Pankaj K Sethi1, S Muralidhara2, James V Bruckner3, Catherine A White4. 1. Department of Pharmaceutical and Biomedical Sciences, College of Pharmacy, University of Georgia, Athens, GA 30602-2354, USA. Electronic address: pankaj.uga@gmail.com. 2. Department of Pharmaceutical and Biomedical Sciences, College of Pharmacy, University of Georgia, Athens, GA 30602-2354, USA. Electronic address: smuralidhara@rx.uga.edu. 3. Department of Pharmaceutical and Biomedical Sciences, College of Pharmacy, University of Georgia, Athens, GA 30602-2354, USA. Electronic address: bruckner@rx.uga.edu. 4. Department of Pharmaceutical and Biomedical Sciences, College of Pharmacy, University of Georgia, Athens, GA 30602-2354, USA. Electronic address: cwhite@rx.uga.edu.
Abstract
INTRODUCTION: A simple, reliable procedure was developed to measure binding of pyrethroid insecticides to total proteins and lipoproteins of rat and human plasma. METHODS: The extent of binding of (14)C-labeled deltamethrin (DLM), cis-permethrin (CIS) and trans-permethrin (TRANS) was quantified by a 3-step organic solvent extraction technique. Rat and human plasma samples, containing NaF to inhibit esterases, were spiked with a range of concentrations of each radiolabeled pyrethroid. Protein binding reached equilibrium within ~1h of incubation at 37°C. The samples were extracted in turn with: isooctane to collect the unbound fraction; 2-octanol to extract the lipoprotein-bound fraction; and acetonitrile to obtain the protein-bound fraction. RESULTS: Absolute recoveries of DLM, CIS and TRANS ranged from 86 to 95%. Adherence of these very lipophilic chemicals to glass and plastic was minimized by using silanized glass vials and LoBind® plastic pipettes. The method's ability to distinguish lipoprotein from protein binding was confirmed by experiments with diazepam and cyclosporine, drugs that bind selectively to albumin and lipoproteins, respectively. DISCUSSION: This procedure was effectively utilized for studies of the species-dependence of plasma protein and lipoprotein binding of three pyrethroids for inclusion in physiologically-based pharmacokinetic models of pyrethroids for use in health risk assessments of the insecticides in children and adults.
INTRODUCTION: A simple, reliable procedure was developed to measure binding of pyrethroid insecticides to total proteins and lipoproteins of rat and human plasma. METHODS: The extent of binding of (14)C-labeled deltamethrin (DLM), cis-permethrin (CIS) and trans-permethrin (TRANS) was quantified by a 3-step organic solvent extraction technique. Rat and human plasma samples, containing NaF to inhibit esterases, were spiked with a range of concentrations of each radiolabeled pyrethroid. Protein binding reached equilibrium within ~1h of incubation at 37°C. The samples were extracted in turn with: isooctane to collect the unbound fraction; 2-octanol to extract the lipoprotein-bound fraction; and acetonitrile to obtain the protein-bound fraction. RESULTS: Absolute recoveries of DLM, CIS and TRANS ranged from 86 to 95%. Adherence of these very lipophilic chemicals to glass and plastic was minimized by using silanized glass vials and LoBind® plastic pipettes. The method's ability to distinguish lipoprotein from protein binding was confirmed by experiments with diazepam and cyclosporine, drugs that bind selectively to albumin and lipoproteins, respectively. DISCUSSION: This procedure was effectively utilized for studies of the species-dependence of plasma protein and lipoprotein binding of three pyrethroids for inclusion in physiologically-based pharmacokinetic models of pyrethroids for use in health risk assessments of the insecticides in children and adults.
Authors: Jill K Morris; Brian D Piccolo; Kartik Shankar; John P Thyfault; Sean H Adams Journal: Am J Physiol Endocrinol Metab Date: 2017-12-26 Impact factor: 4.310
Authors: Pankaj K Sethi; Catherine A White; Brian S Cummings; Ronald N Hines; Srinivasa Muralidhara; James V Bruckner Journal: Pediatr Res Date: 2015-11-16 Impact factor: 3.756
Authors: Pankajini Mallick; Gina Song; Alina Y Efremenko; Salil N Pendse; Moire R Creek; Thomas G Osimitz; Ronald N Hines; Paul Hinderliter; Harvey J Clewell; Brian G Lake; Miyoung Yoon; Marjory Moreau Journal: Toxicol Sci Date: 2020-08-01 Impact factor: 4.849