Design of experiments assisted the development of inclusion complexes of ramipril using hydrophilic carriers for enhancement of solubility and dissolution rate

The goal of the present study was to develop inclusion complexes and polymers dispersions of ramipril prepared by physical mixing, kneading, co-evaporation, and solvent evaporation methods to enhance drug solubility and dissolution rate, and thereby to reduce drug dose and side effects using selected hydrophilic carriers such as beta-CD, PVP-K25, PEG 4000, and HPMC K100M. The prepared formulations were characterized for solubility and in-vitro drug release studies. The systematic optimization of formulations was performed using I-Optimal experimental design by selecting factors such as type of carriers (X1), drug: carrier ratio (X2), and method of preparation (X3), and response variables including percent yield (Y1), solubility (Y2), Carr's index (Y3) and drug release in 30 min (Y4). Mathematical modeling was carried out using a quadratic polynomial model. The inclusion complex formulation (F27) was selected as an optimized batch by numerical desirability function and graphical optimization with the help of design space. The inclusion complex prepared by the co-evaporation method showed maximum drug solubility and released in pH 6.8 phosphate buffer compared to pure and other formulations. The inclusion complex is a feasible approach to improve the solubility, dissolution rate, bioavailability, and minimization of drugs' gastrointestinal toxicity upon oral administration of ramipril.