Individual sol-gel microencapsulation of benzoyl peroxide and tretinoin enables controlled release onto the skin.

A combination of benzoyl peroxide (BPO) and tretinoin is recommended for treating acne; however, concurrent administration can be irritating, and coformulation is prevented by BPO-mediated oxidation of tretinoin. In rosacea, benzoyl peroxide has been shown to be efficacious; however, its use has been limited by poor tolerability. To overcome these limitations, the active ingredients can be encapsulated within silica microcapsules.

Silica-based microencapsulation used in topical dermatologic applications.

Microencapsulation has received extensive attention because of its various applications. Since its inception in the 1940s, this technology has been used across several areas, including the chemical, food, and pharmaceutical industries. Over-the-counter skin products often contain ingredients that readily and unevenly degrade upon contact with the skin.

Microencapsulated Benzoyl Peroxide and Tretinoin for the Treatment of Acne Vulgaris: Results from a Phase 2 Multicenter, Double-Blind, Randomized, Vehicle-Controlled Study.

This phase 2, 12-week, multicenter, randomized, double-blind, active- and vehicle-controlled (VC), parallel-group trial assessed the efficacy and safety of silica encapsulated benzoyl peroxide BP (E-BP), two concentrations of silica encapsulated tretinoin (E-ATRA) and their combinations (TWIN high and low) vs VC in 726 males and females ≥9 years of age with moderate-to-severe inflammatory facial acne. The co-primary efficacy endpoints were Investigators Global Assessment (IGA) success rate ("clear" or "almost clear") and changes from baseline in inflammatory and non-inflammatory lesion counts. TWIN high and low were each significantly superior vs VC for IGA success at 12 weeks (39.

A look at emerging delivery systems for topical drug products.

The introduction of new topical drugs based on new chemical entities has become a rare event. Instead, pharmaceutical companies have been focused on reformulating existing drugs resulting in an ever-growing number of topical drug products for every approved drug substance. In light of this trend, soon reformulations may not be as rewarding to their sponsors as they are today unless they offer a substantial improvement over other formulations of the same drug substance and the same indication, namely improved efficacy over existing drugs, reduced side effects, unique drug combinations, or applicability for new indications.