We also thank the IMTech, a constituent laboratory from the Council of Scientific and Industrial Research, for facilities.
1521-009X/41/4/89705 25.00 DRUG METABOLISM AND DISPOSITION Copyright 2013 by The American Society for Pharmacology and Experimental Therapeuticshttp://dx.doi.org/10.1124/dmd.112.050054 Drug Metab Dispos 41:89705, AprilLysosomal Sequestration (Trapping) of Lipophilic Amine (Cationic Amphiphilic) Drugs in Immortalized Human Hepatocytes (Fa2N-4 Cells)Faraz Kazmi, Tiffini Hensley, Chad Pope,1 Ryan S. Funk,two Greg J. Loewen, David B. Buckley, and Andrew ParkinsonXenoTech, LLC, Lenexa, Kansas (F.K., T.H., C.P., G.J.L., D.B.B.); Department of Pharmaceutical Chemistry, University of Kansas, Lawrence, Kansas (R.S.F.); and XPD Consulting, Shawnee, Kansas (A.Rinucumab Inhibitor P.)Received November 29, 2012; accepted February 1,ABSTRACT Lipophilic (logP 1) and amphiphilic drugs (also called cationic amphiphilic drugs) with ionizable amines (pKa 6) can accumulate in lysosomes, a course of action called lysosomal trapping. This method contributes to presystemic extraction by lysosome-rich organs (such as liver and lung), which, together together with the binding of lipophilic amines to phospholipids, contributes to the large volume of distribution characteristic of many cardiovascular and central nervous technique drugs. Accumulation of lipophilic amines in lysosomes has been implicated as a cause of phospholipidosis. Additionally, elevated levels of lipophilic amines in lysosomes can cause high organ-to-blood ratios of drugs that can be mistaken for active drug transport. In the present study, we describe an in vitro fluorescence-based strategy (applying the lysosome-specific probe LysoTracker Red) to identify lysosomotropic agents in immortalized hepatocytes (Fa2N-4 cells). A diverse set of compounds with numerous physicochemical properties had been tested, which include acids, bases, and zwitterions. Also, the partitioning with the nonlysosomotropic atorvastatin (an anion) along with the lysosomotropics propranolol and imipramine (cations) have been quantified in Fa2N-4 cells in the presence or absence of a variety of lysosomotropic or nonlysosomotropic agents and inhibitors of lysosomal sequestration (NH4Cl, nigericin, and monensin).DCVC Autophagy Cellular partitioning of propranolol and imipramine was markedly reduced (by a minimum of 40 ) by NH4Cl, nigericin, or monensin.PMID:23557924 Lysosomotropic drugs also inhibited the partitioning of propranolol by at the least 50 , with imipramine partitioning impacted to a lesser degree. This study demonstrates the usefulness of immortalized hepatocytes (Fa2N-4 cells) for determining the lysosomal sequestration of lipophilic amines.Introduction Lysosomes are acidic organelles (pH four) that play a essential function in different metabolic processes, including the turnover of phospholipids, the breakdown of endogenous waste items (which includes bacteria andThis work was supported in component by the National Institutes of Well being National Institute of Common Health-related Sciences [Grant T32-GM008359] (to R.S.F.). 1 Current affiliation: Division of Pharmaceutical Sciences, University of Connecticut, Storrs, Connecticut. 2 Present affiliation: Clinical Pharmacology and Healthcare Toxicology, Children’s Mercy Hospital, Kansas City, Missouri. Portions of this work had been previously presented in the following meetings: Kazmi F, Funk R, Pope C, Czerwinski M, Yerino P, Bolliger P, Buckley D and Parkinson A (2011) A robust system to recognize compounds that undergo intracellular lysosomal sequestration. Seventeenth.
