Determination of polymyxin E1 in rat plasma by high-performance liquid chromatography

A precise and accurate HPLC assay for polymyxin E-1 in rat and dog plasma has been validated. Samples and standards are extracted from plasma with a 96-well C-8 extraction disk plate. Sample extracts are derivatized with dansyl chloride, and polymyxin E-1 derivative is quantitated on a C-8 column by HPLC with fluorescence detection. The assay is linear in the range of 0.050-5.00 mug/ml for polyrnyxim E-1. The precision and accuracy of polymyxin E-1 plasma assay was well within the recommended limits set in the FDA Guidance for Bioanalytical Method Validation. Polymyxin E-1 stability in rat and dog plasma for 24 h at room temperature and through three freeze-thaw cycles was demonstrated. (C) 2003 Elsevier Science B.V. All rights reserved.