A simple liquid-chromatographic method for measuring vitamin B6 compounds in plasma

Area of Science:

• Biochemistry
• Analytical Chemistry
• Human Physiology

Background:

• Vitamin B6 is essential for numerous metabolic processes.
• Accurate measurement of vitamin B6 forms in plasma is crucial for clinical and research applications.
• Existing methods for vitamin B6 analysis can be complex or lack comprehensive detection.

Purpose of the Study:

• To develop and validate a simple, high-performance liquid chromatographic (HPLC) method for quantifying all known forms of vitamin B6 in human plasma.
• To investigate the plasma levels and elimination kinetics of vitamin B6 forms.
• To explore potential new pathways in vitamin B6 metabolism.

Main Methods:

• Development of a high-performance liquid chromatographic (HPLC) method.
• Analysis of plasma samples from individuals supplemented with pyridoxine hydrochloride.
• Validation of the HPLC method using analytical recovery and precision (CVs).
• Comparison of HPLC results with enzymatic and routine urine assays for specific vitamin B6 metabolites.

Main Results:

• The developed HPLC method demonstrated good analytical recovery (85-98%) and precision (CVs of 4% within-run, 7% between-run).
• Major vitamin B6 forms in unsupplemented plasma were pyridoxal phosphate and 4-pyridoxic acid.
• Pyridoxine elimination from plasma was rapid in both normal and hyperoxaluric individuals (t1/2 of 45 and 40 min, respectively).
• Evidence for two additional vitamin B6 forms was observed.

Conclusions:

• The developed HPLC method is a reliable and efficient tool for measuring multiple vitamin B6 forms in plasma.
• Pyridoxine exhibits rapid plasma clearance, indicating efficient metabolic processing.
• The findings suggest the potential existence of a novel metabolic pathway for vitamin B6.