CA1266002A - Acne treating composition containing l-cysteine - Google Patents
Acne treating composition containing l-cysteineInfo
- Publication number
- CA1266002A CA1266002A CA000492037A CA492037A CA1266002A CA 1266002 A CA1266002 A CA 1266002A CA 000492037 A CA000492037 A CA 000492037A CA 492037 A CA492037 A CA 492037A CA 1266002 A CA1266002 A CA 1266002A
- Authority
- CA
- Canada
- Prior art keywords
- composition
- cysteine
- propylene
- phenoxetol
- pharmaceutically acceptable
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
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- Cosmetics (AREA)
Abstract
ABSTRACT
Pharmaceutical compositions useful in the treatment of acne comprising L-cysteine or a pharmaceutically acceptable salt thereof and an antibacterial agent such as propylene phenoxetol together with a pharmaceutically acceptable carrier are described. A preferred composition is in the form of a self-supporting aqueous gel containing L-cysteine hydrochloride and propylene phenoxetol.
Pharmaceutical compositions useful in the treatment of acne comprising L-cysteine or a pharmaceutically acceptable salt thereof and an antibacterial agent such as propylene phenoxetol together with a pharmaceutically acceptable carrier are described. A preferred composition is in the form of a self-supporting aqueous gel containing L-cysteine hydrochloride and propylene phenoxetol.
Description
~L2~6~
The present invention relates to pharmaceutical compositions useful in the treatment of acne which compositions comprise L-cysteine or a pharmaceutically acceptable salt thereof and propylene phenoxetol.
Anti-acne treatments axe well known but none are sufficiently satisfactory as to obviat~ the need of a further method of treatment. Known methods of treatment by ultra-violet radiation, x-rays or surgery can cause tissue to be destroyed or the sebaceous glands to atrophy;
conventional oestrogen therapy similarly atrophies the sebaceous glands and may additionally be unacceptable to female patients and may require a consi~erable time to have an effect; and treatment with benzoyl peroxide can cause local irritation. Clearly it would be desirable lS to offer an alternative method of treating acneO
The present inven~ion is based upon the discovery that compositions containing L cysteine and propylene phenoxetol may be used to treat acne without an unacceptable level of undesirable side effects such as the destruction of tissue to an unacceptable degree.
Accordingly, the present invention provides a pharmaceutical composition useful in the treatment of acne which composition comprises L-cysteine or a pharmaceutically acceptable salt thereof and propylene phenoxetol.
One of the considerable advantages of using cysteine in the treatment of acne is that the medical prac$itioner will be aware that it is a natural a~ino aci*,~ so that confidence may be felt in that unconventional and possibly irritant materials such as thioglycolic acid can be avoided (U.S. Patent No.
4107330 discloses the topical applications of thioglycolic acid in the treatment of acne). Organic sulfhydryl and in particular N-acetyl cysteine have been applied to the skin in order to reduce sebum production (see U.X. Patent No. 1317773) but they were not shown to have any effect on acne. L-cysteine has been used in the treatment of ()02 eye diseases (see German Published Patent Application No. 2441621) but that use is unrelated to the treatment of acne.
Propylene phenoxetol, l-phenoxypropan-2-ol, has been used in topical compositions for ~he treatment of skin bacterial infections and skin fungal infections.
Its use, together with L-cysteine in the treatment of acne has not been disclosed or suggested.
The usefulness of L-cysteine and propylene phenoxetol in the treatment of acne is therefore particularly surprisiny.
The L~cysteine and propylene phenoxetol are normally applied in the form of a pharmaceutical composition which comprises L-cysteine or a pharmaceutically acceptable salt thereof and propylene phenoxetol and a pharmaceutically acceptable carrier therefor. The L-cysteine may have D-cysteine in association therewith if desired but normally and preferably L~cysteine is employed free of D-cysteine.
