Graduate Pharmacy Aptitude Test (GPAT) 2008 Solved Paper

In cross-over bioavailability studies, in which the subjects must be rested for sufficient time betweeneach drug administration to ensure that 'washout' is complete. Practically, wash-out is deemed complete, when
(P) 95% is wash out
(Q) 100% is wash out
(R) 5 biologica half-lives have elapsed
(S) 2 biological half-lives have elapsed