A Stability Indicating Method for the Determination of the Antioxidant Sodium Bisulfite in Pharmaceutical Formulation by RP-HPLC Technique

A stability-indicating reversed-phase high-performance liquid chromatographic (RP-HPLC) method was developed for the determination of sodium bisulfate (SB), an antioxidant, in injectable dosage form. The chromatographic separation was achieved on a Zorbax CN (250 mm × 4.6 mm, 5 μm) column, with a mobile phase consisting of a buffer mixture of 0.03 M tetrabutylammonium hydrogen sulfate, 0.01 M potassium dihydrogen orthophosphate, and acetonitrile at a ratio of 70:30 (v/v) and a flow rate of 0.7 mL/min. The eluted compound was monitored at a wavelength of 215 nm using a UV detector. The method described herein separated sodium bisulfite from all other formulation components within a run time of 10 min. The method also generated linear results over an SB concentration range of 10 to 990 μg/mL, and the limit of quantification was found to be 10 μg/mL. The stability indicating capability of the method was established by performing forced degradation experiments. The RP-HPLC method that was developed was validated according to the International Conference on Harmonization (ICH) guidelines. This method was successfully applied in the quantitative determination of SB in a stability study of Amikacin sulfate injection. The procedure described herein is simple, selective, and reliable for routine quality control analysis as well as stability testing.