Development and validation of a UHPLC‐UV method for the determination of a prostate secretory protein 94‐derived synthetic peptide (PCK3145) in human plasma and assessment of its stability in human plasma

PCK3145 is a synthetic peptide, derived from the Prostate Secreted Protein 94 (PSP94), with promising in vitro and animal in vivo results in prostate cancer. The aim of the present study was to develop and validate a fast and robust ultra‐high‐performance liquid chromatography with ultraviolet detection for the determination of PCK3145 in human plasma which would be suitable for the assessment of PCK3145 stability to proteolytic degradation. Following protein precipitation, chromatographic separation was carried out on an Aeris Peptide C₁₈ column with mobile phase consisting of acetonitrile–water at a flow‐rate of 0.50 mL/min. The calibration curve was linear over the range 0.50–20.00 μg/mL. Intra‐ and inter‐day percentage relative standard deviation and relative error were ≤10%. The limit of detection and the lower limit of quantification were 0.15 and 0.50 μg/mL, respectively. Recovery of PCK3145 from human plasma was ≥96%. The peptide presented high stability in whole blood and in human plasma (>98% intact peptide after 24 h incubation at 37°C in human plasma), which represents a distinctive advantage in the therapeutic use of the compound. This is the first validated UHPLC method for the determination of PCK3145 reported, and it was successfully applied in the study of the proteolytic stability of PCK3145 in human plasma ex vivo. Copyright © 2016 John Wiley & Sons, Ltd.