Gramicidin and chlorhexidine encapsulated in bicontinuous microemulsions: antimicrobial activity performance and...

Area of Science:

• Colloid and Surface Science
• Materials Science
• Pharmaceutical Sciences

Background:

• Antimicrobial peptides (AMPs) and antiseptics are crucial for combating antibiotic-resistant bacteria.
• Bicontinuous microemulsions (BMEs) offer potential as delivery systems for topical applications.
• Understanding the interaction between active agents and BME structure is vital for formulation efficacy.

Purpose of the Study:

• To investigate the utility of BMEs as carriers for gramicidin D (an AMP) and chlorhexidine (an antiseptic).
• To explore the impact of these agents on BME structure and dynamics.
• To evaluate the antimicrobial efficacy of BME formulations against skin-relevant bacteria.

Main Methods:

• Formulation of BMEs with gramicidin D and chlorhexidine in various systems.
• Characterization of BME structure and dynamics using small-angle neutron scattering (SANS).
• Bioassays on artificial skin to assess antimicrobial activity against antibiotic-resistant bacteria.

Main Results:

• Gramicidin D and chlorhexidine were successfully incorporated into BMEs at significant concentrations.
• Both solutes altered BME interfacial properties, decreasing surfactant activity and increasing fluidity in one system, while forming aggregates in others.
• BME formulations containing active agents showed enhanced bioactivity against bacteria, though overall efficacy was less than aqueous controls in some assays.

Conclusions:

• Antimicrobial peptides and antiseptics significantly influence BME structure and dynamics.
• The complex interactions necessitate careful formulation strategies for optimal antimicrobial delivery via BMEs.
• Further research is needed to optimize BME formulations for enhanced topical antimicrobial activity.