A bio-analytically validated HPLC-UV method for simultaneous determination of doripenem and ertapenem in pharmaceutical dosage forms and human plasma: a dual carbapenem regimen for treatment of drug-resistant strain of Klebsiella pneumoniae

Abstract

The emergence of strains resistant to certain antibiotics is turning into an important issue worldwide that threatens global health with the increasing incidence of carbapenemase-producing Klebsiella pneumoniae (KPC). Thus, successful doripenem–ertapenem (DOR–ERTA) combination is highly recommended in treatment of bacteremic ventilator-associated pneumonia due to Klebsiella pneumoniae. Hence, a fast and highly-sensitive HPLC-UV method was developed for the estimation of the cited drugs simultaneously in their pure form, pharmaceutical dosage forms and in simulated synthetic mixtures. The DOR–ERTA mixture was successfully separated within 6 min on a reversed-phase ODS column using an isocratic elution; a mobile phase mixture consists of 0.05 M phosphate buffer (pH 3.0 adjusted by 85% ortho-phosphoric acid) : acetonitrile : methanol (86 : 12 : 2; % v/v/v). The proposed method was optimized and validated according to ICH guidelines, where the calibration graph was constructed from 0.04 to 50 μg mL⁻¹ and from 0.05 to 50 μg mL⁻¹ with low detection limits reached 1.7 and 1.4 ng mL⁻¹ for DOR and ERTA respectively. The proposed method showed higher sensitivity than several previous methods, which allowed an effective estimation of the DOR and ERTA in human plasma after a simple extraction method with high recovery results ranged from 96.30% ± 1.55 to 97.90% ± 1.45 and without any interference from plasma components.