Design and Characterization of Lansoprazole Delayed Release Tables Employing Novel Entric Coating Agents

Abstract

The present study aimed to enhance the solubility and dissolution rate of Lansoprazole through the preparation of solid dispersions using Hydroxypropyl-β-cyclodextrin (HP-β CD) and to further develop sustained release formulations. Solid dispersions of Lansoprazole were prepared by three different methods physical mixture, kneading method, and co precipitation method in varying drug-to-carrier ratios (1:1 and 1:2). Among these, the co-precipitation method demonstrated the highest enhancement in solubility, followed by the kneading method and the physical mixture, indicating the order: Physical mixture < Kneading method < Co-precipitate method. The optimized formulation (CP-2: Drug: HP β-CD at 1:2 ratio by co-precipitation method) exhibited superior solubility enhancement and dissolution performance. Lansoprazole–HP-β-cyclodextrin complexes showed a significantly higher dissolution rate and efficiency compared to pure Lansoprazole and its conventional capsule forms. These optimized solid dispersions were further utilized to formulate sustained release tablets using different grades of HPMC (K4M, K15M, and K100M) as release-retarding polymers. The pre-compression parameters, including angle of repose, bulk density, tapped density, and compressibility index, indicated excellent flow properties suitable for direct compression. Drug release studies revealed that an increase in polymer concentration led to a reduction in the drug release rate, with formulation F8 exhibiting the most desirable sustained release profile. Kinetic modeling confirmed that the drug release followed zero-order kinetics and obeyed the Higuchi diffusion model, indicating a diffusion-controlled release mechanism.