Rifampicin is an antibiotic drug and Isoniazid is an antitubercular drug. Simple, accurate, precise, reproducible, requiring no prior separation and economical procedures for simultaneous estimation of Rifampicin and Isoniazid in tablet dosage form have been developed. Method employs formation and solving of simultaneous equation using 339 nm and 265 nm as two analytical wavelengths for both drugs in chloroform. Rifampicin and Isoniazid at their respective λmax 339.0 nm and 265 nm shows linearity in a concentration range of 5-35μg /mL and 5-25μg /mL. Recovery studies for Rifampicin 99.56 % and 100.01% for Isoniazid in case of simultaneous equation method confirming the accuracy of the proposed method. The proposed method is recommended for routine analysis since it is rapid, simple, accurate and also sensitive and specific.
