Carnitine and glucuronic acid conjugates of pivalic acid

1. The 1-¹⁴C]pivaloyloxyethyl ester of methyldopa administered to man and cynomolgus monkeys resulted in the elimination in the urine of ¹⁴C-pivalic acid metabolites.

2. Pivaloyl glucuronide and pivaloyl carnitine were identified as the major radioactive urinary metabolites in monkey urine and human urine, respectively.

3. N.m.r. analysis indicated that pivaloyl carnitine had a cyclic structure.

4. Although the role of carnitine is in the transport of fatty acids across mitochondrial membranes, it may also function in the conjugation of carboxylic acid xenobiotics in humans.