Enhancement of Solubility of Raloxifene HCl by Formulating Immediate and Controlled Release Solid Dispersion

For a practically insoluble drug it is extremely challenging to formulate controlled release tablets due to their low solubility. Since solid dispersion with PVP K30 increased the solubility nearly 4 folds, the effect of three different viscosity grade HPMCs on the in vitro dissolution from controlled release tablets was evaluated at four use levels of 10%, 15%, 30% and 45%. The in vitro dissolution testing in the most challenging medium plain water indicated that the drug release is governed by the type and concentration of the polymer and not by the solubility of the drug. Immediate release tablets of Raloxifene HCl solid dispersions were formulated and compared with those of the plain Raloxifene HCl tablets. In vitro dissolution studies of IR tablets also proved that PVP K30 is the best polymer which showed a maximum release of 81% in 1 hour in water as media. For PVP S630 it was 76 % maximum release, when it was 44 % for the plain drug.