Validated Method for Determination of α‐Lipoic Acid in Dietary Supplement Tablets by Reversed Phase Liquid Chromatography

Abstract

A rapid high performance liquid chromatographic method was developed and validated for the determination of α‐lipoic acid in pharmaceutical dosage forms. The analysis was performed using a reversed phase Supelcosil LC‐18 (150 × 4 mm, 3 µm) column. The mobile phase consisted of acetonitrile:0.05 M potassium mono‐phosphate, pH 2.5 (45:55 v/v) at a flow rate of 0.8 mL/min. The UV‐detector was set at 332 nm. The developed method showed a good linear relationship in the concentration range from 10–500 µg/mL with a correlation coefficient from 0.9999. The limit of detection and limit of quantification were 4.4 and 16.8 µg/mL, respectively. These values are high due to the low absorption coefficient of pure lipoic acid (ϵ = 150) at 332 nm. Statistical analysis proves that the method is reproducible.

Keywords:

• HPLC
• α‐Lipoic acid
• Dietary supplement
• Pharmaceutical analysis
• High performance liquid chromatography

Acknowledgment

The authors (H.Y. Aboul‐Enein and H.L.M.N.P. Hoenen) would like to thank the King Faisal Specialist Hospital and Research Centre administration for their support for the Pharmaceutical Analysis Laboratory Research Program.