4-ACETAMIDOPHENYL 2,2,2-TRICHLOROETHYL CARBONATE SYNTHESIS PHYSICAL PROPERTIES AND IN VITRO HYDROLYSIS

A trichloroethyl carbonate prodrug ester of acetaminophen has been made by reacting acetaminophen with trichloroethyl chloroformate. It is a virtually tasteless crystalline compound retaining the pharmacologic effects of acetaminophen and trichloroethanol. It is lipophilic; its solubility in water is less than 0.05%. It undergoes base‐catalyzed hydrolysis, and at pH 7.4 has a half‐life in water solution of about 7 hr. Its stability in the solid state makes this compound amenable to use in dosage forms such as tablets and capsules. Hydrolysis of this compound is not catalyzed by human gastric fluid, but it is catalyzed by human intestinal fluid, rat intestinal mucosa, rat plasma, rat liver, and human plasma. It was surmised, therefore, that following oral administration to animals, a portion of the prodrug may be absorbed intact, but some cleavage may occur before and during absorption from the intestines. Furthermore, since enzymes that hydrolyze it are prevalent in plasma and liver, the prodrug on entering the blood will be hydrolyzed very rapidly. Copyright © 1968 Wiley‐Liss, Inc., A Wiley Company