No abstract

The objective was to prepare an Enalapril Maleate (EnM)-loaded floating microsphere with minimum particle size, maximum drug loading, and drug entrapment efficiency. Formulations were prepared by varying drug-to-polymer ratio (A), solvent ratio (B), and stirring time (C). The solvent evaporation method was used to prepare the microsphere. "Box-Behnken's design" (3 factors × 3 levels) was utilized for optimization. The independent variables were polymerto-drug ratio (A), solvent ratio (B), and stirring time (C), while particle size (R 1 ), drug loading (R 2 ), and entrapment efficiency (R 3 ) were considered as dependent variables. EnM-loaded alcohol microsphere (Formulation-A) was prepared and optimized. Both Formulation-A and EnM-loaded acetonitrile microspheres (Formulation-B) were subjected to morphological, micrometric, characterization, and in vitro release studies. The particle size, drug loading, and entrapment efficiency of Formulation-A and Formulation-B were 143 ± 27.75 µm, 37.31% ± 5.73%, and 76.89% ± 4.97%, and 158.13 ± 25.1 µm, 40.13% ± 6.12%, and 99.19% ± 1.14%, respectively. The cumulative drug releases of Formulation-A and Formulation-B were 90.52% ± 4.11% and 86.23% ± 3.81%, respectively. Both formulations followed the Higuchi model of drug release. EnM-floating microsphere was effectively prepared and both formulations showed excellent continuous release properties for more than 12 hours.