Monitoring of amoxicilline and ceftazidime in the microdialysate of diabetic foot and serum by capillary electrophoresis with contactless conductivity detection.

Abstract

Determination of the broad-spectrum antibiotics amoxicilline (AMX) and ceftazidime (CTZ) in blood serum and microdialysates of the subcutaneous tissue of the lower limbs is performed using CE withcontactless conductivity detection (C4 D). Baseline separation of AMX is achieved in 0.5 M acetic acid as the background electrolyte and separation of CTZ in3.2 M acetic acid with addition of 13% v/v methanol. The CE-C4 D determination is performed in a 25µm capillary with suppression of the EOF using INST-coating on an effective length of 18cm and the attained migration time is 4.2min for AMX and 4.4min for CTZ. The analysis was performed using 20µl of serum and 15µl of microdialysate, treated by the addition of acetonitrile in a ratio of 1/3 v/v and the sample is injected into the capillary using the large volume sample stacking technique. The LOQ attained in the microdialysate is 148ng/ml for AMX and 339ng/ml for CTZ, and in serum 143ng/ml for AMX and 318ng/ml for CTZ. The CE-C4 D method is employed for monitoring the passage of AMX and CTZ from the blood circulatory system into the subcutaneous tissue at the sites of diabetic ulceration in patients suffering from diabetic foot syndrome and also for measuring the pharmacokinetics following intravenous application of bolus antibiotic doses.