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

A controlled porosity osmotic pump system for poorly water soluble drugs has been developed using sulfobutyl ether-β-cyclodextrin sodium salt, (SBE) 7m-β-CD, which can act as both a solubilizing and an osmotic agent. The release of testosterone, a poorly water soluble drug (0.039 mg/ml at 37°C), was evaluated using a new model device. The effect of (SBE) 7m-β-CD as the solubilizing and osmotic pump agent was compared with hydroxypropyl-β-cyclodextrin (HP-β-CD), a neutral cyclodextrin, and a sugar mixture (osmotic agent only). Testosterone release from the device was significantly faster with (SBE) 7m-β-CD than with HP-β-CD or the sugar mixture. The solubility of testosterone in the device increased to 76.7 mg/ml through complexation with (SBE) 7m-β-CD in the imbibed water. It appears that testosterone release from the device in the presence of (SBE) 7m-β-CD was mainly due to osmotic pumping while for HP-β-CD the major contribution appears to be due to diffusion. In the case of the sugar mixture, testosterone was poorly released, presumably due to the absence of a solubilizer. Therefore, it was concluded that (SBE) 7m-β-CD provides novel properties for the development of controlled- porosity osmotic pump tablets for poor solubility drugs.