Simultaneous Determination of Isoniazid,Rifampicin and Pyrazinamide in Pharmaceuticals and Human Urine by Cloud Point Extraction High Performance Liquid Chromatography
Isoniazid(IN) can not be sufficiently extracted by the cloud point extraction(CPE) of polylethyleneglycol(PEG) 6000,and reacts with para-chlorobenzaldehyde to form a derivative(para-chlorobenzaldehyde-isonicotiny-hydrazone,CIH).It was proven that there was linear relationship between the signal of CIH and the concentration of IN.A cloud point extraction system of polylethyleneglycol 6000(NH4)2SO4 coupled with high performance liquid chromatography was developed for the separation and the simultaneous determination of isoniazid(IN),pyrazinamide(PZ) and rifampicin(RF).Under the optimum conditions,the analytes were eluted with a gradient mode and detected with a UV-detector at 310 nm,the retention time of isoniazid,pyrazinamide and rifampicin was 14.5,34.4 and 38.1 min,respectively,the linear calibration curves in the range of 0.01-10 mg/L for isoniazid and 0.05-20 mg/L for pyrazinamide and 0.08-25 mg/L for rifampicin,respectively(r0.99).Average recoveries of three drugs ranged from 91.5% to 98.6% with relative standard deviations from 0.2% to 1.5%.The limits of detection of IN,PZ and RF was 4×10-3,2×10-2 and 3×10-2 mg/L,respectively.The CPE-HPLC-UV method had been applied to the determination of IN,PZ and RF in pharmaceuticals and in urine samples.