Characterizing the relationship between the pharmacokinetics (PK, concentration vs. time) and pharmacodynamics (PD, effect vs. time) is an important tool in the discovery and development of new drugs in the pharmaceutical industry. The purpose of this publication is to serve as a guide for drug discovery scientists toward optimal design and conduct of PK/PD studies in the research phase. This review is a result of the collaborative efforts of DMPK scientists from various Metabolism and Pharmacokinetic (MAP) departments of the global organization Novartis Institute of Biomedical Research (NIBR). We recommend that PK/PD strategies be implemented in early research phases of drug discovery projects to enable successful transition to drug development. Effective PK/PD study design, analysis, and interpretation can help scientists elucidate the relationship between PK and PD, understand the mechanism of drug action, and identify PK properties for further improvement and optimal compound design. Additionally, PK/PD modeling can help increase the translation of in vitro compound potency to the in vivo setting, reduce the number of in vivo animal studies, and improve translation of findings from preclinical species into the clinical setting. This review focuses on three important elements of successful PK/PD studies, namely partnership among key scientists involved in the study execution; parameters that influence study designs; and data analysis and interpretation. Specific examples and case studies are highlighted to help demonstrate key points for consideration. The intent is to provide a broad PK/PD foundation for colleagues in the pharmaceutical industry and serve as a tool to promote appropriate discussions on early research project teams with key scientists involved in PK/PD studies.
ABSTRACT:The aim of this study was to elucidate the metabolic pathways for dihydroartemisinin (DHA), the active metabolite of the artemisinin derivative artesunate (ARTS). Urine was collected from 17 Vietnamese adults with falciparum malaria who had received 120 mg of ARTS i.v., and metabolites were analyzed by high-performance liquid chromatography-mass spectrometry (HPLC-MS). ) but not with UGT1A1 or UGT1A6. There was no significant metabolism of DHA by cytochrome-P450 oxidation or by cytosolic sulfotransferases. We conclude that ␣-DHA-G is an important metabolite of DHA in humans and that its formation is catalyzed by UGT1A9 and UGT2B7.
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ABSTRACT:UGT1A6 and UGT1A9 have both been demonstrated to rapidly glucuronidate simple phenolic compounds. A series of simple phenols were selected and screened with both isoforms and then used as model substrates for the generation of V max and K m values. UGT1A6 showed a more restricted acceptance of phenolic substrates compared with UGT1A9. However, the affinity of UGT1A6 for these compounds exhibited higher K m values than UGT1A9, although rates of turnover were similar. Molecular surfaceweighted holistic invariant molecular descriptors were generated for each substrate and used to produce the first quantitative structure activity relationship models generated for expressed human UGTs. Models relating log of the K m value to the generated descriptors correlated well with the experimental data r 2 value of
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