The aim of the present investigation was to develop Monolithic Osmotic Tablet System (MOTS) of pH dependent and poorly water soluble lornoxicam (LOR) for controlled drug release. MOTS of LOR comprised freeze dried ternary amorphous complex of drug as core and cellulose acetate with pore former as release controlling membrane. LOR has a poor water (61 μg/ml) and pH dependant (3 μg/ml in pH 1.2) solubility. Freeze dried amorphous ternary complex of drug containing β-cyclodextrin and arginine (LOR:β- CD:Arg) in stoichiometry ratio of 1:1:1 was found to give 30 fold and 300 fold increase in solubility of LOR in water and in 1.2 pH buffer respectively as compared to plane drug which is prerequisite for MOTS. Amorphization of LOR was confirmed by XRD, DSC and SEM study. LOR has a half-life of 3-4 hr which necessitates developing controlled release system of drug for longer period of time. Different formulation variables like type of polyethylene oxide, concentration of pore former, coating weight gain, concentration of osmotic agent and aperture diameter were optimized to achieve zero order drug release. Optimized MOTS of LOR was found to be delivering drug at controlled zero order rate up to 24 hr. pH independent controlled drug release behaviour was revealed by carrying out dissolution in 1.2 pH, 4.5 pH and 6.8 pH dissolution medium. Hence, the developed monolithic osmotic system of LOR utilizing freeze dried amorphous ternary complex was found to be promising approach for controlled release of pH dependent and poorly water soluble drug candidates.

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