In this review,we introduce the method used in the sample preparing and determination of free drug monitoring.

AIM To establish a simple and practical method for the estimation of the inter-patient variability of cytochrome P450(CYP3A)enzyme activity and to predict drug concentration and parmacokinetics of etoposide with the variability of CYP3A in chidren patients with leukemia.

Objective: To establish a HPLC method for the determination of the drug concentration in bile after the injection of lomefloxacine.

It was found that SM2 was absorbed quickly and distributed widely, the concentrations in the tissues of heart, liver, lung, kidney and small intestine were all higher,facially, the drug concentration in the tissue of small intestine was highest.

Association between valproic acid plasma concentration and CYP2C19 gene ploymorphism;

Centrifugation of minicolumn to remove free drugs from liposomes to determine the encapsulation efficiency by calculation the drug-to-phospholipid ratio;