Release of testosterone from an osmotic pump tablet utilizing (SBE)(7m)-beta-cyclodextrin as both a solubilizing and an osmotic pump agent

A controlled porosity osmotic pump system for poorly water soluble drugs ha s been developed using sulfobutyl ether-beta-cyclodextrin sodium salt, (SBE )(7m)-beta-CD, which can act as both a solubilizing and an osmotic agent. T he release of testosterone, a poorly water soluble drug (0.039 mg/ml at 37 degrees C), was evaluated using a new model device. The effect of (SBE)(7m) -beta-CD as the solubilizing and osmotic pump agent was compared with hydro xypropyl-beta-cyclodextrin (HP-beta-CD), a neutral cyclodextrin, and a suga r mixture (osmotic agent only). Testosterone release from the device was si gnificantly faster with (SBE)(7m)-beta-CD than with HP-beta-CD or the sugar mixture. The solubility of testosterone in the device increased to 76.7 mg /ml through complexation with (SBE)(7m)-beta-CD in the imbibed water. it ap pears that testosterone release from the device in the presence of (SBE)(7m )-beta-CD was mainly due to osmotic pumping while for HP-beta-CD the major contribution appears to be due to diffusion. In the case of the sugar mixtu re, testosterone was poorly released, presumably due to the absence of a so lubilizer. Therefore, it was concluded that (SBE)(7m)-beta-CD provides nove l properties for the development of controlled-porosity osmotic pump tablet s for poor solubility drugs. (C) 1999 Elsevier Science B.V. All rights rese rved.