Influence of the oil phase dispersion in a cream base on the in vivo release of betamethasone 17-valerate

Abstract

Release of betamethasone valerate (betamethasone 17-valerate) from 3 extemporaneous cream formulations (1 control, 1 containing propylene glycol, and 1 containing \b/-cyclodextrin) and a commercial cream formulation (Betnovate) was compared using the human skin blanching assay in 12 healthy male volunteers. All 3 extemporaneous formulations showed similar drug release rates, equivalent to or better than the commercial preparation containing betamethasone in a 10 fold higher concentration. Electron microscopic examination showed considerably finer dispersion of the oil phase in the extemporaneous formulations. It was concluded that the increased surface area available for partitioning of betamethasone between the cream and the skin is responsible for the improved topical availability of the drug from the extemporaneous formulations