Benzophenone-3 entrapped in solid lipid microspheres: formulation and in vitro skin evaluation.

Area of Science:

• Pharmaceutical Sciences
• Dermal Drug Delivery
• Materials Science

Background:

• Solid lipid microspheres (SLM) are lipid-in-water formulations.
• Benzophenone-3 (B-3) is a water-insoluble UVAB filter for dermal use.
• Investigating SLMs as carriers for lipophilic compounds is crucial for enhanced topical formulations.

Purpose of the Study:

• To evaluate the feasibility of using SLMs for dermal delivery of benzophenone-3 (B-3).
• To characterize SLMs loaded with B-3.
• To assess the in vitro percutaneous penetration of B-3 from SLMs.

Main Methods:

• SLMs were prepared using dispersion and homogenization techniques.
• Microsphere characterization involved polarizing and scanning electron microscopy.
• In vitro skin penetration studies were conducted using Franz cells.

Main Results:

• Spherical SLMs of 5-50 μm were successfully prepared.
• Maximum B-3 loading capacity was 5% at an 18% lipophilic phase.
• SLMs demonstrated reduced release and penetration of B-3 compared to free B-3 in oily solutions.

Conclusions:

• SLMs are a feasible and effective carrier system for lipophilic UV absorbers like B-3.
• The use of SLMs can control the release and penetration rate of UV filters.
• The developed SLM formulation is cosmetically acceptable, utilizing physiological and biodegradable lipids.