Keratolytic activity of microemulsions.
OBJECTIVE
To compare the keratolytic activities of a drug-free hydrophilic microemulsion (ME) and a drug-free lipophilic ME with water, and with regard to the hydrophilic ME also with a 5% salicylic acid gel on the sole of the foot.


METHODS
Twenty healthy volunteers had their plantar forefoot, midfoot, and rearfoot stratum corneum blackened with silver nitrate and a photographic developer, and a chromameter was used to determine the extent of removal of this black dye by a* value and L value measurement at 24 and 48 h.


RESULTS
Both drug-free MEs produced significantly greater increases in a* value and L value than water, and the hydrophilic ME was also more effective than 5% salicylic acid gel.


CONCLUSIONS
The irritating effect of MEs is rather negligible on the sole of the foot because of the thick plantar stratum corneum. Both MEs therefore appear suitable for the elimination or prevention of plantar desquamative and hyperkeratotic skin changes.
Gloor
M
M
Department of Dermatology, Karlsruhe Municipal Medical Center, Karlsruhe, Germany. mgloor@onlinehome.de
Haus
G
G
Keipert
S
S
D000279:Administration, Cutaneous; D000293:Adolescent; D000328:Adult; D002626:Chemistry, Pharmaceutical; D004075:Diglycerides / Q000008:administration & dosage / Q000494:pharmacology; D004655:Emulsions / Q000008:administration & dosage / Q000494:pharmacology*; D004817:Epidermis / Q000187:drug effects; D005260:Female; D005528:Foot; D005782:Gels; D005990:Glycerol / Q000008:administration & dosage / Q000031:analogs & derivatives / Q000494:pharmacology; D006801:Humans; D007641:Keratolytic Agents / Q000008:administration & dosage / Q000494:pharmacology*; D008297:Male; D009226:Myristates / Q000008:administration & dosage / Q000494:pharmacology; D019301:Oleic Acid / Q000008:administration & dosage / Q000494:pharmacology; D009829:Oleic Acids; D010316:Particle Size; D011092:Polyethylene Glycols / Q000008:administration & dosage / Q000494:pharmacology; D019946:Propylene Glycol / Q000008:administration & dosage / Q000494:pharmacology; D020156:Salicylic Acid / Q000008:administration & dosage / Q000494:pharmacology; D013395:Sucrose / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000494:pharmacology
D004075:Diglycerides; D004655:Emulsions; D005782:Gels; D007641:Keratolytic Agents; D009226:Myristates; D009829:Oleic Acids; C480531:polyglyceryl-6-dioleate; C480598:polyoxyethylene glycerol monostearate; C018152:sucrose monolaurate; C008205:isopropyl myristate; D019301:Oleic Acid; D011092:Polyethylene Glycols; D013395:Sucrose; D019946:Propylene Glycol; D020156:Salicylic Acid; D005990:Glycerol