In vitro Preparation and Evaluation of Sustained-Release Microcapsules of Salvianolic Acid

Objective This study aims to investigate the preparation of sustained-release microcapsules of salvianolic acid. Methods The stability of salvianolic acid microcapsules was improved, and the time of action was prolonged in the present study. This was prepared using the spray-drying method, with chitosan as the carrier. In the preparation process, the prescription and process were optimized by L9 (34) using an orthogonal design, with yield and drug loading as indexes, in order to obtain optimum conditions. Results The optimal process and prescription for the preparation of salvianolic acid microcapsules were found to be as follows: mass concentration of chitosan, 1.5%; mass ratio of salvianolic acid to chitosan, 1:3; inlet air temperature, 190°C; and peristaltic pump speed, 300 mL·h-1. The surface of the microcapsules was round, the drug loading was 25.99% ± 2.14%, the yield was 51.88% ± 2.84%, the entrapment efficiency was 86.21% ± 2.89%, and the average particle size was 105.6 ± 2.56 nm. The microcapsules in vitro had certain sustained release characteristics. The internally fitted first-order release model equation was ln(1-Q) = -0.236 t + 4.591 7, r = 0.920. In addition, the results of differential scanning calorimetry show that the properties of salvianolic acid were not changed by the microcapsules. Conclusion Sustained-release microcapsules of salvianolic acid can be successfully prepared by adopting marine polysaccharide as a carrier.