Currently,a physiologically based pharmacokinetic(PBPK)model plays a key role in pharmaceutical research,which has been widely used at each stage of drug discovery and develop?ment. In the process of drug discovery,the selection of drug candidates is finished using the PBPK model to predict the pharmacokinetic properties of the drugs. In the process of preclinical development , through a combination of in vitro and physiological data amplification coefficient,the PBPK model can be used to predict not only the overall pharmacokinetic behavior of drug candidates in humans and animals and in vitro metabolism experiments,but also drug-drug interactions(DDI). In the course of clinical development,the PBPK model can help predict the difference between reference populations (age,different disease state,and polymorphism),especially the dosage and sampling time of the children. At present,the input parameters of PBPK model are mostly the mean values of the population,making it difficult to serve individuals. It is hoped that the input parameters of the model can reflect more of the individual characters according to the individual requirement,and that the time parameters of the input accord more with the actual physiological condition. In this article ,we briefly introduced the characteristics of common PBPK software,and reviewd the principle and feature of the PBPK model,as well as its application to drug discovery,preclinical development and clinical development,DDI,and individualized medication.

Objective:To compare the cost-effectiveness of hospitalized Chinese patients undergoing nucleic acid screening strategies for hepatitis B and hepatitis C, immunological screening strategy, and no screening strategy under different willingness to pay (WTP). The results might aid to decision-making for the optimal strategy.Methods:In this study, nucleic acid screening, immunological screening and no screening were used as screening strategies, and China′s GDP in 2021 (80 976 yuan) was used as the threshold of WTP to construct a Markov model. After introducing parameters related to the diagnosis and treatment of hepatitis B and C in inpatients, a cohort population of 100 000 inpatients was simulated by TreeAge Pro 2021 software, the total cost, total health effects, incremental cost-effectiveness ratio and average cost-effectiveness ratio of different screening strategies were calculated, and cost-effectiveness analysis was conducted. Univariate and probabilistic sensitivity analysis were used to assess the impact of parameter uncertainty on the final results.Results:Compared with the non-screening strategy, the incremental total cost of the hepatitis B immunological screening strategy for cohort patients was 11 049 536 yuan, and the incremental cost-effectiveness ratio was 24 762 yuan/quality-adjusted life years (QALY), while the total incremental cost of nucleic acid screening was 19 208 059 yuan, and the incremental cost-effectiveness ratio was 29 873 yuan/QALY; the incremental cost-effectiveness ratio of nucleic acid screening and immunological screening was 45 834 yuan/QALY. Compared with the non-screening strategy, the incremental cost-effectiveness ratio of hepatitis C immunological screening strategy was 5 731 yuan/QALY, the incremental cost-effectiveness ratio of nucleic acid screening strategy was 8 722 yuan/QALY, the incremental cost-effectiveness ratio of nucleic acid screening and immunological screening was 45 591 yuan/QALY. The results of probabilistic sensitivity analysis showed that when the cost of nucleic acid testing exceeded 214.53 yuan, it was not cost-effective to perform hepatitis B nucleic acid screening under the WTP as 1 fold GDP. When the cost of nucleic acid testing exceeded 132.18 yuan, it was not cost-effective to conduct hepatitis C screening under the WTP as 1 fold GDP.Conclusions:Nucleic acid screening strategy can achieve more cost-effectiveness and is worthy of vigorous promotion. Compared with no screening, both the nucleic acid and immunological screening strategies are cost-effective, and hepatitis nucleic acid screening is the optimal strategy for hospitalized patients.