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Updated: Apr 28, 2026
Functional Characterization of Carboxylesterases in Insecticide Resistant House Flies, Musca Domestica
Published on: August 23, 2018
Measurement of plasma protein and lipoprotein binding of pyrethroids
Pankaj K Sethi1, S Muralidhara1, James V Bruckner1
1Department of Pharmaceutical and Biomedical Sciences, College of Pharmacy, University of Georgia, Athens, GA 30602-2354, USA.
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.
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