RT Journal Article SR Electronic T1 METABOLISM OF CARBIDOPA [L-(-)-α-HYDRAZINO-3,4-DIHYDROXY-α-METHYLHYDROCINNAMIC ACID MONOHYDRATE], AN AROMATIC AMINO ACID DECARBOXYLASE INHIBITOR, IN THE RAT, DOG, RHESUS MONKEY, AND MAN JF Drug Metabolism and Disposition JO Drug Metab Dispos FD American Society for Pharmacology and Experimental Therapeutics SP 9 OP 22 VO 2 IS 1 A1 S. VICKERS A1 E. K. STUART A1 J. R. BIANCHINE A1 H. B. HUCKER A1 M. E. JAFFE A1 R. E. RHODES A1 W. J. A. VANDENHEUVEL YR 1974 UL http://dmd.aspetjournals.org/content/2/1/9.abstract AB Carbidopa [L-(-)-α-hydrazino-3,4-dihydroxy-α-methylhydrocinnamic acid monohydratel is of interest in the therapy of Parkinson’s disease. After 20 mg/kg (oral), the dog, monkey, and rat excreted 66%, 40%, and 16% of the dose of radioactivity in the urine, respectively. Fecal contents accounted for approximately 11%, 32%, and 52% of the oral dose of radioactivity in the dog, monkey, and rat, respectively. An average 50% of an oral dose (50 mg) of carbidopa-14C was excreted in the urine of humans. Analysis of expired air indicated that there was little decarboxylation of carbidopa-1-14C in either the rat or the human. Approximately 7.5% of an oral dose (20 mg/kg) was excreted in the bile of rats. A tissue distribution study of radioactivity in the rat (20 mg/kg iv) showed that after 1 hr radioactivity was concentrated relative to the plasma in the kidney, lungs, small intestine, and liver. Unchanged carbidopa was excreted in the urine of man, monkey, dog, and rat. α-Methyl-3-methoxy-4-hydroxyphenylpropionic acid and α-methyl-3,4-dihydroxyphenylpropionic acid were detected in the urine of the first three species following enzymic hydrolysis. In addition, 3,4-dihydroxyphenylacetone was identified in human and dog urine. Copyright © 1974 by The American Society for Pharmacology and Experimental Therapeutics