Simultaneous determination of pyridoxine hydrochloride and doxylamine succinate from tablets by ion pair reversed-phase high-performance liquid chromatography (RP-HPLC).

A new, simple, precise, and rapid ion pair reversed-phase high-performance liquid chromatography (RP-HPLC) method has been developed for the simultaneous determination of pyridoxine hydrochloride (PYR) and doxylamine succinate (DOX) in tablets. The stationary phase was a Microbondapak C18 column (10 mu, 300 mm x 3.9 mm i.d.). The mobile phase was water:methanol (60:40) containing 10 mM heptanesulfonic acid and 0.25% triethylamine and adjusted to pH 2.2 with orthophosphoric acid. Detection was carried out at 263 nm using an ultraviolet (UV) detector. The flow rate was 1.0 ml/min, and retention times were 3.65 min and 7.32 min for PYR and DOX, respectively. The linearity was obtained in the concentration range 0.5-500 micrograms/ml for PYR and DOX. Mean percentage recoveries were 100.20% and 101.20% for PYR and DOX, respectively.