Pulse photodynamic treatment of acne

Abstract

A pulse photodynamic therapy (or pulse PDT) treatment of acne is described herein.

1 . A method of treating acne in an animal, the method comprising treating the acne by photodynamic therapy (PDT), wherein a photosensitizer is applied to the skin of the animal after a pretreatment of the skin. 
     
     
         2 . The method according to  claim 1 , wherein the photosensitizer is applied for a duration of from 4 minutes to 4 hours. 
     
     
         3 . The method according to  claim 2 , wherein the duration is from 15 minutes to 3 hours. 
     
     
         4 . The method according to  claim 1 , wherein the photosensitizer is applied for a short period of time. 
     
     
         5 . The method according to  claim 4 , wherein the short period of time is from 5 minutes to 120 minutes. 
     
     
         6 . The method according to  claim 4 , wherein the short period of time is from 15 minutes to 60 minutes. 
     
     
         7 . The method according to  claim 4 , wherein the short period of time is from 20 minutes to 40 minutes. 
     
     
         8 . The method according to  claim 4 , wherein the short period of time is selected from the group consisting of 25, 26, 27, 28, 29, 30, 31, 32, 33, 34 and 35 minutes. 
     
     
         9 . A method of treating acne in an animal, the method comprising treating the acne by photodynamic therapy (PDT), wherein a photosensitizer is applied for a short period of time. 
     
     
         10 . The method according to  claim 9 , wherein the short period of time is from 5 minutes to 120 minutes. 
     
     
         11 . The method according to  claim 9 , wherein the short period of time is from 15 minutes to 60 minutes. 
     
     
         12 . The method according to  claim 9 , wherein the short period of time is from 20 minutes to 40 minutes. 
     
     
         13 . The method according to  claim 9 , wherein the short period of time is selected from the group consisting of 25, 26, 27, 28, 29, 30, 31, 32, 33, 34 and 35 minutes. 
     
     
         14 . The method according to  claim 1 , wherein the method reduces side effects associated with PDT. 
     
     
         15 . The method according to  claim 1 , wherein the PDT includes a photoactivation achieved by a natural light source. 
     
     
         16 . The method according to  claim 15 , wherein the PDT includes a photoactivation for a duration of from 0.5 hour to 3 hours with the natural light source. 
     
     
         17 . The method according to  claim 15 , wherein the natural light source is sunlight. 
     
     
         18 . The method according to  claim 1 , wherein the PDT comprises:
 a) subjecting the skin of the animal to a pretreatment;   b) administering to the animal a composition comprising the photosensitizer for a duration of from 5 minutes to 120 minutes; and   c) photoactivating the photosensitizer for a duration of from 0.5 hour to 3 hours with natural light.   
     
     
         19 . The method according to  claim 18 , wherein the pretreatment is mechanical or chemical pretreatment. 
     
     
         20 . The method according to  claim 1 , wherein the PDT comprises:
 a) subjecting the skin of the animal to a pretreatment;   b) administering to the animal a composition comprising the photosensitizer for a duration of about 30 minutes;   c) removing the photosensitizer; and   d) photoactivating the photosensitizer 2.5 hours later for a duration of at least 2 hours with natural light.   
     
     
         21 . The method according to  claim 20 , wherein the pretreatment is mechanical or chemical pretreatment. 
     
     
         22 . The method according to  claim 21 , wherein the pretreatment is sandpaper. 
     
     
         23 . The method according to  claim 20 , wherein the photosensitizer is administered for a duration selected from the group consisting of 27, 28, 29, 30, 31 and 32 minutes. 
     
     
         24 . The method according to  claim 23 , wherein the duration is 30 minutes. 
     
     
         25 . The method according to  claim 1 , wherein the photosensitizer is selected from the group consisting of 5-ALA, 5-ALA derivatives, 5-MAL derivatives, and compounds covered by general formula I:
   R 2   2 N—CH 2 COCH 2 —CH 2 CO—OR 1   (I)
   wherein:   R 1  represents a substituted or unsubstituted straight, branched or cyclic alkyl group; and each R 2  independently represents a hydrogen atom or an optionally substituted alkyl group; and pharmaceutically acceptable salts thereof.   
     
     
         26 . The method according to  claim 25 , wherein R 1  is a substituted or unsubstituted straight-chained alkyl group. 
     
     
         27 . The method according to  claim 1 , wherein the photosensitizer is 5-ALA or 5-methyl ALA ester. 
     
     
         28 . The method according to  claim 1 , wherein administering to the animal of a composition comprising the photosensitizer is carried out with or without occlusion. 
     
     
         29 . The method according to  claim 28 , wherein the administration of the photosensitizer is carried out with occlusion. 
     
     
         30 . The method according to  claim 1 , wherein the pretreatment is selected from the group consisting of mechanical pretreatment and chemical pretreatment. 
     
     
         31 . The method according to  claim 30 , wherein the mechanical pretreatment is dermoabrasion or microneedling. 
     
     
         32 . The method according to  claim 30 , wherein the chemical pretreatment is peeling.