E. R. Garrett, M. Royer
May 1, 1962
Citations
0
Influential Citations
2
Citations
Journal
Journal of pharmaceutical sciences
Abstract
Since alkyl substitution on the mono-esterified dicarboxylic acid of 21-steroid hemi-esters decreases the rate of specific hydroxyl ion catalyzed hydrolysis, the kinetics of aqueous hydrolysis of prednisolone and 6α-methylprednisolone hemi-β,β′-dimethylglutarates have been studied by constant pH titration. The effect of steroid 6α-substitution on rate of 21-ester hydrolysis has been indicated. The stabilities of sodium salts of such esters at various pH values between 8 and 10 and at various temperatures have been predicted. It has been shown that steric hindrance due to alkyl substitution on the monoesterified dicarboxylic acid increases stability by more than tenfold over the previously reported stability of the nonhindered hydrocortisone hemisuccinate. A more precise procedure for constant pH titration is described.