title: A Fragment-Based Approach for the Computational Prediction of the Nonspecific Binding of Drugs to Hepatic Microsomes.
abstract: Correction for the nonspecific binding (NSB) of drugs to liver microsomes is essential for the accurate measurement of the kinetic parameters Kmand Ki, and hence in vitro-in vivo extrapolation to predict hepatic clearance and drug-drug interaction potential. Although a number of computational approaches for the estimation of drug microsomal NSB have been published, they generally rely on compound lipophilicity and charge state at the expense of other physicochemical and chemical properties. In this work, we report the development of a fragment-based hologram quantitative structure activity relationship (HQSAR) approach for the prediction of NSB using a database of 132 compounds. The model has excellent predictivity, with a noncross-validated r2of 0.966 and cross-validated r2of 0.680, with a predictive r2of 0.748 for an external test set comprising 34 drugs. The HQSAR method reliably predicted the fraction unbound in incubations of 95% of the training and test set drugs, excluding compounds with a steroid or morphinan 4,5-epoxide nucleus. Using the same data set of compounds, performance of the HQSAR method was superior to a model based on logP/D as the sole descriptor (predictive r2for the test set compounds, 0.534). Thus, the HQSAR method provides an alternative approach to laboratory-based procedures for the prediction of the NSB of drugs to liver microsomes, irrespective of the drug charge state (acid, base, or neutral).
authors.affiliation: Department of Clinical Pharmacology (P.C.N., J.O.M.) and Flinders Centre for Innovation in Cancer (P.C.N., R.A.M., J.O.M.), School of Medicine, Flinders University, Adelaide, Australia pramod.nair@flinders.edu.au.
authors.forename: Pramod C
authors.initials: PC
authors.lastname: Nair
authors.affiliation: Department of Clinical Pharmacology (P.C.N., J.O.M.) and Flinders Centre for Innovation in Cancer (P.C.N., R.A.M., J.O.M.), School of Medicine, Flinders University, Adelaide, Australia.
authors.forename: Ross A
authors.initials: RA
authors.lastname: McKinnon
authors.affiliation: Department of Clinical Pharmacology (P.C.N., J.O.M.) and Flinders Centre for Innovation in Cancer (P.C.N., R.A.M., J.O.M.), School of Medicine, Flinders University, Adelaide, Australia.
authors.forename: John O
authors.initials: JO
authors.lastname: Miners
mesh_terms: D006801:Humans; D007700:Kinetics; D008099:Liver / Q000378:metabolism*; D008862:Microsomes, Liver / Q000378:metabolism*; D008954:Models, Biological; D004364:Pharmaceutical Preparations / Q000378:metabolism*; D021281:Quantitative Structure-Activity Relationship
chemical_list: D004364:Pharmaceutical Preparations