抄録
Hydrocortisone 21-o-sulfobenzoate (II), hydrocortisone 21-m-sulfobenzoate (III), and hydrocortisone 21-sulfate (IV) were synthesized. II is solubilized in an alkaline region, while III and IV are solubilized over a wide range of pH. Kinetic examination of the hydrolysis reaction of II and III in an aqueous solution indicated that both undergo decomposition of the first order. The pH profile of the decomposition rate constants of these derivatives showed that, in the alkaline region, decomposition reaction due to the catalyst effect of the hydroxyl ion is the most dominant. III is the most stable at around pH 3. The rate constant of IV was found to be the minimum at around pH 5-6 from the pH profile of its decomposition rate constant. Effect of ionic strength and temperature on the hydrolysis rate constants of these derivatives were examined, and pharmacological activities of 12 kinds of hydrocortisone 21-ester were compared.
