Exploration of a high-performance liquid chromatography method for antibiotic drug monitoring in melioidosis patients and establishment of its sampling procedure

Abstract

Purpose: To establish a high-performance liquid chromatography (HPLC) method that simultaneously monitors the concentrations of sulfamethoxazole (SMZ) and trimethoprim (TMP) in the plasma of patients with melioidosis during the intensive or eradication phase. Method: The study established and verified the feasibility of HPLC method using aminopyrine as an internal standardand trichloroacetic acid as precipitant to dilute the supernatant after plasma sample treatment and chromatographic separation by Acutfex YS-C8 column (4.6 × 250 mm, 5 µm) gradient elution. The mobile phase A consisted of 1000 mL of ultrapure water plus 2 mL of triethylamine with the pH adjusted to 6.0 using glacial acetic acid, while the mobile phase B was acetonitrile. The system operated using gradient elution at a flow rate of 1.0 mL·min-1and a wavelength of 240 nm. The established method was then used to measure the plasma concentrations of SMZ and TMP in 11 melioidosis patients from the Hainan region in China. Results: SMZ and TMP showed good linearity between concentrations of 0.6–190 μg·mL−1 and 0.1–25 μg·mL−1, respectively (r values 0.9997 and 1, respectively), with a recovery rate of (102.33 ± 1.42)%-(107.12 ± 1.41)% for SMZ and (93.85 ± 3.61)%-(105.67 ± 0.42)% for TMP. Both SMZ and TMP exhibited precision and stability, with relative standard deviations below 15 %. The peak concentration range was 8.77–102.94 μg·mL−1 for SMZ and 1.89–11.27 μg·mL−1 for TMP. Conclusion: The analyses used in this study verified the HPLC method had good linearity, accuracy, and precision and can therefore be used to monitor the plasma concentrations of combined TMP/SMZ therapy in melioidosis patients.

Keywords

• Sulfamethoxazole
• Trimethoprim
• High-performance liquid chromatography
• Therapeutic drug monitoring
• Melioidosis