Native Fluorescence Determination of Pyridoxine Hydrochloride (Vitamin B₆) in Pharmaceutical Preparations After Sorption on Sephadex SP C‐25

Abstract

A simple, batch mode, solid phase spectrofluorimetric procedure has been developed for the determination of pyridoxine hydrochloride (PY) (vitamin B₆). The method is based on the measurement of the native fluorescence of the analyte at 395 nm (λ_exc = 295 nm) sorbed on Sephadex SP C‐25 beads. The cation‐exchange gel, previously equilibrated with the sample solution, is packed in a 1‐mm quartz cell in which the measurements are performed (diffuse transmitted fluorescence).

The method responds linearly in the measuring range of 50–500, 10–100 and 5–40 μg·l^− 1 with detection limits of 9.5, 2.3 and 0.60 μg·l^− 1 for 10, 25 and 50 ml of sample volume, respectively.

The relative standard deviation (n = 10) for the determination of 100 (10 ml), 60 (25 ml) and 30 μg·l^− 1 (25 ml) of PY is 1.3%, 2.2% and 3.7%, respectively. The method, which shows increasing sensitivity as the sample volume increases, was satisfactorily applied to the determination of vitamin B₆ in pharmaceutical preparations using the procedure for 10 ml of sample.

Keywords:

• Pyridoxine hydrochloride
• Solid phase spectrofluorimetry
• Drug formulations

Acknowledgments

The authors are grateful to Dirección General de Investigación of the Ministerio de Ciencia y Tecnología (Project no. PB98‐0301) for financial support.