Validation of Isoniazid for Therapeutic Drug Monitoring in Human Plasma by High-Performance Liquid Chromatography

Isoniazid is one of anti-tuberculosis agent which can cause hepatotoxicity. However, not all of the TB patients and health providers can recognize early symptoms of antituberculosis-induced hepatotoxicity. Thus, the Therapeutic Drug Monitoring needs to be performed to monitor the hepatotoxicity symptoms. The aim of this study is to establish the validity of the Isoniazid assay method using High-Performance Liquid Chromatography from human plasma. We recruited 6 healthy subjects for this validation study. The validation was performed using Shimadzu HPLC system with a model AT LC20 LC 10AT pump, detector SPD 20A and LC solution software. We used C18 column shim- pack VP-ODS (250 mm x 4.6 mm, id 5 mu m) as well as other tools such as centrifuges, vortex, appliance glass (Pyrex IWAKI) and other supporting tools. Chemicals and solvents was used from Merck Germany. Isoniazid standard compounds were obtained from SIGMA. Our study has been approved by National Ethics Committee of Health Research. Our study shows that the method applied in HPLC has the good linearity (r = 0.998) with coefficient of variance (CV) of system appropriateness test is 0.61% and the equation of linearity was y=8756.87x+27724.82. The value of Limit of Detection (LoD) and Limit of Quantification (LOQ) were 1.517 mu g/ml and 4.597 mu g/ml, respectively. The precision on the concentration of 0,5; 5.0; 15.0 ug/ml are 5.24%, 0.79%, 2.83%, respectively for intraday precision and 4.86%; 2.18%; 2.01%, respectively for interday precision. The recoveries on the particular concentrations are 100.79%; 108.91%; 92.19%, respectively for intraday recovery and 101.73%; 99.63%; 82.75%, respectively for interday recovery. This validation method is a good alternative for the application of TDM in monitoring the treatment of TB patients' clinical practice