Microsphere based improved sunscreen formulation of ethylhexyl methoxycinnamate.

Area of Science:

• Materials Science
• Pharmaceutical Sciences
• Cosmetic Science

Background:

• Ethylhexyl methoxycinnamate (EHM) is a common UV filter in sunscreens.
• EHM can suffer from poor photostability and reduced effectiveness over time.
• Encapsulation in microspheres offers a potential solution to improve EHM's performance.

Purpose of the Study:

• To prepare and characterize polymethylmethacrylate (PMMA) microspheres loaded with EHM.
• To evaluate the impact of EHM-loaded PMMA microspheres on sunscreen efficacy and photostability.
• To optimize formulation parameters for improved sunscreen performance.

Main Methods:

• EHM-loaded PMMA microspheres were synthesized using the emulsion solvent evaporation method.
• Microsphere characterization included scanning electron microscopy (SEM) for morphology and laser diffraction for particle size.
• In vitro drug release, photostability (thin-layer chromatography), sun protection factor (SPF), and minimum erythema dose (MED) were assessed.

Main Results:

• Optimized PMMA microsphere formulations demonstrated significantly improved SPF values (over 16.0) compared to free EHM (SPF 4.66).
• The EHM:PMMA ratio influenced drug release rates, with a 1:3 ratio showing the slowest release.
• Enhanced photostability and approximately four-fold increase in sunscreen efficacy were observed with encapsulated EHM.

Conclusions:

• PMMA microspheres effectively enhance the photostability and efficacy of EHM as a sunscreen agent.
• Encapsulation of EHM in PMMA microspheres presents a promising strategy for developing advanced sunscreen formulations.
• The developed microsphere-based sunscreen formulation offers superior protection compared to conventional EHM formulations.