The role of the vehicle in combination acne therapy.

The choice of vehicle is an important consideration in acne therapy. Because the epidermal barrier may be impaired by both the underlying disorder and the use of some topical treatments for acne, vehicle formulations that minimize barrier impairment, help to restore barrier function, and limit signs and symptoms of skin irritation are valuable components of acne therapy, especially early in the course of treatment or with combination regimens. Formulations with ingredients that provide moisturization, such as humectants and emollients, are ideal in the management of acne. Tretinoin microsphere and tretinoin polyolprepolymer-2 are vehicle modifications designed to release tretinoin in a slow controlled manner, thus minimizing the potential for irritation associated with standard tretinoin formulations. A combination of clindamycin and benzoyl peroxide in a water-based gel formulated with the humectant glycerin and the emollient dimethicone has been shown to improve skin tolerability and overall patient preference compared with the same active ingredients formulated without the special additives that provide moisturization.