaine solution after sixty days of white light irradiation, the fall was not as great as that seen with the prilocaine solution. When either of the local anaesthetic solutions was irradiated with ultra-violet light or ultra-violet light combined with infra-red light, the adrenaline content of the solutions approached one-tenth of
Australian Dental Journal, Augubt. 1978 the original content within forty to fifty days from the commencement of the experiment (Fig. I , 2). Dry heat (45OC) appeared to cause some decline in adrenaline content in both the local anaesthetic solutions, but the breakdown of adrenaline was not as great as when ultra-violet irradiation was involved. Discussion
Huldtl has shown that when constant volumes of solutions of lignocaine (2 per cent) mixed with varying concentrations of adrenaline were injected into the oral cavity, the percentage of effective anaesthesia decreased as the concentration of adrenaline fell. For this reason, the reports by Gerke and colleagues2J. which showed a decline in the adrenaline levels in commercially produced local anaesthetic solutions stored under different conditions, needed further investigation. The present study has thus been directed at determining the component(s) in sunlight which may have been responsible for the decline in adrenaline concentration which Gerke and his associates3 recorded. Although the number of carpules analysed at each phase in this study was relatively small and the quantity of light striking each carpule was not precisely quantitated, an interesting trend was noticed over the two-month period. Infra-red light appeared to have little or no effect on the adrenaline concentration in the prilocaine or lignocaine solutions. White light had an effect on
313 the adrenaline concentration but not until at least thirty days had elapsed. Dry heat also appeared to have some effect but this was certainly not as great as the effect of ultra-violet light. Ultraviolet light, either alone or in combination with infra-red light, caused the adrenaline concentration in both anaesthetic solutions to rapidly diminish. So great was the effect that, after forty to fifty days, the residual adrenaline in the local anaesthetic solutions was less than one-tenth of its original concentration. These latter results would indicate that it was the ultra-violet component of sunlight that contributed to the breakdown of adrenaline in the local anaesthetic solutions that were stored on the window-sill and subsequently evaluated by bioassay and fluorometric analysis3. The findings of the present study again raise the question of storage of local anaesthetic solutions and would imply that this is best achieved in a cool and dark environment. Acknowledgements
We wish to thank Astra Chemicals for providing us with the commercial local anaesthetic solutions which were examined in this study and for financial support. Department of Human Physiology and Pharmacology, The University of Adelaide, Frome Road, Adelaide, S.A., 5000.
Australian Dental Journal, August, 1978
Vo:unie 23, No. 4
The effect of irradiation and heat on the content of adrenaline in commercially manufactured local anaesthetic solutions a pilot study
-
D. C. Gerke, B.D.S., B.Sc.Dent.(Hons.)
G. A. Crabb, M.A.I.S.T., AND
D. B. Frewin, M.D., F.R.A.C.P.
L)t,pwfttietii of
Hiitticin
Pliy\iology
[itid
Pliurmucology, The Uiiiiter.\ity of Atlelaidc
AeslRAcl-carpules of commercially available local anaesthetic solutions containing adrenaline have been exposed to varying conditions of heat, ultra-violet and infra-red light over a period of two months. The adrenaline content in the solutions was assessed by fluorometric assay both at the commencement of study and at regular intervals over the period of exposure. Infra-red light appeared to have little or no effect on the concentration of adrenaline, while ultra-violet light, either alone or in combination with infra-red light, caused the adrenaline levels to diminish rapidly. The results suggest that the ultra-violet component of light is probably responsible for the breakdown of catecholamines in local anaesthetic solutions when these solution are stored in areas exposed to sunlight.
(Received f o r publication Novemher, 1 9 7 7 )
Introduction
The addition of adrenaline to local anaesthetic solutions has been shown to increase the efficacy, duration and extent of anaesthesia produced by these solutions. In addition, Huldtl showed that if adrenaline was incorporated into local anaesthetic solutions. a decreased onset time for anaesthesia occurred. Any reduction in the adrenaline content in local anaesthetic solutions below that level which was originally incorporated at the time of manufacture could therefore be expected to lead to a decrease in the efficacy of the anaesthesia that the particular solution should produce. It has been reported that commercial local anaesthetic solutions seem to display a decline in their incorporated adrenaline content with increasing age of the solutionz. In addition, it was shown
' Huldt,
S.-Factors influencing the efficiency of dental local anaesthetics in man. Acta Odont. Scand., 11, Suppl. 13, 1-79, 1953.
previously3 that exposure of lignocaine 2 per cent adrenaline 1:80,000*, or prilocaine 3 per cent adrenaline 1 :300,00OP,to sunlight markedly decreased the adrenaline content of these solutions over a six month period. The present study has been carried out in an attempt to determine the components in sunlight that may have contributed to the decline in the adrenaline content which was observed in the previous studies. Method
The semi-automated Technicon fluorometric catecholamine assay described previously by Head
* Xyloeaine.
(Astra).
f Citanest 30. (Astra).
D. C., Frewin, D. B., and Waterson, J . G."erke, The effects of commercial local anaesthetic solutions on the isolated rabbit ear artery. Austral. D. J., 22:4, 289-294 (Aug 1977. SGerke, D. C., drabb, G . A,, Frewin, D. B.,, and Frost, B. R.-The effect of storage on the activity of adrenaline in local anaesthetic solutions: an evaluation using bioassay and fluorometric techniques. Austral. D. J., 22:6, 423-427 (Dec.) 1977.
