Effect of the formulation parameters on the encapsulation efficiency and release behavior of p-aminobenzoic acid-loaded ethylcellulose microspheres

Abstract

In the current study, p-aminobenzoic acid-loaded ethylcellulose microspheres were prepared under various conditions by solvent evaporation method (o/w). This preparation was carried out with different p-aminobenzoic acid:ethylcellulose (PABA:EC) ratios, stirring speed, surfactant nature and concentration in order to investigate their effect on encapsulation efficiency and drug release kinetics. Scanning Electron Microscopy (SEM) studies showed spherical microspheres with a porous surface and different structures. The mean diameter of Sauter (d32) of these microparticles is in the range from 47 to 165 μm with PVA and from 793 to 870 μm with Tween 80 by adjusting process parameters. However, the encapsulation efficiency varied from 37.52 to 79.05 % suitable for the adjustment of a p-aminobenzoic acid with pro-longed release. Microspheres were characterized by FTIR, DSC and XRD. The release of cation of p-aminobenzoic acid was performed in simulated gastric medium at pH 1.2 and 37±0.5°C by UV-VIS analysis to estimate its content. The release data were best fitted to Higuchi model with high correlation coefficient (r²) and the obtained values of n from Korsmeyer-Peppas showed that the drug release follows the Fickian diffusion mechanism.

Keywords

• microparticles
• solvent evaporation method
• diffusion
• drug release
• kinetic modeling