D-optimal designing and optimization of long acting microsphere-based injectable formulation of aripiprazole.

This work was aimed to design and optimize a long acting microsphere-based injectable formulation of aripiprazole by using D-optimal experimental design methodology. Microspheres were prepared by solvent evaporation method using PLGA and cholesterol as release rate retardant materials. The microspheres were characterized for their encapsulation efficiency, particle size, surface morphology, residual solvent content, and drug release behavior. Contour plots were plotted to study the encapsulation and release behaviour of the drug from the microspheres. Desirability technique was used for the optimization of microsphere formulation composition. By using an optimum blend of drug and cholesterol in the microsphere formulation it was possible to attain a consistent drug release for a period of 14 days. The results have confirmed that the D-optimal experimental design technique can be successfully employed for designing the long acting microsphere dosage form.