Influence of the physicochemical properties and concentration of native and modified potato starch on the release of a hydrophobic drug from hard gelatin capsules.

The influence of the physicochemical properties and concentration of potato starch and sodium starch glycolate on the release of phenacetin from hard gelatin capsules is examined. Smaller quantities of sodium starch glycolate are necessary to improve the disintegration of the encapsulated powder mass and the drug release, compared to blends with potato starch. From the ratio of the absolute particle diameter increase to the mean pore diameter of the encapsulated powder mass no prediction about capsule disintegration could be made, contrary to tablets. A better correlation seems to exist between the total volume increase of the starch grains and the disintegration time of the formulation.