Simultaneous determination of cefmetazole and cefaclor in urine from pediatric patients with urinary tract infections using a newly developed high-performance liquid chromatography assay method.

Background: A simple and rapid assay method is urgently required in clinical settings to monitor the efficacy and safety of antibiotics in pediatric patients with urinary tract infection (UTI).

Aims: To develop a cost-effective high-performance liquid chromatography-ultraviolet (HPLC-UV) method to simultaneously determine cefaclor and cefmetazole concentrations in the urine of pediatric patients with UTI.

Materials and methods: Calibration curves were used to validate the linear ranges of cefaclor (31.25 - 500 µg/mL) and cef-metazole (62.5 - 1,000 µg/mL).

Results: The developed method showed satisfactory precision: intra-day coefficients of variations (CV) 1.1 - 7.6% and inter-day CV of 3.7 - 13.8% for cefaclor, and intra-day CV of 0.5 - 5.9% and inter-day CV of 4.5 - 13.2% for cefmetazole. The validity of the method was confirmed using urine bag samples from infants with UTI. The urinary concentrations of cefaclor and cefmetazole in infants with UTI were 313.5 μg/mL and 1,572.5 μg/mL, respectively.

Conclusion: We developed and validated an HPLC-UV method for the simultaneous measurement of cefaclor and cefmetazole in pediatric patients with UTI. The assay is rapid, cost-effective, and suitable for therapeutic drug monitoring.