Release of rooperol tetra-acetate from topical bases: in vitro studies using silicone membrane

The influence of the vehicle on the delivery of rooperol tetra-acetate, a lipophilic drug, from a gel, oil-in-water, water-in-oil and ointment vehicle was investigated using an in vitro membrane permeation system. Diffusion studies were performed under occluded and unoccluded conditions using polydimethylsiloxane membrane. The results obtained showed that after 8 h of diffusion, the occluded and unoccluded gel systems, followed by the occluded and unoccluded oil-in-water systems most effectively promoted the delivery of rooperol tetra-acetate. The mean calculated flux rate was 22.50 +/- 4.65 mg/cm(2) per h from the occluded gel vehicles compared to 8.23 +/- 3.23 mg/cm(2) per h from the occluded oil-in-water vehicle. The remaining two systems studied exhibited lower flux rates with the ointment base showing the least drug release. The data obtained fi-om the in vitro permeation studies performed here call be used as a predictive model for the release characteristics of rooperol tetra-acetate from topical vehicles. (C) 1998 Elsevier Science B.V.