Effect of polyblend poly(D,L-lactic acid) and polycaprolactone composition in captopril microcapsule on the encapsulation efficiency and in vitro dissolution test

Captopril is one of the angiotensin-converting enzyme (ACE) class hypertension drugs that has been considerably applied to treat hypertension and congestive heart failure. Captopril has a short half-life of 1.6-1.9 hours. The short half-life of captopril makes captopril needs to be consumed repeatedly. Microencapsulation techniques can be used to cover the lack of captopril. Captopril microcapsules were made using biodegradable polymers, namely poly(D,L-lactic acid) with polycaprolactone as coating using double emulsion (w/o/w) solvent evaporation method with span 80 and tween 80 as surfactant. Microcapsules were made by varying the composition of the polymers in polyblend to study the effect on encapsulation efficiency, surface properties and in vitro dissolution test at pH 1.2 and pH 7.4. The microcapsules were all spherical and had a smooth surface as more PCL was added to the composition in polyblend. Percent yield of microcapsules obtained was about 87 % with an average size of 0.480-0.516 μm. The results of the encapsulation efficiency were 4.94-20.69 %. In the dissolution test of each polyblend composition, microcapsules could withstand the release of captopril for 55 h. The highest drug release was 75 % for the composition of PDLLA/PCL 40:60 (% w/w) was caused by degradation of the polyblend matrix. While the composition of 20:80 (% w/w) and 30:70 (% w/w) captopril was released about 43 % and 46 % through the diffusion process. These results of polyblend PDLLA/PCL as coating material may suggest the potential as a drug delivery system for captopril.