Identification and isolation of chlorhexidine digluconate impurities

Area of Science:

• Analytical Chemistry
• Organic Chemistry
• Pharmaceutical Science

Background:

• Chlorhexidine digluconate (CHG) is a widely used antiseptic.
• Understanding CHG degradation is crucial for product stability and efficacy.
• Impurities can arise from synthesis and degradation, impacting product quality.

Purpose of the Study:

• To identify and characterize impurities in stressed chlorhexidine digluconate (CHG) solutions.
• To elucidate the degradation mechanisms of CHG under various stress conditions.
• To synthesize impurity standards for accurate identification and quantification.

Main Methods:

• High-Performance Liquid Chromatography-Mass Spectrometry (HPLC-MS) for tentative identification.
• Synthesis of impurity standards.
• Flash chromatography for impurity isolation.
• Comparison of HPLC-UV and Nuclear Magnetic Resonance (NMR) data with synthesized standards.

Main Results:

• Identification of 11 distinct impurities in stressed CHG solutions.
• Six novel synthetic impurity standards were created.
• Degradation pathways were proposed for heat, light, and low pH stress.
• Parallels were drawn between HPLC-MS thermospray degradation and shelf-life degradation.

Conclusions:

• Comprehensive impurity profiling of CHG under stress conditions was achieved.
• Degradation mechanisms provide insight into CHG stability.
• The findings contribute to quality control and stability assessment of CHG formulations.