Inlay osmotic pump tablets containing metformin and glipizide.

The goal of diabetes therapy today is to achieve and maintain as near normal glycemia as possible to prevent the long-term microvascular and macrovascular complications of an elevated blood glucose. A newly developed inlay osmotic pump tablet (IOPT) can deliver glipizide (GLZ) and metformin HCl (MET) gradually in controlled manner. The aim of present investigation was to prepare the IOPT that can deliver >75% of GLZ in 2 h, whereas MET released after 2 h and sustained up to 12 h. In the present work, HP-β-CD was used to modify the solubility of GLZ before incorporating in the osmotic system and MET was spray-dried with HPMC A15C to modify its release profile, flow property, and compressibility. Various parameters mainly G(75%) (75% GLZ release), t(LMET) (lag time of MET release from device), Q(10 h) (percent of MET released within 10 h), and RSQ(ZERO) (R(2) of release data fitted to zero-order equation) were used to compare different formulations. The effects of different formulation variables, that is, osmagents, concentration of hydrophilic polymer, diameter of drug releasing orifice, and coating composition on the drug release profile were investigated. The release rate of GLZ could be effectively modified by the addition of sodium carbonate and sodium chloride, whereas the release rate of MET was adjusted by dual-coating system and by addition of hydrophilic polymer. The developed inlay osmotic system could be effective in the multidrug therapy of diabetes by delivering both drugs in a controlled manner.