Development and in vitro evaluation of topically applied cinnamic acid formulations

Area of Science:

• Pharmaceutical Sciences
• Drug Delivery Systems
• Materials Science

Background:

• Cinnamic acid (CN) requires effective drug delivery systems for sustained release.
• Microencapsulation is a promising technique for controlling drug release profiles.
• Emulsion technology offers various platforms for drug formulation.

Purpose of the Study:

• To formulate microencapsulated cinnamic acid (CN) in various emulsion types (w/o, o/w, w/o/w).
• To compare the release profiles of microencapsulated CN with non-microencapsulated formulations.
• To evaluate the influence of formulation factors and membrane types on CN release.

Main Methods:

• Utilized an experimental design approach for formulation optimization.
• Employed cellulose acetate, cellulose nitrate membranes, and excised rat skin for release studies.
• Performed statistical analysis using repeated measures ANOVA and Bonferroni multiple comparisons test.

Main Results:

• A 2:1 core:wall ratio in microcapsules was found to be optimal for sustained release.
• Water-in-oil (w/o) emulsions with microencapsulated CN demonstrated effective sustained release.
• Water-in-oil-in-water (w/o/w) emulsions also provided prolonged release; oil-in-water (o/w) showed no significant difference.
• Excisied rat skin exhibited significantly different release profiles compared to synthetic membranes.

Conclusions:

• Microencapsulation of CN in w/o emulsions serves as an effective carrier for sustained release and drug protection.
• W/o/w emulsions are also viable for prolonged drug release, offering ease of preparation and application.
• The type of emulsion and release membrane significantly impacts cinnamic acid release kinetics.