The isolation of trazodone from the biological fluids

Abstract

The aim of the work – to optimize the method for Trazodone isolation from blood and urine by liquid-liquid extraction technique. Materials and Methods. The study was carried out with model samples of human biofluids spiked with Trazodone. The antidepressant was isolated from the blood and urine by the liquid-liquid extraction technique with methylene chloride from the alkaline aqueous medium at pH 9 at the presence of ammonium sulphate as a salting-out agent. The biological impurities were previously removed by extraction with diethyl ether from the acidic medium at pH 1. The erythrocyte mass of the blood was pre-precipitated with the help of 5% trichloroacetic acid. The resulting extracts were additionally purified using TLC technique. Quantitative determination of Trazodone in the extracts was carried out with the help of UV spectrophotometry. Results and Discussion. Trazodone was detected in the biological extracts by UV spectra which coincided with standard methanol solution of the analyte and had the principal peak at wavelength of 251±2 nm. Quantitative determination of the drug in the extracts was performed with the help of calibration curve described by the equation y=(0.0230±1×10-4)×x, which showed linearity in the range of analyte concentration 2.5–50.0 μg/mL. Recovery values of the developed sample preparation methods were determined in the range of the drug concentrations of 10–50 μg/mL and 4–20 μg/mL for blood and urine respectively. Conclusions. Effective methods for Trazodone isolation from blood and urine using liquid-liquid extraction in the presence of ammonium sulphate as a saltingout agent have been developed. It has been established that liquid-liquid extraction in the presence of electrolytes provided more effective Trazodone isolation from the biological fluids than under optimized conditions without salting-out agents. The recovery of the optimized methods was 52±3% for blood and 91±3% for urine that provided sufficient extraction yield of the antidepressant for its determination within the level of the expected acute concentrations in the biological fluids. The ability of UV spectrophotometry as an analytical method for determination of Trazodone in biological fluids has been proven by a range of validation parameters. The obtained results can be used for forensic toxicological examinations in cases of acute and fatal intoxications by antidepressants.