Rapid and sensitive estimation of isoniazid, pyrazinamide and rifampicin in combined dosage form by reversed-phase liquid chromatography

Abstract A rapid and sensitive method of estimation for isoniazid, pyrazinamide and rifampicin from pharmaceutical dosage was developed. The mobile phase consisting of 80:20, methanol-tetrabutyl ammonium hydroxide (0.005N) pH 3.0 adjusted with phosphoric acid was used with an ODS -CN bonded phase column. The separation of the above drugs was accomplished within 10 min at a flow rate of 1.5 ml/min. For accurate quantitation clofazimine was used as an internal standard with UV detector set at 265 nm. No interference from a variety of excipients present in the dosage forms was observed.