Amphotericin B topical microemulsion: formulation, characterization and evaluation.

Area of Science:

• Pharmaceutical Sciences
• Drug Delivery Systems
• Dermatology

Background:

• Invasive fungal infections pose a significant therapeutic challenge.
• Amphotericin B (Amp B) is a critical antifungal agent with limitations in conventional formulations.
• Development of advanced drug delivery systems is crucial for improving Amp B efficacy and patient outcomes.

Purpose of the Study:

• To formulate and characterize a microemulsion (ME) of Amphotericin B (Amp B) for enhanced topical delivery.
• To evaluate the in vitro antifungal efficacy and skin permeation of the developed ME formulation.
• To assess the stability and safety profile of the Amp B-loaded ME.

Main Methods:

• Screening of oil, surfactant, and co-surfactant for microemulsion formation.
• Construction of pseudo-ternary phase diagrams to identify microemulsion existence regions.
• Characterization of optimized ME (ME 7) including globule size, polydispersity index, pH, and conductance.
• In vitro drug permeation studies across excised rat skin.
• Antifungal activity testing against Trichophyton rubrum and stability studies.

Main Results:

• An optimized microemulsion (ME 7) containing 0.1% Amp B was successfully developed.
• ME 7 exhibited a small globule size (84.20 nm) and narrow size distribution (PDI 0.164).
• The formulation showed a 2-fold increase in drug permeation compared to the plain drug solution.
• Significant in vitro antifungal activity against Trichophyton rubrum was observed.
• The formulation demonstrated good stability at 2-8°C and room temperature for three months.

Conclusions:

• The developed Amphotericin B microemulsion (ME 7) is a promising drug delivery system for treating invasive fungal infections.
• Enhanced skin permeation and potent antifungal activity suggest improved therapeutic potential.
• The formulation's stability and safety profile support its viability as an alternative Amp B therapy.