Kinetics and dose-response of photosensitivity in cream psoralen plus ultraviolet A photochemotherapy: comparative in vivo studies after topical application of three standard preparations

Citation
M. Grundmann-kollmann et al., Kinetics and dose-response of photosensitivity in cream psoralen plus ultraviolet A photochemotherapy: comparative in vivo studies after topical application of three standard preparations, BR J DERM, 144(5), 2001, pp. 991-995
Citations number
25
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Dermatology,"da verificare
Journal title
BRITISH JOURNAL OF DERMATOLOGY
ISSN journal
0007-0963 → ACNP
Volume
144
Issue
5
Year of publication
2001
Pages
991 - 995
Database
ISI
SICI code
0007-0963(200105)144:5<991:KADOPI>2.0.ZU;2-T
Abstract
Background Topical photochemotherapy with bath psoralen plus ultraviolet (U V) A irradiation (PUVA) has been developed to reduce possible side-effects of oral PUVA therapy. Although the efficacy of bath PUVA therapy appears to be similar to oral PUVA therapy, provision of bathing facilities has obvio us economic, logistic and sanitary implications. Cream PUVA therapy has rec ently been developed as a variation of topical PUVA. Objectives To understand the photobiological effects and to increase the sa fety and effectiveness of this novel topical PUVA therapy, we assessed the kinetics and dose-response of phototoxicity of 8-methoxypsoralen (8-MOP) cr eam in order to develop a treatment schedule for this treatment option. Methods Ninety-eight patients (63 men and 35 women) undergoing cream PUVA t herapy were studied. The phototoxic properties of topically applied 8-MOP i n three different water-in-oil creams as vehicles were assessed. In a dose- response study, four concentrations of 8-MOP cream (0.0006-0.005%) were use d for determination of the minimal phototoxic dose (MPD). The kinetics of p hotosensitization were tested by determination of MPDs after different appl ication times of 8-MOP cream (10, 20, 30 and 60 min). The persistence of ph ototoxicity was assessed by UVA exposure at defined time intervals after ap plication of 8-MOP cream (0, 30, 60 and 120 min). Results The concentration required to produce sufficient but not undue phot osensitization of the skin was 0.001% 8-MOP. The duration of application le ading to the lowest MPD was 30 min. Greatest photosensitization was achieve d when UVA irradiation was performed between 0 and 30 min after 8-MOP remov al. These findings showed no significant difference between the three vehic les used. Conclusions Based on our data we recommend application of 0.001% 8-MOP in a water-in-oil cream for 30 min. Irradiation with UVA should be performed wi thin 30 min after removal of 8-MOP cream, as there is a rapid decrease in p hotosensitivity thereafter.