Targeted Topical Delivery of Retinoids in the Management of Acne Vulgaris: Current Formulations and Novel Delivery Systems

Abstract

Acne vulgaris is a common inflammatory pilosebaceous condition that affects 80–90% of adolescents. Since the introduction of tretinoin over 40 years ago, topical retinoid products have been a mainstay of acne treatment. The retinoids are very effective in addressing multiple aspects of the acne pathology as they are comedolytic and anti-inflammatory, and do not contribute to antibiotic resistance or microbiome disturbance that can be associated with long-term antibiotic therapies that are a common alternative treatment. However, topical retinoids are associated with skin dryness, erythema and pain, and may exacerbate dermatitis or eczema. Thus, there is a clear need to target delivery of the retinoids to the pilosebaceous units to increase efficacy and minimise side effects in surrounding skin tissue. This paper reviews the current marketed topical retinoid products and the research that has been applied to the development of targeted topical delivery systems of retinoids for acne.

An overview of treatment options for mild‐to‐moderate acne based on American Academy of Dermatology, European Academy of Dermatology and Venereology, and Italian Society of Dermatology and Venereology guidelines

“…It has anti-inflammatory action by inhibiting neutrophil chemotaxis and limiting damage induced by free radicals. 1,13 It was formulated with a higher percentage, 7.5% in a single daily dose, in the treatment of acne in patients over 12 years of age. 13 This posology minimizes systemic exposure of the drug, which is 25% to 40% lower than the 5% formulation.…”

“…Acne is a chronic inflammatory disease of the skin, affecting the pilosebaceous unit. 1 It has a multifactorial pathogenesis, with a typical onset in the puberal phase and a male prevalence. In adolescents the incidence of this condition might reach 87%, 2 although it is also found in adulthood, with a female prevalence.…”

“…The characteristics of the lesions are closely related to the various stages of the disease. 1 Typical lesions are comedones, small papules centered by a white point (close comedones) or by a black point (opened comedones), indicative of a dilatation of the follicular opening such as to allow the oxidation of the lipid content that clinically will appear black (mild acne). The initial lesions may worsen, with inflamed papules and pustules (moderate acne) and inflamed cystic nodules (severe acne).…”

Improved Biosafety and Transdermal Delivery of Aconitine via Diethylene Glycol Monoethyl Ether-Mediated Microemulsion Assisted with Microneedles

“…The unencapsulated drug molecules were separated in an ultrafiltration tube (MWCO: 10 kDa) by centrifugation at 3000× g, and then assayed by HPLC. The entrapment efficiency and drug loading were respectively calculated according to the following Equations (1) and (2):…”

“…Aconitine is an active ingredient isolated from the herb Aconitum carmichaeli Debx., which is commonly used as an analgesic in traditional Chinese medicine, and transdermal administration can improve its safety [1]. Microemulsions, nanovehicles for transdermal drug delivery, involve isotropic, transparent, and thermodynamically stable dispersion systems spontaneously formed by the interaction between water, oil, surfactant, and co-surfactant in appropriate proportions [2]. Microemulsions have low surface tension, and they easily moisturize the skin and disrupt the firm structure of the stratum corneum [3].…”