Any convenient composition may be employed as long as it is free of oxidising agents or other agents incompatible with L-cysteine opropylene phenoxetol.
Compositions analogous to those of the aforementioned patent documents may be employed if desired. However it is preferred to employ a self-supporting aqueous gel.
~ ccordingly this invention provides a pharmaceutical composition adapted for topical administration in the form of a self-supporting aqueous gel containing L-cysteine or a pharmaceutically acceptable salt thereof and propylene phenoxetol.
Acceptable salts of cysteine include those with topically acceptable metallic ions or nitrogenous bases or topically acceptable acids. A particularly apt salt is the hydrochloride. By a self-supporting gel is meant a gel which when applied to an area of skin remains in con~act with the area.
Most suitably the composition of this invention will contain from 0.1 to 15% o~ L-cysteine or a pharmaceutically acceptable salt thereof, more favourably
The present invention relates to pharmaceutical compositions useful in the treatment of acne which compositions comprise L-cysteine or a pharmaceutically acceptable salt thereof and propylene phenoxetol.
Anti-acne treatments axe well known but none are sufficiently satisfactory as to obviat~ the need of a further method of treatment. Known methods of treatment by ultra-violet radiation, x-rays or surgery can cause tissue to be destroyed or the sebaceous glands to atrophy;
conventional oestrogen therapy similarly atrophies the sebaceous glands and may additionally be unacceptable to female patients and may require a consi~erable time to have an effect; and treatment with benzoyl peroxide can cause local irritation. Clearly it would be desirable lS to offer an alternative method of treating acneO
The present inven~ion is based upon the discovery that compositions containing L cysteine and propylene phenoxetol may be used to treat acne without an unacceptable level of undesirable side effects such as the destruction of tissue to an unacceptable degree.
Accordingly, the present invention provides a pharmaceutical composition useful in the treatment of acne which composition comprises L-cysteine or a pharmaceutically acceptable salt thereof and propylene phenoxetol.
One of the considerable advantages of using cysteine in the treatment of acne is that the medical prac$itioner will be aware that it is a natural a~ino aci*,~ so that confidence may be felt in that unconventional and possibly irritant materials such as thioglycolic acid can be avoided (U.S. Patent No.
4107330 discloses the topical applications of thioglycolic acid in the treatment of acne). Organic sulfhydryl and in particular N-acetyl cysteine have been applied to the skin in order to reduce sebum production (see U.X. Patent No. 1317773) but they were not shown to have any effect on acne. L-cysteine has been used in the treatment of ()02 eye diseases (see German Published Patent Application No. 2441621) but that use is unrelated to the treatment of acne.
Propylene phenoxetol, l-phenoxypropan-2-ol, has been used in topical compositions for ~he treatment of skin bacterial infections and skin fungal infections.
Its use, together with L-cysteine in the treatment of acne has not been disclosed or suggested.
The usefulness of L-cysteine and propylene phenoxetol in the treatment of acne is therefore particularly surprisiny.
The L~cysteine and propylene phenoxetol are normally applied in the form of a pharmaceutical composition which comprises L-cysteine or a pharmaceutically acceptable salt thereof and propylene phenoxetol and a pharmaceutically acceptable carrier therefor. The L-cysteine may have D-cysteine in association therewith if desired but normally and preferably L~cysteine is employed free of D-cysteine.
Any convenient composition may be employed as long as it is free of oxidising agents or other agents incompatible with L-cysteine opropylene phenoxetol.
Compositions analogous to those of the aforementioned patent documents may be employed if desired. However it is preferred to employ a self-supporting aqueous gel.
~ ccordingly this invention provides a pharmaceutical composition adapted for topical administration in the form of a self-supporting aqueous gel containing L-cysteine or a pharmaceutically acceptable salt thereof and propylene phenoxetol.
Acceptable salts of cysteine include those with topically acceptable metallic ions or nitrogenous bases or topically acceptable acids. A particularly apt salt is the hydrochloride. By a self-supporting gel is meant a gel which when applied to an area of skin remains in con~act with the area.
