FORMULATION AND EVALUATION OF CONTROLLED POROSITY OSMOTIC TABLETS OF LORNOXICAM

The aim of the present study is to formulate and evaluate controlled release formulation of lornoxicam based on osmotic technology. Lornoxicam, a potent non-steroidal anti-inflammatory drug (NSAID) with shorter half life, makes the development of sustained release (SR) dosage forms extremely advantageous. However, due to its weak acidic nature, its release from SR delivery system is limited to the lower GIT which consequently leads to a delayed onset of its analgesic action. Basic pH modifier tromethamine and wicking agent SLS were incorporated into the core tablet to create basic environmental pH inside the tablets, which provide complete drug release that starts in the stomach to rapidly alleviate the painful symptoms and continue in the intestine to maintain protracted analgesic effect. The effect of different formulation variables namely level of osmogen (mannitol) in the core tablet and level of pore former (sorbitol) in the coating membrane on in-vitro release was studied. Lornoxicam release from controlled porosity osmotic pump was directly proportional to the pore former (sorbitol) and level of osmogen (mannitol). Drug release from the developed formulations was independent of pH and agitational intensity and was dependent on osmotic pressure of the release media. Results of SEM studies showed the formation of pores in the membrane from where the drug release occurred. The optimized formulation was found to release the drug in zero order and found to be stable upon stability studies.