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

Abstract

Objective

Formulation of curcumin in a microemulsion with a high loading capacity and that favors its penetration into the skin.

Significance

Take advantage of the properties of microemulsions to promote the penetration of curcumin into the skin, with the aim of enhancing its therapeutic effects.

Methods

Curcumin was formulated in microemulsions based on oleic acid (oil phase), Tween® 80 (surfactant), and Transcutol^® HP (cosurfactant). The microemulsion formation area was mapped by constructing pseudo-ternary diagrams for surfactant:co-surfactant ratios 1:1, 1:2, and 2:1. Microemulsions were characterized through measurements of specific weight, refractive index, conductivity, viscosity, droplet size, and in vitro skin permeation studies.

Results

Nine microemulsions were prepared and characterized, showing clear, stable formulations with globule size dependent on the proportion of the components. The microemulsion with the highest loading capacity (60 mg/mL), based on Tween^® 80, Transcutol^® HP, oleic acid, and water (40:40:10:10) was able to penetrate the viable epidermis, finding a total amount of curcumin in the receptor medium at 24 h of 10.17 ± 9.7 µg/cm². The distribution of curcumin in the skin, visualized by confocal laser scanning microscopy, showed that the maximum amount was located between 20 and 30 µm.

Conclusion

The inclusion of curcumin in a microemulsion allows its passage into and through the skin. The localization of curcumin, especially in the viable epidermis, would be important for those cases where local conditions are sought to be treated.

Keywords:

• Microemulsion
• curcumin
• skin
• in vitro permeation studies
• confocal laser scanning microscopy

Correction Statement

This article has been corrected with minor changes. These changes do not impact the academic content of the article.

Acknowledgment

The authors are grateful for the financial support provided through the projects PAPIIT IN204022 and PAPIIT IN223620.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by Dirección General de Asuntos del Personal Académico, Universidad Nacional Autónoma de México [PAPIIT IN204022] and Facultad de Estudios Superiores Cuautitlán, Universidad Nacional Autónoma de México [CI2209].