Manufacturing of OTC acne products is both a science and an art. An OTC acne product must abide by the rules and regulations set in the Acne Monograph in the choice of an allowed active ingredient or combination of active ingredients and the allowable concentration ranges.
Amongst the approved OTC acne ingredients, BPO and SA are the most widely used. Both are topical comedolytics that help dry excess sebum and make the excreted sebum less sticky. This prevents occlusion of the pores and consequent formation of comedones. Topical comedolytics also cause sloughing of the stratum corneum and help remove existing sebum plugs along with loose keratinocytes. They also help normalize keratin turnover in the follicle (14). Interestingly, in the Final Acne Monograph, the agency notes that only BPO has known comedolytic activity and considers the other monograph ingredients as exfoliating agents that can evoke superficial peeling, thereby “aiding in unroofing superficial pustular lesions and causing spontaneous drainage” (15).
Benzoyl peroxide and SA come in a variety of products and in several different delivery systems, such as creams, washes, gels, and cleansing pads (16). Skin reactions to topical treatments may vary depending on the skin types. Thus, formulating the right OTC product that can work best for the majority of acne population is a formidable task. The main concern should be minimization of irritation on all skin types. The formulator should also take into account the time an individual has to care for the skin, the lifestyles of consumers, and the cost of individual products.
Another important consideration for formulation is the effects of the vehicle on the skin. Gels and solutions such as astringents can have higher alcohol contents and may increase the drying effect, while creams and lotions delivered in an emollient base tend to be moisturizing to the skin. “A proper vehicle is one that will deliver the drug to the site of action at a rate that will allow maximum benefit without causing or allowing toxic effects” (17). Given that all OTC acne drugs are keratolytics and can be somewhat drying and irritating, the ability of a vehicle that can mitigate the irritancy potential and allow delivery of the maximum drug benefits is all the more important.
What this also translates into is that in order to provide sustainable treatment benefits, OTC acne treatment should be developed in such a way that the consumers can and will like to use on a consistent, long-term basis. In other words, OTC acne products should be effective in delivering the clinical improvements as indicated, cause little or no irritation, be aesthetically pleasant, and be easy to use.