Selective simultaneous ultra-performance liquid chromatographic quantification of some benzodiazepines drug residues in pharmaceutical industrial wastewater

Abstract

Purpose: To investigate the sensitivity and selectivity of ultra-performance liquid chromatographic (UPLC) quantification of bromazepam (BRZ) and diazepam (DZP) in pharmaceutical industrial wastewater. Methods: Wastewater samples were collected from the effluents of a pharmaceutical industrial plant producing BRZ and DZP in tablet dosage forms. The quantification of BRZ and DZP was done after their solid-phase extraction. The resolution process was performed on WatersTM column as the stationary phase. The mobile phase was acetonitrile: methanol: 0.05 M phosphate buffer (pH 6.5), at a volume ratio of 5:2:3, with a flow rate of 0.7 mL/min. Detection was carried out at 240 nm in a concentration range of 10 - 250 ng/mL. The method was fully validated in line with ICH-Q2B regulations. Results: The UPLC method was validated for the quantification of BRZ and DZP. The relative percentage recoveries were 99.55 ± 0.48 (n = 5) and 101.34 ± 0.86 (n = 5), for BRZ and DZP, respectively, in spiked distilled water, and 99.16 ± 0.77 (n = 5) and 99.32 ± 0.56 (n = 5), in tap water, respectively. The UPLC revealed effluent content ranging from 20.68 - 44.77 mg/mL for BRZ and 22.77 - 41.83 ng/mL for DZP. These values were not significantly different from their reference standards (p > 0.05). Conclusion: A sensitive and selective UPLC-method has been developed for the reproducible determination of BRZ and DZP in industrial wastewater samples. The effective monitoring of the pharmaceutical industrial pollutant will help to conserve the environment and minimize the hazardous effects of these pollutants.