Time-dependent changes in concentration of two clinically used acetylcholinesterase reactivators (HI-6 and Obidoxime) in rat plasma determined by hplc techniques after in vivo administration

Abstract

A simple and reliable HPLC method for determination of rat plasma levels of clinically used acetylcholinesterase (AChE) reactivators (HI-6 and obidoxime) is presented in our study. Separation was carried out by HPLC using an octadecyl silica stationary phase and a mobile phase consisting of 24% acetonitrile and containing 5 mM sodium octanesulfonate and 5 mM tetramethylammonium chloride (pH 2.3). Following intramuscular administration of equimolar doses of both oximes (22.23 mg/kg), the maximum of HI-6 concentration in rat plasma was reached in about 20 min giving 15.26 ± 1.71 μg/mL. The distribution of obidoxime was fast; the single maximum 23.62 ± 3.563 μg/mL was recorded at about 10 min. HPLC with UV detection presented in our study is a general method which could be applied for quick measurements of bisquaternary AChE reactivators in rat plasma. 2010 © The Japan Society for Analytical Chemistry.