Surface tension lowering and dissolution rate of hydrocortisone from solid solutions of selected n-acyl esters of cholesterol.

The dissolution of hydrocortisone into simulated intestinal fluid from lipid delivery systems followed second-order kinetics. As the ratio of hydrocortisone to lipid was increased from 1:1 to 1:6, the dissolution rate decreased. Solvent deposition of solid solutions of hydrocortisone and lipid on lactose resulted in the enhancement of the dissolution rate. For the 1:1 hydrocortisone-lipid solid solutions, the rank order of the dissolution rate was hydrocortisone-cholesteryl stearate, hydrocortisone, hydrocortisone-cholesterol, hydrocortisone-cholesteryl acetate, hydrocortisone-cholesteryl palmitate, hydrocortisone-cholesteryl n-butyrate, hydrocortisone-cholesteryl laurate, and hydrocortisone-cholesteryl n-decylate. A direct correlation was found between the dissolution rate of hydrocortisone and the surface tension lowering of simulated intestinal fluid by the corticoid and various lipids.