Comparative study on the metabolism of optical gossypol in rats

The comparative metabolism of (+)- and (-)-gossypol in rats was studied. After oral administration of the drugs to rats, the half-lives of (+)- and (-)-gossypol in the gastrointestinal tract were found to be 18.4 h and 13.5 h, respectively. The tissue distribution of (+)-gossypol was very similar to that of (-)-gossypol. After oral administration, high drug levels were found in the liver while moderate concentrations were present in the spleen, lungs, blood, heart and kidneys. The drug levels in the testes and fat were rather low. The excretion rates of the (+)- and (-)-gossypol were quite similar. Most of the ingested drug was excreted in the feces, while only a small fraction was eliminated in the urine. After i.v. injection of the drugs to rats, the half-lives of free (+)- and (-)-gossypol were found to be 7.80 h and 3.96 h, respectively. The clearance rates of the two optical isomers were 7.81 and 29.36 ml/h, respectively.