Optimization of microencapsulation of metronidazole in alginate microbeads for purpose of controlled release

Abstract

To obtain the optimum conditions for encapsulation of metronidazole in sodium alginate, a response surface methodology (RSM) was used to find out the effect of independent variables (alginate concentration and drug to alginate ratio) on dependent variables including mean particle size, yield, drug loading, and encapsulation efficiency. Furthermore, the effect of alginate concentration on swelling behavior of microbeads was evaluated, and the mechanism of drug release was also studied. On the basis of the results, it can be declared that spherical microbeads with mean particle sizes of 443-665 µm were obtained with process yields, drug loading, and encapsulation efficiencies of almost 79.5%, 54.9%, and 79.9%, respectively. The metronidazole release was found to be 68% in 7 h with a formulation containing the drug to polymer ratio of 2:1. The optimum values for alginate concentration and drug to alginate ratio were determined to be within 1.4% (w/v) and 2.85 (w/w), respectively.