A Rapid Tool to Optimize Process Variables for Continuous Manufacturing of Metronidazole Ointment Using Melt Extrusion Technique

The use of hot-melt extrusion (HME) technique in the preparation of semi-solid products offers several advantages over conventional processes. However, the optimization of the technique for preparation of semi-solid pharmaceuticals is challenging due to involvement of ingredients with different physical properties. Hence, a simple tool to optimize the mixing of ingredients that results in a target ratio and drug content uniformity is utmost important. In this study, a handheld colorimeter has been explored to optimize the process variables of twin screw processor for preparation of hydrophilic PEG-based ointment. The process parameters which were optimized with use of handheld colorimeter have been used for preparation of polyethylene glycol-based metronidazole ointment. The metronidazole ointment prepared by twin screw processor was compared with commercially available metronidazole gel forin vitrorelease testing andex vivopermeation. The flux,ex vivobioavailability, andT(max)of polyethylene glycol-based metronidazole ointment was found to be similar to that of marketed metronidazole gel.