Novel anionic surfactant-modified chlorhexidine and its potent antimicrobial properties

Area of Science:

• Materials Science
• Chemistry
• Microbiology

Background:

• Chlorhexidine (CHX) is a widely used antiseptic, but its efficacy can be influenced by formulation.
• Surfactants can modify the properties and delivery of active pharmaceutical ingredients.
• Investigating novel salt forms of CHX with different counterions is crucial for optimizing its therapeutic potential.

Purpose of the Study:

• To synthesize and characterize a novel chlorhexidine salt, chlorhexidine dodecyl sulfate (CHX-DS).
• To evaluate the antibacterial activity and efficacy in reducing volatile sulfur compounds (VSCs) of CHX-DS compared to chlorhexidine gluconate (CHG).
• To explore the potential of CHX-DS as a functional material for drug delivery applications.

Main Methods:

• Single-crystal X-ray diffraction (SC-XRD) for structural elucidation.
• Nuclear magnetic resonance (NMR) spectroscopy (1H and NOESY) for structural and interaction analysis.
• Attenuated total reflectance Fourier-transform infrared spectroscopy (ATR-FTIR) for functional group identification.
• Minimum inhibitory concentration (MIC) assays against various bacterial strains.
• Qualitative release studies of CHX-DS incorporated into mesoporous silica nanoparticles (MSNs).

Main Results:

• The solid-state structure of CHX-DS was determined, revealing a 1:2 stoichiometric ratio of chlorhexidine cations to dodecyl sulfate anions.
• CHX-DS demonstrated broad-spectrum antibacterial activity with specific MIC values against *S. enterica*, *E. coli*, *S. aureus*, and *S. mutans*.
• CHX-DS showed superior efficacy in reducing VSCs compared to CHG and exhibited statistically significant efficacy enhancement in MIC assays for *E. coli* and *S. mutans* at 2.5 μM.
• Preliminary studies indicated CHX-DS can be incorporated into SBA-15 MSNs, suggesting potential for controlled release.

Conclusions:

• Chlorhexidine dodecyl sulfate (CHX-DS) represents a novel formulation of chlorhexidine with promising antibacterial properties.
• CHX-DS offers enhanced efficacy in reducing VSCs and improved antibacterial performance compared to conventional chlorhexidine gluconate (CHG).
• The incorporation of CHX-DS into mesoporous silica nanoparticles highlights its potential as a functional material for advanced drug delivery systems.