Development of an LC–DAD Method for Analysis of Dexketoprofen, Tramadol, and Haloperidol. Study of the Stability of Mixtures Used for Patient-Controlled Analgesia

Abstract

Dexketoprofen (D-KTP), tramadol (TMD), and haloperidol (HLP), two analgesic agents and an adjuvant, respectively, were analysed simultaneously in 0.9% NaCl and 5% glucose by use of a new, rapid LC–DAD method. Chromatographic separation was achieved on a C18 column with 50:50 (v/v) acetonitrile–sodium dihydrogen phosphate (pH 4.10; 0.1 M) as mobile phase at a flow rate of 1 mL min−1. Ultraviolet diode-array detection was used. The absorbance of the eluate was monitored at 210 nm. The retention times of the three compounds were 2.0, 4.0, and 8.3 min for TMD, HLP, and D-KTP, respectively; the total run time was 9 min. The method was validated for linearity, accuracy, reproducibility, and limits of quantification and detection. Calibration functions were established between 100.0 and 225.0 mg L−1 for D-KTF, between 200.0 and 450.0 mg L−1 for TMD, and between 2.0 and 4.5 mg L−1 for HLP. Recoveries were >98% with precision less than 2.2% for the three drugs prepared in both 0.9% NaCl and 5% glucose. The method was successfully used to evaluate the chemical stability of this drug mixture at the usual concentration used in patient-controlled analgesia. Samples were prepared at 2.5 mg mL−1 D-KTF, 5.0 mg mL−1 TMD, and 0.05 mg mL−1 HLP in 0.9% NaCl and in 5% glucose. Stability was assumed if the loss was less than 10% of the initial concentration. Five different storage conditions were tested for 30 days and the drug mixture was stable under all these. Stability was independent of medium, 0.9% NaCl or 5% glucose. The best results were obtained for the drug mixture stored at 4 °C in darkness.