Modernizing USP Melatonin Liquid Chromatographic Analyses for Increased Throughput and Reduced Environmental Impact

Area of Science:

• Analytical Chemistry
• Pharmacology
• Environmental Science

Background:

• Concerns exist regarding melatonin supplement quality due to content inconsistencies.
• Traditional analytical methods for melatonin require modernization for efficiency and environmental sustainability.

Purpose of the Study:

• To optimize routine liquid chromatographic analyses for melatonin as per the US Pharmacopeia (USP) monograph.
• To enhance quality control testing of melatonin supplements using High Performance Liquid Chromatography (HPLC).

Main Methods:

• Optimized melatonin assay and impurities testing using a C18 column with 2.5 µm particles.
• Adjusted column length and gradient elution parameters per USP General Chapter <621> guidelines.
• Optimized mobile phase composition and flow rate to meet USP system suitability requirements.

Main Results:

• Achieved USP system suitability requirements for relative retention time, resolution, and relative standard deviation.
• Demonstrated excellent linearity, sensitivity, accuracy, and precision (repeatability).
• The optimized methods show a reduced environmental impact compared to legacy procedures.

Conclusions:

• The optimized HPLC methods offer significantly increased throughput and reduced environmental impact for melatonin analysis.
• These improved methods can be implemented on existing HPLC systems without extensive re-validation.
• The study provides a faster, more eco-friendly approach to ensuring melatonin supplement quality.