In vitro Hydrolysis of Dexamethasone 21-palmitate

• Published in: Ensho Vol. 5; no. 3; pp. 219 - 223
• Main Authors: Okamoto, Hiroyuki, Watanabe, Masahiro, Ohyanagi, Harumasa, Saitoh, Yohichi
• Format: Journal Article
• Language: Japanese
• Published: The Japanese Society of Inflammation and Regeneration 01.07.1985
• ISSN: 0389-4290; 1884-4006
• DOI: 10.2492/jsir1981.5.219

Dexamethasone 21-palmitate (DP) is a main ingredient of Liposteroid which is an injectable anti-inflammatory preparation, in a form of fat emulsion. DP is considered to be a pro-drug. Many steroid esters used therapeutically are known to be rapidly hydrolyzed in vivo. However, the hydrolysis rate of steroid esters vary with chain length. It is, therefore, very important to know the hydrolysis rate of DP and tissue distribution of hydrolyzing enzymes in relation to its pharmacology, toxicity and metabolism in vivo. The hydrolyzing activities were found in serum, liver and macrophages of rat and also in liver and monocytes of human. The affinity of DP to the enzymes is very low and DP was found to be more slowly hydrolyzed in vitro. DP is likely to be hydrolyzed by non-specific carboxylesterases. These results suggest that DP is hydrolyzed gradually and continuously to dexamethasone and exhibits a more prolonged activity in vivo.