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Updated: Jun 28, 2026
16:24
Controlling the Size, Shape and Stability of Supramolecular Polymers in Water
Published on: August 2, 2012
Concentration dependent aggregation properties of chlorhexidine salts.
Pengyun Zeng1, Guifang Zhang, Aruna Rao
1Department of Pharmaceutics, University of Minnesota, 308 Harvard St. SE, Minneapolis, MN 55455, United States.
International Journal of Pharmaceutics
|October 18, 2008
Summary
Chlorhexidine (CHX) solubility varies with counterions; gluconate enhances solubility, while chloride limits it. This impacts sustained-release formulations for dental disinfection.
Area of Science:
- Chemistry
- Materials Science
- Biomedical Engineering
Background:
- Chlorhexidine (CHX) is an effective antiseptic for treating microbial infections.
- CHX binds to dentin, making it suitable for dental applications.
- Developing sustained-release formulations requires understanding CHX salt properties.
Purpose of the Study:
- To determine the solubility and aggregation properties of chlorhexidine (CHX) salts.
- To guide the development of sustained-release CHX formulations for long-term disinfection.
- To investigate the influence of different counterions on CHX solubility and aggregation.
Main Methods:
- UV spectrophotometry to quantify CHX concentration with varying counterions (chloride, acetate, gluconate).
- Light scattering to determine weight average molecular weight and aggregation.
- Proton NMR spectroscopy for solution concentration, chemical shift, and diffusion measurements (PFG-SE).
Main Results:
- CHX concentration was highly dependent on counterion type and concentration.
- Gluconate resulted in the highest CHX concentration, while chloride yielded very low concentrations.
- CHX-gluconate formed aggregates (dimers to pentamers), unlike CHX-acetate or CHX-chloride, which showed no aggregation.
- Solubilization of CHX-diacetate occurred within digluconate aggregates above the critical micelle concentration (CMC).
Conclusions:
- Low CHX concentrations in physiological chloride levels may hinder dental and slow-release applications.
- High CHX concentrations for sustained release require monomer concentrations exceeding self-association levels.
- Understanding counterion effects is crucial for optimizing CHX formulation efficacy.
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