Most suitably the composition of this invention will contain from 0.1 to 15% o~ L-cysteine or a pharmaceutically acceptable salt thereof, more favourably
2.0 to 12% and preferably from 4 to 8~ (% terms when used herein are expressed on a wt./wt. ~asis)~
1~60 Most suitably the composition of this invention will contain from 0.1 to 5% of propylene phenoxetol, 1-phenoxypropan-2-ol, more favourably 1 to 4%, and preferably from 1.5 to 3~, for example 2%.
Optionally, ~hough not preferred, the composition of this invention will contain preservative.
Preservatives which are most apt are those commonly used in pharmaceutical compositions. Preferably the preservative will he benzoic acid, in an amount of 10 0.01 to 0.5% preferably 0.05 to 0.2%.
Normally and preferably the composition will contain a pharmaceutically acceptable gelling agent such as cellulose derivatives or gums or starches or alginates and polymers such as polyvinyl pyrrolidone or polyvinyl alcohol or polyethoxy-polypropoxy glycol copolym~rs, but a preferred gelling agent is a polyacrylic acid lightly cross-linked with triallyl sucrose. Such polymers are known as carboxyvinyl polymers of which the Carbopols (Trade Mark) are one commercial embodiment. To form gels these polymers must be neutralised~ Suitable neutralising agents include solutions of alkali metal or ammonium hydroxides and nitrogenous bases.
preferred neutraliser is a solution of sodium hydroxide.
2 ~
Suitably the pharmaceutical compositions of the present invention in the form of a gel will contain from 0.1 to 5% of gelling agent depending on the efficacy of the agent, more suitably 0.5 to 4~ and preferably 5 l to 3%, for example 1.5%, 2% or 2.5~.
Normally and preferably the composition will contain a humectant to prevent the gel drying in use.
Such humectants include alkylene glycols. A particularly preferred humectant is propylene glycol~ This agent has the added advantage in easing the dispersion of the - gelling agent in the bulk of the water during preparation.
Suitably the composition may contain from 2 to lO~ of humectant and preferably 3 to 7%.
Most suitably the pH of the composition will be controlled to prevent oxidation of L-cysteine base to cystine which occurs readily in solutions having a pH
value of greater than 8. The suitable range of pH value is from ~ to 87 most suitably from 3 to 6 and preferably ~ to 6.
The pH value of a gel composition may also depend upon the choice of gelling agent and the vi~cosity o~
required for the final gel. Thus, if the pH value is at the higher end of the range a hydroxyethyl cellulose gelling agent may be used and for gels of lower pH
the preferred gelling agent is a polyacrylic acid ligh~ly cross-linked by triallyl sucrose, when for example pH
values of 4 . 5 to 5.5 are employed.
The viscosity of the final gel were measured using a Ferranti-Shirley cone and plate viscometer using the following parameters, 4 cm cone 120 second sweep time 600g cm 1 torque spring 10 rpm speed 25~C temperature , The apparent viscosity at maximum sheer (10 r.p.m.
= 113.7 sec ) is suitably between 30 and 80 poise and is preferably between 60 and 75 poise.
: ~ptionally the compositions of the present invention may also contain other ingredients including perfumes and inert fillers such as titanium dioxide to provide a white rather than colourless gel.
~L2 fi6~
- B -Normally and preferably the water used in ~he composition will be freshly distilled water which has been de-oxygenated by boiling and allowed to cool with filtered 'inert' gas bubbling thr~ugh lt. By 'inert' gas is meant a non-oxidising gas for cysteine, for example carbon dioxide, particularly preferred is nitrogen. It is also envisaged that any type of water for example deonized water, may be used provided it i5 degassed to remove oxygen and maintained thereafter under nitrogen.
