Drug release optimization from microparticles of poly(E-caprolactone) and hydroxypropyl methylcellulose polymeric blends: formulation and characterization

In this study, polymeric blend microparticles are prepared with tunable drug releasing behavior, imparted by using poly(e-caprolactone) (PCL) as hydrophobic and hydroxypropyl methylcellulose (HPMC) as hydrophilic biodegradable polymeric constituents. Microparticles were prepared by simple oil in water emulsion-solvent evaporation method and evaluated for their sustained release profile by using nifedipine (half-life is about 2 h) as model drug. Hydrophilic PCL is added to optimize the drug release in simulated aqueous body fluid. Polyvinyl alcohol (PVA), used as emulsifier, was found to improve shape while HPMC increased surface smoothness of microparticles. High encapsulation efficiency was achieved, controllable by HPMC concentration. In vitro dissolution studies in acidic and neutral pH showed sustained release profile for all formulations. Synthesized microparticles, provided control over hydrophobic drug release by changing the proportion of HPMC and PCL in formulation at both acidic and intestinal pH.