Development and validation of a rapid high-performance liquid chromatography method for the quantification of exenatide

The objective was to develop a simple HPLC method to quantify exenatide—a 39 amino acid residue incretin mimetic used in diabetes therapy. To date, only non‐validated, sometimes incomplete, gradient methods have been reported in the literature. Isocratic separation was achieved using a C₄ column and a mixed solvent system, A–B–C (48:45:7, v/v/v; pH* 5.2), where A represents KH₂PO₄ (pH 4.5; 0.1 m ) and MeCN (60:40, v/v), B corresponds to NaClO₄·H₂O (pH 6.0; 0.2 m ) and MeCN (60:40, v/v), and C is water. Exenatide eluted at 3.64 min and the total run time was 6 min. The method was specific and the response was accurate, precise and linear from 0.75 to 25 µg/mL. It was used to quantify exenatide transport across intact and laser‐porated porcine skin in vitro as a function of laser fluence [0 (i.e. intact skin), 9 and 15 J/cm², respectively]. Although no permeation was observed using intact skin, cumulative exenatide permeation after 8 h through laser porated skin was 9.6 ± 6.5 and 12.4 ± 6.4 µg/cm² at fluences of 9 and 15 J/cm², respectively. This is the first validated isocratic method for exenatide quantification and it may be of use in quality control analysis and with other biological matrices. Copyright © 2010 John Wiley & Sons, Ltd.