Editorial [Hot Topic: Multi-Component Drug ADME/T and Metabolic Interactions (Guest Editor: Ping Li)]

With the ever-increasing acceptance of combination therapy and the prevalence of chronic diseases in the world, the development of multi-component drug therapies including the use of herbs has become an emerging trend. Herbal medicines (HMs), generally prepared with a specific combination of different herbs, are becoming increasingly popular as a multi-component drug therapy. In addition, drug combination, as another multi-component therapeutics, also can be used to treat complex disease. Recently, clinical results demonstrated that multi-component therapeutics had achieved numerous successes in treating complex diseases. However, the use of multi-component drug may mimic, increase or reduce the effects of either component in drug, resulting in clinically important metabolic drug interactions. Metabolic drug interactions are as a result of altered absorption, distribution, metabolism, excretion and toxicity (ADME/T) of components. So, the study on multi-component drug ADME/T and metabolic interactions plays a major role in current drug metabolism study. It will be the aim of this special issue on Multi-component Drug ADME/T and Metabolic Interactions to illustrate the recent advances and to highlight new trends in ADME/T and metabolic interactions of multi-component drugs. It is hoped that the scientists involved in drug metabolism and the related research fields will find the selection of these reviews beneficial and informative. In the metabolism studies of multi-component drug, one requirement that is common for many stages is the need for bioanalytical methodologies or strategies. The review by G.Z. Xin et al., from State Key Laboratory of Natural Medicines, China Pharmaceutical University, illustrates the new improvement in strategies for integral metabolism profile of multiple compounds in HMs: pharmacokinetics, metabolites characterization, and metabolic interactions. HMs have played an important role in human history for preventing and treating diseases. Ginseng is an HM used worldwide. Recently, the metabolism and pharmacokinetic studies of ginseng have become an important issue.The article by C.S. Yuan et al, from the Tang Center for Herbal Medicine Research, University of Chicago, reviews the known metabolism and pharmacokinetic data on ginseng. While the use of herbal products in many cases causes adverse effects, to date, safety issues of herbal products have not been adequately addressed. It is rarely determined whether the non-purported bioactive constituents in the herbs and the metabolites of the bioactive components can lead to adverse effects. In the third review, written by G. Lin, from School of Biomedical Sciences, the Chinese University of Hong Kong, they discuss, using pyrrolizidine alkaloids as an example, the hepatotoxicity and tumorigenicity induced by metabolic activation of herbal components and by herb-herb and herb-drug interactions with other herbal ingredients and synthetic drugs. The combined use of herbs and drugs has increased the possibility of pharmacokinetic and pharmacodynamic interactions. The paper by C.X. Liu et al., from the State Key Laboratory of Drug Delivery Technology and Pharmacokinetics, Tianjin Institute of Pharmaceutical Research, highlights recent knowledge to discuss herb-drug interactions involving metabolizing enzymes and drug transporters. Translational research is an emerging discipline that aims to fill the gap through the whole pipeline from bench to bedside. This review by G.J. Wang, from Key Laboratory of Drug Metabolism and Pharmacokinetics, China Pharmaceutical University, highlights the importance and urgency of incorporating translational research into the study of pharmacokinetic herb drug interactions (PHDI), based on an intensive discussion on the controversial and inconsistent reports from preclinical to clinical, in vitro to in vivo, and across different studies concerning PHDI......