Preparation and Characterization of Atenolol Microparticles Developed by Emulsification and Solvent Evaporation

It is believed that controlling the drug release at the site of absorption could improve the bioavailability or in vivo performance of atenolol. Therefore, the aim of the present study was to develop atenolol microcapsules that may improve its absorption and bioavailability via controlling the drug release. The effect of drug:polymer ratio and surfactant concentrations on microcapsules particle size, poly-dispersity, release rate and encapsulation efficiency were investigated. Atenolol microcapsules were prepared by emulsion solvent evaporation technique and factors affecting the formation of the microcapsules were studied. The results showed that as drug:polymer ratio decreased from 3:1 to 1:3, the mean diameter of the microcapsules increased from 524.56 to 749.63 mu m, as well as the encapsulation efficiency improved from 36.87 to 98.52%, while the atenolol release rate decreased. Increasing the concentration of Span 80 from 0.5 to 1.5% decreased the mean diameter of microcapsules from 600.96 to 413.43 mu m, while there was a reduction in the encapsulation efficiency and an increase in the atenolol release rate was observed. In conclusion, the results showed that it is possible to achieve a high drug loading efficiency (up to 98%) with desired properties by changing the parameter involved in the formation of microcapsules.