Profile of depigmenting cosmetics and dermatological products on the market

The skin is the largest and most exposed organ of the human body, therefore subject to diseases and alteration of its appearance. Among these alterations, the cutaneous hyperchromia may be cited. Currently, the market offers numerous products with depigmenting action to the treatment of such disorders. The aim of this work was to analyze depigmenting products commercialized in establishments in the city of Bento Gonçalves (RS, Brazil) and websites of cosmetic companies. It was found 45 products with depigmenting action and, from these, 59 different active agents were identified. The main active compounds found were kojic acid, arbutin, ascorbic acid, hydroquinone and glycolic acid. Another observed data was that in 78% of the studied products the active substances were being used in combination. The most used vehicles were also studied as a reference to the use of sunscreen in the treatment of cutaneous hyperchromia. The present work had identified in the market a variety of products with depigmentation action and, because of this, it aims to serve as a reference to the healthcare professionals, especially at the prescribing moment, looking for the best results, with regards to treatment efficiency and safety.(AU)

Glutathione as a skin whitening agent: Facts, myths, evidence and controversies.

Glutathione is a low molecular weight thiol-tripeptide that plays a prominent role in maintaining intracellular redox balance. In addition to its remarkable antioxidant properties, the discovery of its antimelanogenic properties has led to its promotion as a skin-lightening agent. It is widely used for this indication in some ethnic populations. However, there is a dichotomy between evidence to support its effi cacy and safety. The hype around its depigmentary properties may be a marketing gimmick of pharma-cosmeceutical companies. This review focuses on the various aspects of glutathione: its metabolism, mechanism of action and the scientifi c evidence to evaluate its effi cacy as a systemic skin-lightening agent. Glutathione is present intracellularly in its reduced form and plays an important role in various physiological functions. Its skin-lightening effects result from direct as well as indirect inhibition of the tyrosinase enzyme and switching from eumelanin to phaeomelanin production. It is available in oral, parenteral and topical forms. Although the use of intravenous glutathione injections is popular, there is no evidence to prove its effi cacy. In fact, the adverse effects caused by intravenous glutathione have led the Food and Drug Administration of Philippines to issue a public warning condemning its use for off-label indications such as skin lightening. Currently, there are three randomized controlled trials that support the skin-lightening effect and good safety profi le of topical and oral glutathione. However, key questions such as the duration of treatment, longevity of skin-lightening effect and maintenance protocols remain unanswered. More randomized, double-blind, placebo-controlled trials with larger sample size, long-term follow-up and well-defi ned effi cacy outcomes are warranted to establish the relevance of this molecule in disorders of hyperpigmentation and skin lightening.

Permeação cutânea in vitro do ácido kójico / Kojic acid in vitro percutaneous penetration study

Desordens no processo melanogênico podem causar as hiperpigmentações, sendo a de maior freqüência o melasma. O ácido kójico é um dos despigmentantes tópicos utilizados no tratamento destas hipercromias. A ação de um produto dermatológico deve ser tópica, não devendo atingir níveis sistêmicos. Um dos fatores que pode definir o nível de ação, tópica ou sistêmica, são os excipientes das formulações. Neste contexto, o presente trabalho teve por objetivo avaliar o grau de permeação cutânea in vitro, utilizando célula de FRANZ modificada, de uma formulação em relação a uma solução tampão pH 7,4, ambas contendo ácido kójico na concentração de 2 por cento. A quantificação do ácido kójico permeado e retido na membrana foi realizada por método espectrofotométrico no ultravioleta. O estudo in vitro mostrou que a absorção do ácido kójico da formulação apresentou cinética de pseudo 1ª ordem (no intervalo de 1 a 8 horas) e, conseqüentemente, menor fluxo através da membrana natural (pele da orelha de porco) e maior retenção cutânea, enquanto que o ácido kójico da solução tampão pH 7,4 apresentou cinética de ordem zero e, conseqüentemente, maior fluxo e menor retenção. Este resultado indicou que a formulação desenvolvida mostrou-se adequada para a veiculação do ácido kójico, tendo em vista que o órgão alvo é a pele.

Disorder of the tirosinase biosynthesis process can result on hiperpigmentations, like the frequently found melasma. The kojic acid is one of the depigmenting topic agent utilized in the handling of these hipercromies. The action of a dermatologic product should be topic, should not reach systemic levels. One of the factors that is able to defined the level of action, topic or systemic, is the vehicle. In this contest, the present work had for objective evaluate the rank of in vitro cutaneous permeation, in the cell of FRANZ modified, of a formulation regarding a buffered solution 7.4, both containing kojic acid (2 percent). The kojic acid percutaneous penetration and retention was quantified by a spectrophotometric in the ultraviolet method. The in vitro study showed that the absorption of kojic acid from the formulation presented kinetic of pseudo 1st order (in the break from 1 to 8 hours) and consequently smaller stream through the natural membrane (skin from the ear of pig) and bigger cutaneous retention, while the kojic acid from the buffered solution pH 7.4 presented kinetic of zero order and consequently bigger stream and smaller retention. This result indicated that the formulation developed can be used as a vehicle for kojic acid, having in mind that the target tissue is the skin.

Melasma

Melasma is a common acquired symmetric hypermelanosis characterized by irregular light to dark brown macules and patches on sunexposed areas of the skin. Its histopathologic characteristics are important for treatment. Melasma is characterized by epidermal hyperpigmentation possibly by both the increased number of melanocytes and the increased function of melanogenic enzymes over the dermal solar changes. Until now, curative measures are not available for melasma. Current therapies include topical agents (retinoic acid, hydroquinone, steroids), peeling (Combes solution, glycolic acid, TCA), and lasers(Co2, Erbium-Yag, Q-switched).