PT  - JOURNAL ARTICLE
AU  - S. Y. YEH
AU  - L. A. WOODS
TI  - PHYSIOLOGIC DISPOSITION OF N-C<sup>14</sup>-METHYL-CODEINE IN THE RAT
DP  - 1969 Mar 01
TA  - Journal of Pharmacology and Experimental Therapeutics
PG  - 86--95
VI  - 166
IP  - 1
4099  - http://jpet.aspetjournals.org/content/166/1/86.short
4100  - http://jpet.aspetjournals.org/content/166/1/86.full
SO  - J Pharmacol Exp Ther1969 Mar 01; 166
AB  - Maximum levels of codeine and its metabolites in plasma and of free codeine in brain appear 15 to 30 min after s. c. adminiRtration of 2 mg/kg (base) of N-C14-methyl-codeine to Sprague-Dawley male rats. Neither free nor conjugated morphine is found in brain. Conjugated codeine is not detectable in either brain or plasma at any time period. The brain/plasma ratio of free codeine is about 2:1. In 24 hr, 7.6%, 18.5% and 17.7% of injected radioactivity is eliminated as C14O2 in expired air from female rats, male rats and male rats with cannulated bile ducts, respectively. Amounts recovered in bile are 1.3% as free codeine, 0.9% as free morphine and 43.1% as conjugated morphine. Percentage recoveries of free codeine, free morphine and conjugated morphine from the respective samples are as follows: urine of male rats with cannulated bile ducts, 62%, 32% and 19.4%; urine of male rats, 7.8%, 7.6% and 23.8%; urine of female rats, 72%, 63% and 44.4%; feces and intestinal content of male rats, 0.8%, 14.3% and 0.0%; feces and intestinal content of female rats, 1.0%, 12.7% and 0.0%. In 24 hr, 94%, 74% and 86% of injected radioactivity is excreted via pulmonary, biliary, intestinal and urinary routes by male rats with cannulated bile ducts, male rats and female rats, respectively. Twenty-four hours after injection, about 2% of administered radioactivity is retained in the body. Metabolites in urine and bile have been identified by paper chromatography. © 1969, by The Williams & Wilkins Company