Simultaneous HPTLC determination of rifampicin and isoniazid in rat plasma

A method enabling the precise and quick simultaneous assessment of rifampicin and isoniazid in rat plasma by HPTLC has been presented. Extracted samples of rifampicin and isoniazid in organic solvents were separated on a plate coated with silica gel 60 F₂₅₄, chromatograms were de-veloped using a mixture of chloroform:methanol and quantification was carried out by the use of densitometer absorbance mode at 475 nm and 280 nm respectively. Under the operating conditions, the lower limit of detection was found to be 0.3 μg/spot for rifampicin and 0.1 μg/spot for isoniazid. The method has a linearity range of 10 to 80 μg/ml for both the drugs and recovery was found to be 97.5% for both rifampicin and isoniazid. The pharmacokinetic parameters obtained after intravenous bolus injection at a dose of 10 mg/kg has also been presented.