Cumulative irritation potential of topical retinoid formulations.
BACKGROUND
Localized irritation can limit treatment success with topical retinoids such as tretinoin and adapalene. The factors that influence irritant reactions have been shown to include individual skin sensitivity, the particular retinoid and concentration used, and the vehicle formulation.


OBJECTIVE
To compare the cutaneous tolerability of tretinoin 0.04% microsphere gel (TMG) with that of adapalene 0.3% gel and a standard tretinoin 0.025% cream.


METHODS
The results of 2 randomized, investigator-blinded studies of 2 to 3 weeks' duration, which utilized a split-face method to compare cumulative irritation scores induced by topical retinoids in subjects with healthy skin, were combined. Study 1 compared TMG 0.04% with adapalene 0.3% gel over 2 weeks, while study 2 compared TMG 0.04% with tretinoin 0.025% cream over 3 weeks.


RESULTS
In study 1, TMG 0.04% was associated with significantly lower cumulative scores for erythema, dryness, and burning/stinging than adapalene 0.3% gel. However, in study 2, there were no significant differences in cumulative irritation scores between TMG 0.04% and tretinoin 0.025% cream. Measurements of erythema by a chromameter showed no significant differences between the test formulations in either study.


CONCLUSIONS
Cutaneous tolerance of TMG 0.04% on the face was superior to that of adapalene 0.3% gel and similar to that of a standard tretinoin cream containing a lower concentration of the drug (0.025%).
Leyden
James J
JJ
Department of Dermatology, University of Pennsylvania Hospital, Philadelphia, PA, USA. jjleyden@mindspring.com
Grossman
Rachel
R
Nighland
Marge
M
D000152:Acne Vulgaris / Q000188:drug therapy*; D000068816:Adapalene; D000287:Administration, Topical; D000328:Adult; D003879:Dermatologic Agents / Q000009:adverse effects*; D005260:Female; D006801:Humans; D007509:Irritants / Q000009:adverse effects; D009281:Naphthalenes / Q000008:administration & dosage / Q000009:adverse effects*; D016032:Randomized Controlled Trials as Topic; D012867:Skin / Q000187:drug effects*; D014212:Tretinoin / Q000008:administration & dosage / Q000009:adverse effects*
D003879:Dermatologic Agents; D007509:Irritants; D009281:Naphthalenes; D000068816:Adapalene; D014212:Tretinoin