First-derivative spectrophotometric determination of pyridoxine hydrochloride in pharmaceutical preparations

We describe a rapid and selective method for the determination of pyridoxine hydrochloride in multivitamin preparations applying derivative spectrophotometry (DS). Spectral interference from formulation excipients and other drugs was canceled out at the zero-crossing wavelength at 306 nm for the oral solution, and at 308 nm for injection and capsules. Linear calibration curves were obtained within a concentration range from 2.50 to 30.00 mug/mL; correlation coefficients for the first-order derivatives values were 0.99997 (306 nm) and 0.99993 (308 nm). Recoveries from simulated analytical sample solutions ranged from 97.2 to 100.3%, and coefficients of variation ranged from 0.28 to 0.76%. DS data were in agreement with results obtained by applying the USP method. The technique is simple, fast, and accurate and does not require separation steps.