Ascorbic acid (vitamin C) is a water-soluble vitamin and a recognized antioxidant drug that is used topically in dermatology to treat and prevent the changes associated with photoaging, as well as for the treatment of hyperpigmentation. Ascorbic acid has neutralizing properties of free radicals, being able to interact with superoxide, hydroxyl and free oxygen ions, preventing the inflammatory processes, carcinogens, and other processes that accelerate photoaging in the skin. Current research focuses on the search for stable compounds of ascorbic acid and new alternatives for administration in the dermis. Unlike plants and most animals, humans do not have the ability to synthesize our own ascorbic acid due to the deficiency of the enzyme L-gulono-gamma-lactone oxidase, which catalyzes the passage terminal in the ascorbic acid biosynthesis. To deal with this situation, humans obtain this vitamin from the diet and/or vitamin supplements, thus preventing the development of diseases and achieving general well-being. Ascorbic acid is involved in important metabolic functions and is vital for the growth and maintenance of healthy bones, teeth, gums, ligaments, and blood vessels. Ascorbic acid is a very unstable vitamin and is easily oxidized in aqueous solutions and cosmetic formulations. Ascorbic acid is extensively used as an ingredient in anti-aging cosmetic products, as sodium ascorbate or ascorbyl palmitate. This review discusses and describes the potential roles for ascorbic acid in skin health and their clinical applications (antioxidative, photoprotective, anti-aging, and anti-pigmentary effects) of topical ascorbic acid on the skin and main mechanisms of action. Considering the instability and difficulty in administering ascorbic acid, we also discuss the importance of several factors involved in the formulation and stabilization of their topical preparations in this review.

Polyphenols comprise a number of natural substances, such as flavonoids, that show interesting biological effects. Among these substances is naringin, a naturally occurring flavanone glycoside found in citrus fruits and Chinese medicinal herbs. Several studies have shown that naringin has numerous biological properties, including cardioprotective, cholesterol-lowering, anti-Alzheimer’s, nephroprotective, antiageing, antihyperglycemic, antiosteoporotic and gastroprotective, anti-inflammatory, antioxidant, antiapoptotic, anticancer and antiulcer effects. Despite its multiple benefits, the clinical application of naringin is severely restricted due to its susceptibility to oxidation, poor water solubility, and dissolution rate. In addition, naringin shows instability at acidic pH, is enzymatically metabolized by β-glycosidase in the stomach and is degraded in the bloodstream when administered intravenously. These limitations, however, have been overcome thanks to the development of naringin nanoformulations. This review summarizes recent research carried out on strategies designed to improve naringin’s bioactivity for potential therapeutic applications.

Currently, biological drug therapy for ocular angiogenesis treatment is based on the administration of anti‐VEGF agents via intravitreal route. The molecules approved with this purpose for ocular use include pegaptanib, ranibizumab, and aflibercept, whereas bevacizumab is commonly off‐label used in the clinical practice. The schedule dosage involves repeated intravitreal injections of anti‐VEGF agents to achieve and maintain effective concentrations in retina and choroids, which are administrated as solutions form. In this review article, we describe the features of different anti‐VEGF agents, major challenges for their ocular delivery and the nanoparticles in development as delivery system of them. In this way, several polymeric and lipid nanoparticles are explored to load anti‐VEGF agents with the aim of achieving sustained drug release and thus, minimize the number of intravitreal injections required. The main challenges were focused in the loading the molecules that maintain their bioactivity after their release from nanoparticulate system, followed the evaluation of them through studies of formulation stability, pharmacokinetic, and efficacy in in vitro and in vivo models. The analysis was based on the information published in peer‐reviewed published papers relevant to anti‐VEGF treatments and nanoparticles developed as ocular anti‐VEGF delivery system.