Coupling microdialysis with flow-injection chemiluminescence detection for a protein–drug interaction study

Abstract: The interaction of metronidazole (MTZ) and human serum albumin (HSA) was studied using the coupling system of on-line microdialysis sampling with flow-injection chemiluminescence detection (FI-MD-CL). The interested drug and HSA were mixed in different molar ratios in 0.067molL−1 phosphate buffer (pH 7.4) and incubated at 37°C in a water-bath. Then the microdialysis probe was put into the MTZ–HSA mixed solution and sampled at a perfusion rate of 5μLmin−1. The microdialysates was determined using flow-injection chemiluminescence. In vitro recovery (R) of MTZ under experimental conditions was approximately 25.2% with a R.S.D. of about 3.2%. The values estimated for the binding constant (K) and the number of the binding sites (n) were found to be 1.50×103 Lmol−1 and 1.89, respectively. The values of nK obtained using Scatchard analysis and Klotz plot were found to be quite similar. The method provided a reliable and simple technique for the study of drug–protein interaction. [Copyright &y& Elsevier]