Abstract

Purpose:To establish a method for preparing protein microspheres for oral administration. Methods: Using bovine serum albumin (BSA) as a model protein and alginate and chitosan as carrier materials, BSA loaded alginate/chitosan microspheres were prepared by a modified emulsifying-gelatinization method. The influence of the preparation conditions on the encapsulation efficiency, drug loading and yield of the microspheres was investigated by an orthogonal design method and the optimal process parameters were obtained. The in vitro release of BSA from the alginate/chitosan microspheres was investigated in 0.1 M HCl solution (pH 1.2) and PBS (pH 7.4) as the release media. Results: The optimal process parameters for the preparation of BSA loaded alginate/chitosan microspheres were obtained. The concentrations of alginate solution, CaCl2 solution and chitosan solution were 1.5% (w/v), 6% (w/v) and 2% (w/v), respectively, and the cross-linking time was 10 min. The mean particle size of the microspheres was 3 μm, the encapsulation efficiency was 81.4±1.5%, and the drug loading was 6.4%±0.1%. The in vitro release of BSA from the alginate/chitosan microspheres prepared with the optimal process showed that the initial burst release was marked both in 0.1 M HCl solution (pH 1.2) and PBS (pH 7.4). The release in PBS (pH 7.4) was faster than that in 0.1 M HCl solution (pH 1.2). Conclusion: The modified emulsifying-gelatinization method is suitable for the preparation of protein-loaded microspheres for oral administration.


Keywords:  Microspheres   Chitosan   Alginate   Bovine serum albumin