Complexation of aspirin with potato starch and improvement of dissolution rate by dry mixing.

Abstract

Dry mixing of aspirin with potato starch in a centrifugal rotating mixer produced a novel powder, composed of potato starch particles with an aspirin layer adhering on their surfaces. Friction and collision which occurred in the dry mixing process micronized and spread aspirin over the potato starch surfaces, forming a thin aspirin layer. The powder gave a higher rate of aspirin dissolution than a physical mixture. It was suggested from powder X-ray diffractometry, differential scanning calorimetry, and contact angle measurements that the improvement of dissolution rate was caused by an increase in wettability and an increase in the available surface area aspirin.