@article {VICKERS9, author = {S. VICKERS and E. K. STUART and J. R. BIANCHINE and H. B. HUCKER and M. E. JAFFE and R. E. RHODES and W. J. A. VANDENHEUVEL}, title = {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}, volume = {2}, number = {1}, pages = {9--22}, year = {1974}, publisher = {American Society for Pharmacology and Experimental Therapeutics}, abstract = {Carbidopa [L-(-)-α-hydrazino-3,4-dihydroxy-α-methylhydrocinnamic acid monohydratel is of interest in the therapy of Parkinson{\textquoteright}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 {\textcopyright} 1974 by The American Society for Pharmacology and Experimental Therapeutics}, issn = {0090-9556}, URL = {https://dmd.aspetjournals.org/content/2/1/9}, eprint = {https://dmd.aspetjournals.org/content/2/1/9.full.pdf}, journal = {Drug Metabolism and Disposition} }