First-derivative spectrophotometric determination of pyridoxine hydrochloride in pharmaceutical preparations

We describe a rapid and selective method for the determination of pyridoxin e hydrochloride in multivitamin preparations applying derivative spectropho tometry (DS). Spectral interference from formulation excipients and other d rugs was canceled out at the zero-crossing wavelength at 306 nm for the ora l solution, and at 308 nm for injection and capsules. Linear calibration cu rves were obtained within a concentration range from 2.50 to 30.00 mug/mL; correlation coefficients for the first-order derivatives values were 0.9999 7 (306 nm) and 0.99993 (308 nm). Recoveries from simulated analytical sampl e solutions ranged from 97.2 to 100.3%, and coefficients of variation range d from 0.28 to 0.76%. DS data were in agreement with results obtained by ap plying the USP method. The technique is simple, fast, and accurate and does not require separation steps.