title: The effect of simulated solar UV irradiation on tretinoin in tretinoin gel microsphere 0.1% and tretinoin gel 0.025%.
abstract: Topical tretinoin is highly effective and widely used in the treatment of acne vulgaris. Tretinoin gel microsphere 0.1% (TGM)--alone or in combination with erythromycin-benzoyl peroxide (EBP) or clindamycin-benzoyl peroxide (CBP) topical gels-and tretinoin gel 0.025% (TG)--alone or, combined with EBP-were exposed to simulated solar UV irradiation to determine the degree of tretinoin photodegradation/isomerization. The investigation revealed that 94% and 84% of the initial tretinoin in the TGM formulation remained stable after 2 and 6 hours, respectively, of simulated solar UV irradiation. When combined with EBP topical gel, 89% and 81% of the initial tretinoin remained stable after 2 and 6 hours, respectively, of exposure to simulated solar UV irradiation; 86% and 80% of the tretinoin remained stable after 2 and 6 hours, respectively, when combined with CBP topical gel. In contrast, only 19% and 10% of the tretinoin remained unchanged after 2 and 6 hours, respectively, of simulated solar UV irradiation of TG. Combined with the EBP topical gel, undegraded tretinoin quantities were further reduced to 7% and 0% at 2 and 6 hours, respectively, with TG. These data suggest that the TGM formulation offers marked protection against tretinoin photodegradation compared with TG, even in the presence of a topical gel containing a potent antibiotic or a strong oxidizing agent. Although simulated solar UV irradiation is not entirely reflective of actual conditions, the results appear to be substantial.
authors.affiliation: Johnson & Johnson Consumer and Personal Products Worldwide, Skillman, NJ 08558-9418, USA. mnighla@cpcus.jnj.com
authors.forename: Marge
authors.initials: M
authors.lastname: Nighland
authors.forename: Mohammed
authors.initials: M
authors.lastname: Yusuf
authors.forename: Stephen
authors.initials: S
authors.lastname: Wisniewski
authors.forename: Kate
authors.initials: K
authors.lastname: Huddleston
authors.forename: Judit
authors.initials: J
authors.lastname: Nyirady
mesh_terms: D000900:Anti-Bacterial Agents / Q000008:administration & dosage; D001585:Benzoyl Peroxide / Q000008:administration & dosage; D002981:Clindamycin / Q000008:administration & dosage; D004355:Drug Stability; D004359:Drug Therapy, Combination; D004917:Erythromycin / Q000008:administration & dosage; D005782:Gels; D006801:Humans; D007641:Keratolytic Agents / Q000008:administration & dosage / Q000032:analysis / Q000528:radiation effects*; D008863:Microspheres; D008954:Models, Biological; D014212:Tretinoin / Q000008:administration & dosage / Q000032:analysis / Q000528:radiation effects*; D014466:Ultraviolet Rays
chemical_list: D000900:Anti-Bacterial Agents; D005782:Gels; D007641:Keratolytic Agents; D002981:Clindamycin; D014212:Tretinoin; D004917:Erythromycin; D001585:Benzoyl Peroxide