Analysis of Ethylene Glycol and Diethylene Glycol in Glycerin, Propylene Glycol and Sorbitol Solutions (Indian Pharmacopoeia Monographs)

Significance of the Topic

Contamination of pharmaceutical excipients such as glycerin, propylene glycol and sorbitol with toxic impurities ethylene glycol (EG) and diethylene glycol (DEG) can lead to acute health hazards. Rigorous testing is essential to protect public health and ensure regulatory compliance.

Objectives and Study Overview

This application note demonstrates a GC-FID method using Shimadzu Brevis GC-2050 coupled with an AOC-30i autosampler to detect and quantify trace levels of EG and DEG in raw glycerin, propylene glycol and 70 % sorbitol solutions in compliance with Indian Pharmacopoeia monographs.

Methodology and Instrumentation

Samples were prepared per IP monographs. Glycerin and propylene glycol test solutions were dissolved in methanol at defined concentrations; sorbitol solutions used an acetone–water (96:4) solvent mixture. The compact Brevis GC-2050, featuring SH-1701 and SH-624 capillary columns, was operated in split mode with nitrogen carrier gas and FID detection. Temperature programs were adjusted to optimize separation and prevent backflash. System suitability parameters—resolution, repeatability, LOQ and LOD—were evaluated.

Key Findings and Discussion

System suitability tests yielded %RSD values below 1.5 % and resolution metrics exceeding IP requirements for all analyte pairs. LOQ was established at 7.5–10 ppm for both EG and DEG, corresponding to <0.03 % in raw materials. Analysis of raw samples showed no detectable EG or DEG in glycerin and propylene glycol, and EG in sorbitol below the pharmacopoeial limit.

Advantages and Practical Applications

• Compact design with reduced footprint and power consumption enhances lab efficiency.
• Superior reproducibility and sensitivity ensure compliance with pharmacopeial standards.
• Automated multi-data reporting with pass/fail judgments accelerates quality control.

Future Trends and Applications

Integration of advanced automation and data analytics will further streamline impurity testing. Development of even smaller, field-deployable gas chromatography systems could enable on-site screening. Expanding this approach to other toxic contaminants will strengthen pharmaceutical excipient safety.

Conclusion

The Brevis GC-2050 method offers a robust, eco-friendly and compliant solution for trace analysis of EG and DEG in key excipient materials, safeguarding product quality and public health.

Reference

• Reuters Cough syrup killed scores of children. Why no one has been held to account. Accessed June 26, 2024.
• Reuters WHO investigating links between cough syrup deaths, considers advice for parents. Accessed June 24, 2024.