A drug having 40% absorption and hepatic extraction ratio of 0.6. What is the bioavailability of that drug?

Ans. is 'a' i.e., 16% Absoion of drug is 40% i. e. if 100 mg of drug is taken 40 mg will be absorbed. Hepatic extraction ratio is 0.6 i.e. out of the absorbed dose 60% will be removed by liver; so from the absorbed 40 mg 60% removed i. e. 24 mg removed. Thus finally the remaining 16 mg of the total dose taken reaches the systemic circulation. So bioavailability is 16% as 16mg of the total 100 mg finally reached the systemic circulation