Study of the Effect of Poly(ethylene glycol) on the Nifedipine Microencapsulation and Release

Nifedipine is a dihydropyridine derivate calcium channel blocker, suitable as first-line therapy for patients with hypertension. When blood pressure is high, nifedipine will prevent calcium to pass into cardiac and vascular smooth muscle cells. Nonetheless, nifedipine has a low elimination half-life that makes nifedipine needs to be consumed repeatedly to enhance its bioavailability, and thus, gives rise to nifedipine concentration in blood. Hence, a controlled drug delivery system is needed wherein the drug could be delivered at the desired time. One of the options in drug delivery is drug microencapsulation using a polymer as a coating material. In this study, nifedipine was coated with poly(D-L lactic acid) (PDLLA)/poly(ethylene glycol) (PEG) polyblend also polycaprolactone (PCL)/PEG polyblend using solvent evaporation technique. The effect of the mass composition of the polyblend and molecular weight of PEG on the encapsulation efficiency and drug release was investigated. Microcapsules with the variation of PDLLA/PEG and PCL/PEG composition and PEG molecular weight had an encapsulation efficiency of about 90%-92%. Microcapsules with PDLLA/PEG₆₀₀ (9/1) exhibited the highest drug release of 43.2% with an encapsulation efficiency of 91.96% whereas microcapsules with PCL/PEG₄₀₀ (7/3) had the highest drug release of 44% with an encapsulation efficiency of 90.64%.