Determination of isoniazid and pyridoxine in plasma sample of tuberculosis patients by micellar liquid chromatography

•We have determined ioniazid and pyridoxine in plasma by micellar liquid chromatography.•Sample treatment was expedited to a dilution and direct injection.•Method was validated by the guidelines of FDA 2018.•It was eco-friendly, rapid, economic and with high sample throughput.•It was applied to stability studies and incurred samples. It is no doubt Isoniazid is a powerful tuberculosis drug, but it might give rise to Vitamin B6 (Pyridoxine) deficiency. In this case, a usual treatment is the combined administration of Isoniazid and Pyridoxine. An easy-to-conduct procedure based on Micellar Liquid Chromatography has been developed to quantify Isoniazid and Pyridoxine in plasma from Tuberculosis patients. The sample was diluted in mobile phase, filtered and directly injected, thus avoiding extraction or purification steps. Both drugs were adequately resolved from the matrix and endogenous compounds using a mobile phase made up of 0.15 M sodium dodecyl sulfate – 8%(v/v) 1-butanol – 0.01 M phosphate buffer at pH 3, running at 1 mL/min through a C18 column at 25 °C, in less than 8 min. Detection was carried out by UV-Absorbance at 265 nm. This innovative analytical method was validated following the Food and Drug Administration Bioanalytical Method Validation Guidance for Industry (2018) with satisfactory results. The response of the drugs was linear in the range 0.1 to 15 mg/L, with r2 > 0.9990 for both compounds. Trueness and precision were 89.2–102.3% and