L-cysteine and its salts are readily oxidised in aqueous solutions by oxygen dissolved in the water, hence removal of this oxygen and isolation of this solution from air, avoids oxidation of L-~ysteine and its salts.
The particularly favoured form of the composition of the present invention comprises from 2 to 12% of L-cysteine hydrochloride, 1 to 4~ of propylene phenoxetol, 2 to 10% propylene glycol, 0.1 to 5% polyacrylic acid cross-linked by triallyl sucrose, sodium hydroxide solution to give a pH of 5O4 and sufficient water to adjust the volume to lOQ~.
A preferred form of the composition of the present invention comprises from 4 to 8% of L-cysteine, 1.5 60~
to 3% propylene phenoxetol, 5% propylene glycol, 1.5 polyacrylic acid lightly cross-linked with triallyl sucrose, sodium hydroxide solution to adjust the pH of 5 4 and sufficient water to ad3ust the volume to 100%.
Typically the composition of the present ~ r~ e ~
invention will be packed into ~ ~ laquexed aluminium tubes~
In a second aspect ~herefore the invention provides a method of treating acne which comprises applying top.ically to the affected areas an effective amount of I,-cysteine or a, pharmaceutically acceptable salt thereof and propylene phenoxetol. The composition : will be applied topically to the affected area 2 times daily or more frequently if required.
In severe cases it may be desirable to apply the composition to the affected area up to 6 times a day for example 2, 3, 4, 5 or 6 times daily. Generally 2, 3 or 4 applications daily are most convenient and usually 2 or 3 applications will be made. In mild cases a single application per day may be envisaged.
Generally, treatment will last for at least 7 days and r~
1;;~Ç~6~
may proceed for up to 14 to 23 days or even longer if a physician considers it desirable.
In view of the susceptibility of cysteine to oxidation, the skilled ~uorker will be aware that the compositions employed will be free of agents that would oxidise the cysteine.
Although propylene phenoxetol is the preferred anti-bacterial agent in a less favoured aspect alternative anti-bacterial agents may be employed. Thus in a broader aspect the present invention provides a pharmaceutical composition useful in the treatment of acne which composition comprises L~cysteine or a pharmaceutically acceptable salt thereof and an anti-bacterial agent.
Aptly the composition will contain from 0.1 to 15% of I~cysteine or a pharmaceutically acceptable salt thereof.
Suitably the composition will contain from 0.2 -to 2.07o L,cysteine or a pharmaceutically acceptable salt thereof, more suitably will contain 0.25 to 1.5~o and preferably 0.3 to 0.5%, for exa~ple 0.35o, 0.4070 and 0.45/~ Of I,cysteine or a 20 pharmaceutically acceptable salt thereof. Preferably the hydrochloride of L-cys-teine is employed.
The effectiveness of compositions containing such low concentrations of L,cysteine with the antibacterial agent is particularly surprising. Such concen-trations have the added 25 advantage of being particularly friendly towards the skin.
Apt anti-bacterial agents are those which are compatible with L,cysteine. Suitable anti-bacterial agents include quaternary ammonium salts, for example ben~alkonium chloride and propylene phenoxetol. m e preferred anti-bacterial agent is propylene phenoxetol.
The following Examples are illustrative of the invention.
Example 1 An aqueous gel was made containing:
L-cysteine 7.~/~ w/w 210g Propylene phenoxetol 2.5% w/w 75g Propylene glycol 4.5% w/w 135g Carbopol 934P 2.0~o w/w 60g Sodium hydroxide solution to adjust the p~ to 5.4 Distilled water to adjust the volume to 1007o w/w 2520g.
me freshly distilled water was boiled to remove dissolved oxygen and allowed to cool with filtered nitrogen bubbling through. Nitrogen was bubbled through the buIk of the camposition for the entirety of the process including the filling. The Carbopol 934P was dissolved in the water by warming and stirring. Then the water was allowed to cool to ambient tenmperature. l`he propylene phenoxetol was dispersed in the propylene glycol and then added to the cool water with stirring. The L-cysteine was then dissolved in the solution and the p~I adjusted to pH 5.4 using sodium hydroxide solution. The weight of solution was adjusted to the weight re~uired by addition of dea~ygenated water. The resultant solution was mixed for a further 15 minutes under a nitrogen blanket. The resultant clear product was transferred to a tube filling apparatus under a blanket of nitrogen. The product was filled in a conventional manner into araldite lacquered aluminiun ~Ibes which have been flushed with nitrogen.
