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. The US Food and Drug Administration has approved 2 products using this technology, a combination of encapsulated benzoyl peroxide and encapsulated tretinoin product for acne vulgaris and encapsulated benzoyl peroxide to treat inflammatory lesions in rosacea. The active ingredients are released through small channels in the silica shell, gradually releasing the active ingredients to the skin. This study describes the stability and release profiles of encapsulated tretinoin and encapsulated benzoyl peroxide from the silica shell in physiologically relevant conditions and provides differentiation from traditional formulations.

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. Enclosing these substances within a silica shell can enhance their stability and better regulate their delivery onto and into the skin. Silica microencapsulation uses silica as the matrix material into which ingredients can be embedded to form microcapsules. The FDA recognizes amorphous silica as a safe inorganic excipient and recently approved two new topical therapies for the treatment of rosacea and acne. The first approved formulation uses a novel silica-based controlled vehicle delivery technology to improve the stability of two active ingredients that are normally not able to be used in the same formulation due to potential instability and drug degradation. The formulation contains 3.0% benzoyl peroxide (BPO) and 0.1% tretinoin topical cream to treat acne vulgaris in adults and pediatric patients. The second formulation contains silica microencapsulated 5.0% BPO topical cream to treat inflammatory rosacea lesions in adults. Both formulations use the same amorphous silica sol-gel microencapsulation technology to improve formulation stability and skin compatibility parameters.

Impact of Topical Vehicles and Cutaneous Delivery Technologies on Patient Adherence and Treatment Outcomes in Acne and Rosacea.

Objective: Topical therapies remain the mainstay in treating patients with acne and rosacea. However, emerging real-world evidence demonstrates that desired treatment outcomes might not be achieved if patient satisfaction and adherence are low. Poor tolerability of active drug(s) and vehicle components and/or the drug delivery system could negatively influence adherence. Additionally, adherence might be lower with complex treatment regimens involving the application of multiple topical formulations. Optimizing vehicle tolerability and simplifying regimens that use fixed-dose combinations may improve treatment outcomes, better patient satisfaction, and reduce overall treatment costs. This qualitative review discusses several innovative drug delivery technologies and formulations aimed at improving patient satisfaction and adherence. Methods: The authors conducted a search of current and emerging topical drug delivery technologies used in clinical studies, reviewed primary literature on the chemical characteristics of topical dosage forms, and compared the impacts on treatment outcomes for acne and rosacea. Results: This article provides insight into innovative vehicles and drug delivery systems that have emerged allowing for fixed-dose combinations of incompatible active drugs and improving the tolerability of historically irritative active ingredients. Limitations: Further research is needed to fully highlight the impact of patient satisfaction and modern topical formulations on adherence and treatment outcomes. Conclusion: Drug microencapsulation is a delivery technology that has enabled development of a topical fixed-dose combination of benzoyl peroxide and tretinoin preventing the oxidation of tretinoin by benzoyl peroxide and improving the tolerability of the active ingredients.

Tretinoin Review With Newer Formulations: Providing Effective and Tolerable Solutions in Clinical Practice.

Topical tretinoin has historically been limited by poor tolerability and molecular instability. Research advances have enhanced its efficacy and tolerability, along with reducing oxidation and photodegradation. By overcoming historical limitations, tretinoin use can be extended to patient populations and clinical situations previously not suitable. This review discusses historical limitations of tretinoin, methods employed to overcome those limitations, use within clinical practice, and new formulations of tretinoin for the treatment of acne. J Drugs Dermatol. 2023;22(1):35-40. doi:10.36849/JDD.7146.

Structure elucidation of silica-based core-shell microencapsulated drugs for topical applications by cryogenic scanning electron microscopy.

We present here a technology to microencapsulate drugs by the sol-gel process, and cryo-SEM methodology that allows the nanostructural characterization of the formed capsules in their native state without any artifacts, related to their drying prior to imaging. The methodology utilizes three signals generated by the electron beam scanning the specimen: Secondary electrons, backscattered electrons, and x-rays. The first gives topographical information of the fracture-surface of the thermally-fixed specimen, the second gives contrast between elements of different atomic numbers, and the third allows the identification of those elements. Combined, the three signals provide full microstructural characterization of the studied specimen. Using this methodology, we were able to demonstrate that the sol-gel technology does indeed enable the encapsulation of two hydrophobic active molecules with a silica shell. This technology allows the active ingredient in the drug product to slowly migrate from the microcapsule onto the skin, thus obtaining the desired effect with minimal side-effects, as was exhibited in several clinical studies. The successful application of the cryo-SEM methodology in this case, demonstrates that it can be used to characterize a wide range of liquid-phase suspensions, in their native state, with minimal specimen preparation or imaging artifacts.