Liposomes as alternative vehicles for sun filter formulations

Area of Science:

• Dermatology
• Cosmetic Science
• Pharmaceutics

Background:

• Percutaneous absorption of sun filters is crucial for efficacy.
• Conventional oil/water emulsions have limitations in delivering lipophilic sun filters.
• Liposomes offer potential for enhanced delivery and formulation.

Purpose of the Study:

• To investigate the impact of different liposome lipid compositions on ethylhexyl methoxycinnamate percutaneous absorption.
• To compare in vitro and in vivo methodologies for assessing skin absorption.
• To evaluate liposomes as alternatives to conventional emulsions for sun filter formulations.

Main Methods:

• Preparation of three liposome types: unsaturated phosphatidylcholine (PC), saturated phosphatidylcholine (HPC), and wool lipid mixture (IWL).
• In vitro and in vivo studies to measure percutaneous absorption of ethylhexyl methoxycinnamate.
• Correlation analysis between in vitro and in vivo results.

Main Results:

• PC liposomes, due to their liquid crystalline state, significantly enhanced skin penetration.
• HPC and IWL liposomes, similar to stratum corneum lipids, reduced skin penetration, indicating barrier reinforcement.
• A good correlation was observed between in vitro and in vivo absorption data.

Conclusions:

• Liposome structure and lipid composition critically influence percutaneous absorption of lipophilic sun filters.
• PC liposomes are effective for enhancing skin penetration.
• HPC and IWL liposomes can strengthen the skin barrier, serving as viable alternatives to traditional emulsions for lipidic sun filters.