The tubes were sealed immediately.
The gel was dispensed from the tube as required.
Example 2 - An aqueous gel was made containing:
L,cysteine 8.070 Propylene phenoxetol 2. G7o Propylene glycol 7.0%
C~rbopol 934P 1.25%
Titanium dioxide 0.25,~
Perfume 0.05%
Sodium hydroxide solution to adjust ~I to 5.2 Distilled water to adjust the weight to lOOYo.
The gel was formed and packed using the methods described in Example 1. The titanium dioxide and perfume were added along with the propylene phenoxetol after first mixing with the propylene glycol.
,:
Example 3 An aqueous gel was made containing:
Lrcysteine hydrochloride lO~o Propylene phenoxetol 2 Propylene glycol 6~o Carbopol 934P 2qo Sodium hydroxide solution to adjust the pH to 4.5 Distilled water to adjust the weight to lOOg.
m e gel U~5 prepared and packaged in a si~ilar manner to that described in ~xa~ple 1.
Exa~ple 4 -An aqueous gel was prepared containing:
L,cysteine hydrochloride 0.45qO
Propylene pheno~etol 2.5~
Propylene glycol 6.0,~o Carbopol 934P 1.5~
litanium dioxide 0.25%
Perf~une 0.06,~o Sodium hydroxide solution to adjust the p~l to 5.6 Distilled water to adjust the weight to lOOg.
The gel was forned in a similar manner to that described in Example 2.
~6~
Example 5 An aqueous gel was prepared containing:
L,cysteine 0.35%
Propylene phenoxetol 2.0%
Propylene glycol 7.0%
Carbopol 93~P 1.25%
Perfume 0.0570 Sodium hydl-oxide solution to adjust the pH to 5.2 Distilled water to adjust the weight to lOOg.
m e gel was formed in a similar manner to that described in Example 1.
A clinical trial was carried out on 20 human volunteers suffering from acne. A gel having a formulation described in Example 1 was applied to the effec,ed areas twice a day for 10 weeks.
These areas were inspected after 2, 4, 6, 8 and 10 weeks of treatment. At the end bf 10 weeks the physician conducting the trial concluded that the L-cysteine/propylene phenoxetol gel was an efficacious treatment for acne.
1~60 Most suitably the composition of this invention will contain from 0.1 to 5% of propylene phenoxetol, 1-phenoxypropan-2-ol, more favourably 1 to 4%, and preferably from 1.5 to 3~, for example 2%.
Optionally, ~hough not preferred, the composition of this invention will contain preservative.
Preservatives which are most apt are those commonly used in pharmaceutical compositions. Preferably the preservative will he benzoic acid, in an amount of 10 0.01 to 0.5% preferably 0.05 to 0.2%.
Normally and preferably the composition will contain a pharmaceutically acceptable gelling agent such as cellulose derivatives or gums or starches or alginates and polymers such as polyvinyl pyrrolidone or polyvinyl alcohol or polyethoxy-polypropoxy glycol copolym~rs, but a preferred gelling agent is a polyacrylic acid lightly cross-linked with triallyl sucrose. Such polymers are known as carboxyvinyl polymers of which the Carbopols (Trade Mark) are one commercial embodiment. To form gels these polymers must be neutralised~ Suitable neutralising agents include solutions of alkali metal or ammonium hydroxides and nitrogenous bases.
preferred neutraliser is a solution of sodium hydroxide.
