Plasma concentrations of betamethasone after topical application of betamethasone 17‐valerate: comparison with oral administration.

Abstract

Plasma concentrations of betamethasone were measured by r.i.a. after oral administration of 0.6 mg betamethasone and topical application of betamethasone 17‐valerate in the same five healthy subjects. Betamethasone 17‐valerate was prepared as a suspension in medical grade pressure sensitive adhesive and applied to a 100 cm2 area on the back for 28 h. Mean maximum plasma concentrations were 5.0 and 0.24 ng ml‐1 and mean AUC values were 75.4 and 7.74 ng ml‐1 h after oral and topical administrations, respectively. The mean plasma elimination half‐life of betamethasone after the removal of topical betamethasone 17‐valerate was 16.6 h which was twice that after oral administration, 8.1 h. Betamethasone 17‐valerate may require application to the skin more than twice daily. 1994 The British Pharmacological Society