Background: Adapalene is a promising third generation retinoid used in topical treatment of acne vulgaris. However, the major drawback associated with conventional topical therapy of Adapalene is the ‘retinoid reaction’ which is dose-dependent and characterized by erythema, scaling and burning sensation at the application sites. Microparticulate drug delivery can play a major role by targeting delivery, reducing side effects and offering better patient compliance.
Method: Adapalene microparticles were prepared using quasi emulsion solvent diffusion method. The effects of formulation variables including polymer ratios, amount of emulsifier, drug loading and process variables such as stirring time and speed on the physical characteristics of microparticles such as appearance, yield, size and drug release were investigated. The developed microparticles were characterized by DSC and SEM. Adapalene microparticles were incorporated into Carbopol 971 NF gel for ease of application.
Results: Adapalene microparticulate topical gel showed sustained drug release over 8 hours in in vitro studies. The amount of drug retained in the rat skin was higher in the microparticulate topical gel (227.43 ± 0.83 μg/cm2) as compared to the marketed formulation (81.4 ± 1.11 μg/cm2) at the end of study after 8 hours indicating localized and sustained drug action that can be useful in treating acne vulgaris. The safety of optimized Adapalene gel determined by skin irritation studies performed on Sprague Dawley rats showed no irritation.
Conclusion: Microparticles can provide promising carrier systems to deliver Adapalene, improving patient compliance due to enhanced skin deposition and providing localized action with reduced associated irritant effects.