2 ~
Suitably the pharmaceutical compositions of the present invention in the form of a gel will contain from 0.1 to 5% of gelling agent depending on the efficacy of the agent, more suitably 0.5 to 4~ and preferably 5 l to 3%, for example 1.5%, 2% or 2.5~.
Normally and preferably the composition will contain a humectant to prevent the gel drying in use.
Such humectants include alkylene glycols. A particularly preferred humectant is propylene glycol~ This agent has the added advantage in easing the dispersion of the - gelling agent in the bulk of the water during preparation.
Suitably the composition may contain from 2 to lO~ of humectant and preferably 3 to 7%.
Most suitably the pH of the composition will be controlled to prevent oxidation of L-cysteine base to cystine which occurs readily in solutions having a pH
value of greater than 8. The suitable range of pH value is from ~ to 87 most suitably from 3 to 6 and preferably ~ to 6.
The pH value of a gel composition may also depend upon the choice of gelling agent and the vi~cosity o~
required for the final gel. Thus, if the pH value is at the higher end of the range a hydroxyethyl cellulose gelling agent may be used and for gels of lower pH
the preferred gelling agent is a polyacrylic acid ligh~ly cross-linked by triallyl sucrose, when for example pH
values of 4 . 5 to 5.5 are employed.
The viscosity of the final gel were measured using a Ferranti-Shirley cone and plate viscometer using the following parameters, 4 cm cone 120 second sweep time 600g cm 1 torque spring 10 rpm speed 25~C temperature , The apparent viscosity at maximum sheer (10 r.p.m.
= 113.7 sec ) is suitably between 30 and 80 poise and is preferably between 60 and 75 poise.
: ~ptionally the compositions of the present invention may also contain other ingredients including perfumes and inert fillers such as titanium dioxide to provide a white rather than colourless gel.
~L2 fi6~
- B -Normally and preferably the water used in ~he composition will be freshly distilled water which has been de-oxygenated by boiling and allowed to cool with filtered 'inert' gas bubbling thr~ugh lt. By 'inert' gas is meant a non-oxidising gas for cysteine, for example carbon dioxide, particularly preferred is nitrogen. It is also envisaged that any type of water for example deonized water, may be used provided it i5 degassed to remove oxygen and maintained thereafter under nitrogen.
L-cysteine and its salts are readily oxidised in aqueous solutions by oxygen dissolved in the water, hence removal of this oxygen and isolation of this solution from air, avoids oxidation of L-~ysteine and its salts.
The particularly favoured form of the composition of the present invention comprises from 2 to 12% of L-cysteine hydrochloride, 1 to 4~ of propylene phenoxetol, 2 to 10% propylene glycol, 0.1 to 5% polyacrylic acid cross-linked by triallyl sucrose, sodium hydroxide solution to give a pH of 5O4 and sufficient water to adjust the volume to lOQ~.
A preferred form of the composition of the present invention comprises from 4 to 8% of L-cysteine, 1.5 60~
to 3% propylene phenoxetol, 5% propylene glycol, 1.5 polyacrylic acid lightly cross-linked with triallyl sucrose, sodium hydroxide solution to adjust the pH of 5 4 and sufficient water to ad3ust the volume to 100%.
Typically the composition of the present ~ r~ e ~
invention will be packed into ~ ~ laquexed aluminium tubes~
In a second aspect ~herefore the invention provides a method of treating acne which comprises applying top.ically to the affected areas an effective amount of I,-cysteine or a, pharmaceutically acceptable salt thereof and propylene phenoxetol. The composition : will be applied topically to the affected area 2 times daily or more frequently if required.
In severe cases it may be desirable to apply the composition to the affected area up to 6 times a day for example 2, 3, 4, 5 or 6 times daily. Generally 2, 3 or 4 applications daily are most convenient and usually 2 or 3 applications will be made. In mild cases a single application per day may be envisaged.
