Determination of ethyl-p-hydroxybenzoate in sow pancreatic juice by reversed-phase high-performance liquid chromatography

We have developed a high-performance liquid chromatographic-UV-Vis-diode-ar ray detection (HPLC-DAD) method for the determination of ethyl-p-hydroxyben zoate, a hydrolytic degradation product of the synthetic protease inhibitor , gabexate-mesilate erhyl-p-(6-guanidinohexanoyloxy) benzoate methanesulfon ate (CM) (FOY) in sow pancreatic juice. Methyl-p-hydroxybenzoate (I) was us ed as the internal standard. The pancreatic juice was deproteinised by acet onitrile and the analytes were chromatographed on a reversed-phase C-18 LC column using the gradient elution method. The mobile phase consisted of a s olution of 0.017 M orthophosphoric acid and another solution of acetonitril e-water (80:20, v/v). The wavelength of detection was 237 nm. The limit of quantification of the method was 0.20 muM at a 9:1 Signal-to-noise ratio. T he overall intra- and inter-day accuracy (relative error, RE) ranged from 1 4.2 to 8.3% and from 13.3 to 9.8, respectively. The overall intra- and inte r-day precision (relative standard deviation, RSD) ranged from 7.6 to 2.62% and from 6.7 to 3.1%, respectively. The method proved to be sensitive, spe cific, accurate and precise and was successfully used to determine the ethy l-p-hydroxybenzoate (II) in sow pancreatic juice. (C) 2001 Elsevier Science B.V. All rights reserved.