Curcumin-loaded microemulsion: formulation, characterization, and in vitro skin penetration

Area of Science:

• Pharmaceutical Sciences
• Materials Science
• Dermatology

Background:

• Curcumin possesses valuable therapeutic properties but suffers from poor bioavailability and skin penetration.
• Microemulsions offer a promising delivery system to overcome these limitations due to their small droplet size and high surface area.

Purpose of the Study:

• To formulate curcumin in a microemulsion with high loading capacity.
• To enhance curcumin's skin penetration and therapeutic efficacy using microemulsion properties.

Main Methods:

• Curcumin was formulated into microemulsions using oleic acid, Tween® 80, and Transcutol® HP.
• Pseudo-ternary diagrams were used to map microemulsion formation areas.
• Characterization included physical properties and in vitro skin permeation studies.

Main Results:

• Stable microemulsions with varying globule sizes were successfully prepared.
• The optimal microemulsion (60 mg/mL curcumin loading) demonstrated significant skin penetration, reaching the viable epidermis.
• Curcumin was primarily localized in the epidermis (20-30 µm depth) after 24 hours.

Conclusions:

• Microemulsion formulation facilitates curcumin's passage into and through the skin.
• The targeted delivery of curcumin to the viable epidermis is beneficial for treating localized skin conditions.