Generally, treatment will last for at least 7 days and r~
1;;~Ç~6~
may proceed for up to 14 to 23 days or even longer if a physician considers it desirable.
In view of the susceptibility of cysteine to oxidation, the skilled ~uorker will be aware that the compositions employed will be free of agents that would oxidise the cysteine.
Although propylene phenoxetol is the preferred anti-bacterial agent in a less favoured aspect alternative anti-bacterial agents may be employed. Thus in a broader aspect the present invention provides a pharmaceutical composition useful in the treatment of acne which composition comprises L~cysteine or a pharmaceutically acceptable salt thereof and an anti-bacterial agent.
Aptly the composition will contain from 0.1 to 15% of I~cysteine or a pharmaceutically acceptable salt thereof.
Suitably the composition will contain from 0.2 -to 2.07o L,cysteine or a pharmaceutically acceptable salt thereof, more suitably will contain 0.25 to 1.5~o and preferably 0.3 to 0.5%, for exa~ple 0.35o, 0.4070 and 0.45/~ Of I,cysteine or a 20 pharmaceutically acceptable salt thereof. Preferably the hydrochloride of L-cys-teine is employed.
The effectiveness of compositions containing such low concentrations of L,cysteine with the antibacterial agent is particularly surprising. Such concen-trations have the added 25 advantage of being particularly friendly towards the skin.
Apt anti-bacterial agents are those which are compatible with L,cysteine. Suitable anti-bacterial agents include quaternary ammonium salts, for example ben~alkonium chloride and propylene phenoxetol. m e preferred anti-bacterial agent is propylene phenoxetol.
The following Examples are illustrative of the invention.
Example 1 An aqueous gel was made containing:
L-cysteine 7.~/~ w/w 210g Propylene phenoxetol 2.5% w/w 75g Propylene glycol 4.5% w/w 135g Carbopol 934P 2.0~o w/w 60g Sodium hydroxide solution to adjust the p~ to 5.4 Distilled water to adjust the volume to 1007o w/w 2520g.
me freshly distilled water was boiled to remove dissolved oxygen and allowed to cool with filtered nitrogen bubbling through. Nitrogen was bubbled through the buIk of the camposition for the entirety of the process including the filling. The Carbopol 934P was dissolved in the water by warming and stirring. Then the water was allowed to cool to ambient tenmperature. l`he propylene phenoxetol was dispersed in the propylene glycol and then added to the cool water with stirring. The L-cysteine was then dissolved in the solution and the p~I adjusted to pH 5.4 using sodium hydroxide solution. The weight of solution was adjusted to the weight re~uired by addition of dea~ygenated water. The resultant solution was mixed for a further 15 minutes under a nitrogen blanket. The resultant clear product was transferred to a tube filling apparatus under a blanket of nitrogen. The product was filled in a conventional manner into araldite lacquered aluminiun ~Ibes which have been flushed with nitrogen.
The tubes were sealed immediately.
The gel was dispensed from the tube as required.
Example 2 - An aqueous gel was made containing:
L,cysteine 8.070 Propylene phenoxetol 2. G7o Propylene glycol 7.0%
C~rbopol 934P 1.25%
Titanium dioxide 0.25,~
Perfume 0.05%
Sodium hydroxide solution to adjust ~I to 5.2 Distilled water to adjust the weight to lOOYo.
The gel was formed and packed using the methods described in Example 1. The titanium dioxide and perfume were added along with the propylene phenoxetol after first mixing with the propylene glycol.
,:
Example 3 An aqueous gel was made containing:
Lrcysteine hydrochloride lO~o Propylene phenoxetol 2 Propylene glycol 6~o Carbopol 934P 2qo Sodium hydroxide solution to adjust the pH to 4.5 Distilled water to adjust the weight to lOOg.
m e gel U~5 prepared and packaged in a si~ilar manner to that described in ~xa~ple 1.