312
Australian Dental Journal, August. 1978
and his colleagues4 was used to analyse the adrenaline content in the commercial local anaesthetic solutions. The control solutions for the assay were made in the laboratory to the exact formula of the commercial solutions.
(2) Infra-red light irradiation (Philips 240V 150W E/470 IR lamp). Carpules of local anaesthetic solutions were set at a distance of 250 nim from the filament and the temperature maintained at 3 O O C .
-
0
+ 4
*
" Y
0
-
? .
rn
m 0 L L
0
2
p
M
0
60
0 D u r a t l o n (days)
30
60
D u r a t i o n (days) Dry h e a t
Of
45'C
Ultra-violet irradiation Yhite l i g h t Irradiation
Fig. 2.-The results of the Technicon fluorometric assay OF lignocaine solutions kept for t w o months under the same conditions as those listed in Fig. 1 . (Ad = adrenaline.)
Infra-red l i g h t i m d i a t i o n Infra-red l i g h t and u l t r a - v i o l e t
light cohined irradiation
FiE. 1 .-The results of the Technicon fluorometric assay of carpules of prilocaine solution kept for two months under the conditions listed in the key. (Ad = adrenaline.)
The lignocaine and prilocaine solutions were obtained from the manufacturer and a representative sample from each group analysed for their adrenaline content. The content of adrenaline that was originally measured in the two solutions was nominated as 100 per cent and all subsequent measurements that were made were compared with these figures. Following the initial measurements, batches of the two solutions were continuously exposed to various conditions over a period of two months. At regular intervals during this period an average of four carpules of anaesthetic were removed and nnalysed for their adrenaline content. The conditions to which the solutions were exposed were as follows:( 1 ) Dry heat of 45OC by placement in a hot oven.
4
Head. R . J.. Crabb. G . A.. de la Lande. I . S.. and Fikw-in ~ D .B.-Semi-automated catecholamine assay. Aust. >. Exp. Biol. Med. Sci.. 55:Part 2, 213-223 (Apr.) 1977.
(3) White light irradiation (Philips T L 20W/47 fluorescent tube). Carpules were placed at a distance of 250 mm from the tube and the temperature maintained at 25OC. (4) Ultra-violet light irradiation (Philips TL 40W/08RSF fluorescent tube). Carpule5 were set at a distance of 250 mm from the tube and the temperature maintained at 25OC. ( 5 ) A combination of (2) and (4) with carpules placed at 250 mm from the filament and tube and the temperature maintained at 30'C. ResuIts
Over the sixty-day treatment period, infra-red irradiation did not appear to markedly affect the adrenaline content in the two different local anaesthetic solutions (Fig. I , 2). The adrenaline content in the prilocaine solution appeared to fall off between the thirty to sixty day period after constant exposure to white light. Although there appeared to be some similarity in the decline of the adrenaline content in the lignocaine solution after sixty days of white light irradiation, the fall was not as great as that seen with the prilocaine solution. When either of the local anaesthetic solutions was irradiated with ultra-violet light or ultra-violet light combined with infra-red light, the adrenaline content of the solutions approached one-tenth of
Australian Dental Journal, Augubt. 1978 the original content within forty to fifty days from the commencement of the experiment (Fig. I , 2). Dry heat (45OC) appeared to cause some decline in adrenaline content in both the local anaesthetic solutions, but the breakdown of adrenaline was not as great as when ultra-violet irradiation was involved. Discussion
Huldtl has shown that when constant volumes of solutions of lignocaine (2 per cent) mixed with varying concentrations of adrenaline were injected into the oral cavity, the percentage of effective anaesthesia decreased as the concentration of adrenaline fell. For this reason, the reports by Gerke and colleagues2J. which showed a decline in the adrenaline levels in commercially produced local anaesthetic solutions stored under different conditions, needed further investigation. The present study has thus been directed at determining the component(s) in sunlight which may have been responsible for the decline in adrenaline concentration which Gerke and his associates3 recorded. Although the number of carpules analysed at each phase in this study was relatively small and the quantity of light striking each carpule was not precisely quantitated, an interesting trend was noticed over the two-month period. Infra-red light appeared to have little or no effect on the adrenaline concentration in the prilocaine or lignocaine solutions. White light had an effect on
313 the adrenaline concentration but not until at least thirty days had elapsed. Dry heat also appeared to have some effect but this was certainly not as great as the effect of ultra-violet light. Ultraviolet light, either alone or in combination with infra-red light, caused the adrenaline concentration in both anaesthetic solutions to rapidly diminish. So great was the effect that, after forty to fifty days, the residual adrenaline in the local anaesthetic solutions was less than one-tenth of its original concentration. These latter results would indicate that it was the ultra-violet component of sunlight that contributed to the breakdown of adrenaline in the local anaesthetic solutions that were stored on the window-sill and subsequently evaluated by bioassay and fluorometric analysis3. The findings of the present study again raise the question of storage of local anaesthetic solutions and would imply that this is best achieved in a cool and dark environment. Acknowledgements
We wish to thank Astra Chemicals for providing us with the commercial local anaesthetic solutions which were examined in this study and for financial support. Department of Human Physiology and Pharmacology, The University of Adelaide, Frome Road, Adelaide, S.A., 5000.
