EFFECT OF SUPERSATURATION ON MEMBRANE-TRANSPORT .2. PIROXICAM

Subsaturated, saturated and supersaturated solutions of piroxicam were prepared in a propylene glycol/water cosolvent system. The diffusion of these solutions across a model membrane of Silastic(R) was investig ated. It was shown that in a single cosolvent system the diffusion of the drug was linear with respect to the degree of saturation. However, the results from the flux of supersaturated solutions in different pr opylene glycol/water vehicles showed that there was an increase in the flux of piroxicam as the proportion of propylene glycol was increased . This was also true with the diffusion of saturated solutions across Silastic(R). Further investigations showed that this effect was most l ikely due to the enhanced partitioning of piroxicam into the membrane.