Exa~ple 4 -An aqueous gel was prepared containing:
L,cysteine hydrochloride 0.45qO
Propylene pheno~etol 2.5~
Propylene glycol 6.0,~o Carbopol 934P 1.5~
litanium dioxide 0.25%
Perf~une 0.06,~o Sodium hydroxide solution to adjust the p~l to 5.6 Distilled water to adjust the weight to lOOg.
The gel was forned in a similar manner to that described in Example 2.
~6~
Example 5 An aqueous gel was prepared containing:
L,cysteine 0.35%
Propylene phenoxetol 2.0%
Propylene glycol 7.0%
Carbopol 93~P 1.25%
Perfume 0.0570 Sodium hydl-oxide solution to adjust the pH to 5.2 Distilled water to adjust the weight to lOOg.
m e gel was formed in a similar manner to that described in Example 1.
A clinical trial was carried out on 20 human volunteers suffering from acne. A gel having a formulation described in Example 1 was applied to the effec,ed areas twice a day for 10 weeks.
These areas were inspected after 2, 4, 6, 8 and 10 weeks of treatment. At the end bf 10 weeks the physician conducting the trial concluded that the L-cysteine/propylene phenoxetol gel was an efficacious treatment for acne.
Claims (9)
PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A pharmaceutical composition useful in the treatment of acne which composition comprises L-cysteine or a pharmaceutically acceptable salt thereof and propylene phenoxetol.
2. A composition as claimed in claim 1 which comprises from 0.1 to 15% of L-cysteine or a pharmaceutically acceptable salt thereof.
3. A composition as claimed in either of claims 1 or 2 which comprises from 0.1 to 5% of propylene phenoxetol.
4. A composition as claimed in claim 1 in which the composition is in the form of a self-supporting aqueous gel.
5. A composition as claimed in claim 4 in which the composition comprises from 0.1 to 5% of gelling agent.
6. A composition as claimed in claim 5 in which the gelling agent is polyacrylic acid lightly cross-linked with triallyl sucrose.
7. A composition as claimed in claim 4 which comprises from 2 to 10% of a humectant.
8. A composition as claimed in claim 7 in which the humectant is propylene glycol.
9. A composition as claimed in claim 1 in which the composition has a pH in the range 3 to 6.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB8424957 | 1984-10-03 | ||
| GB848424957A GB8424957D0 (en) | 1984-10-03 | 1984-10-03 | Pharmaceutical compositions |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1266002A true CA1266002A (en) | 1990-02-20 |
Family
ID=10567622
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000492037A Expired CA1266002A (en) | 1984-10-03 | 1985-10-02 | Acne treating composition containing l-cysteine |
Country Status (4)
| Country | Link |
|---|---|
| AU (1) | AU583539B2 (en) |
| CA (1) | CA1266002A (en) |
| GB (1) | GB8424957D0 (en) |
| ZA (1) | ZA857595B (en) |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| ZA702518B (en) * | 1969-04-18 | 1971-01-27 | Bristol Myers Co | Acetylcysteine for acne |
| AU8048882A (en) * | 1981-03-05 | 1982-09-09 | National Foundation For Cancer Research Inc. | Adducts of glyoxal and cysteine as antitumor agents |
-
1984
- 1984-10-03 GB GB848424957A patent/GB8424957D0/en active Pending
-
1985
- 1985-10-02 CA CA000492037A patent/CA1266002A/en not_active Expired
- 1985-10-02 AU AU48207/85A patent/AU583539B2/en not_active Ceased
- 1985-10-02 ZA ZA857595A patent/ZA857595B/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| ZA857595B (en) | 1986-05-28 |
| AU4820785A (en) | 1986-04-10 |
| AU583539B2 (en) | 1989-05-04 |
| GB8424957D0 (en) | 1984-11-07 |
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