Evaluation of a hydroquinone-free skin brightening product using in vitro inhibition of melanogenesis and clinical reduction of ultraviolet-induced hyperpigmentation.

BACKGROUND AND OBJECTIVE: Skin lightening preparations are used by people all over the world for a diverse range of dermatologic indications. Hydroquinone (HQ) is the gold standard and remains the only prescription product available in the United States for the treatment of generalized facial hyperpigmentation. Irritation and the risk of exogenous ochronosis are the main adverse effects for concern. Therefore, there has been a constant search for new treatment alternatives. Understanding the molecular mechanisms involved in pigmentation has resulted in the development of a series of formulations that utilize a multimodal treatment approach. These proprietary formulas combine skin lightening agents that act via different mechanisms of action. The actives included 4-ethoxybenzaldehyde (anti-inflammatory and prostaglandin E2 suppressor), licorice extract (tyrosinase inhibitor), tetrahexyldecyl ascorbate (antioxidant), niacinamide (melanosome transport inhibitor), ethyl linoleate (tyrosinase inhibitor; enhances turnover of epidermis), hexylresorcinol (tyrosinase inhibitor), and retinol (tyrosinase transcription inhibitor; enhances turnover of epidermis). METHODS: Select formulations were tested in several studies using the MelanoDerm™ Skin Model (MatTek Corporation, Ashland, MA) to assess the ability of the product to reduce melanin production and distribution. A single-center, double-blind comparison clinical study of 18 subjects was conducted to evaluate the efficacy of the product in reducing ultraviolet-induced hyperpigmentation. Test sites were irradiated with 1.0, 1.5, 2.0, and 2.5 minimal erythema doses. After 5 days, to allow for pigmentation development, the product or 4% HQ cream was applied to the respective test sites, once daily for 4 weeks. Chroma Meter measurements (L* brightness) and standardized digital photographs were taken of the test sites twice a week. RESULTS: The test product resulted in greater reduction in melanin as measured by melanin content and histological staining compared with the positive control in the MelanoDerm Skin Model. The product also demonstrated statistically significant reductions in pigmentation compared with baseline (all P ≤.0001) at the end of the clinical study, and produced greater increases in L*, compared with 4% HQ. Results from these studies indicate that a product designed to affect multiple pathways of melanogenesis and melanin distribution may provide an additional treatment option beyond HQ for hyperpigmentation.

Formulation optimization, skin irritation, and efficacy characterization of a novel skin-lightening agent.

BACKGROUND: Skin-lightening preparations are used by people all over the world for a diverse range of dermatologic indications. The gold standard treatment for skin lightening is with hydroquinone but has been controversial because of the presence of several side effects. Therefore, there has been a constant search for developing new treatment alternatives. Furthermore, the new amendments and bans on animal testing by ECVAM have made the three-dimensional models like EpiDerm(™) and MelanoDerm(™) increasingly popular. OBJECTIVE: This work aims at the formulation development for a new skin-lightening agent, SMA-012, followed by testing for skin irritation and efficacy. METHODS: Formulation parameters such as concentration of SMA-012, amount of ethanol, effect of permeation enhancers and pH were first optimized using Franz cell experiments. Tape stripping and underlying skin assays were performed to analyze the amounts of SMA-012 in different layers of skin. The irritation potential and efficacy of the screened formulation were evaluated using Epiderm(™) and Melanoderm(™) models. RESULTS: Skin permeation experiments suggested that concentrations of 0.1% SMA-012, 35% ethanol, and pH of 8.5 to be the best formulation characteristics. This particular formulation was found to be nonirritant for short-term exposure, when tested in Epiderm(™) model and also significantly effective in decreasing the amount of melanin in pigmented skin equivalent models. CONCLUSION: SMA-012 shows a good promise as a skin-lightening agent for cosmetic and therapeutic applications. Additionally, our study demonstrates the application of skin equivalent models as alternatives to animal testing in studying the regulation of skin pigmentation.

Synergistic Combination of an In-office Procedure and Home Regimen for the Treatment of Facial Hyperpigmentation.

Hyperpigmentation disorders, such as melasma and solar lentigines, pose a significant treatment challenge for most patients. Combining a series of in-office procedures, such as chemical peels and light- and laser-based treatments, with maintenance therapies have been shown to provide greater efficacy than one treatment alone. However, receiving multiple in-office procedures may be cost prohibitive for patients. A series of eight case studies were conducted to evaluate the efficacy and tolerability of a novel treatment regimen combining one in-office superficial chemical peel procedure followed by a 12-week topical maintenance program consisting of micro-entrapped 4% hydroquinone, tri-retinol, and sunscreen with sun protection factor (SPF) 30+. Patients presented with Fitzpatrick skin types II and III and mild-to-moderate solar lentigines and/or melasma on their facial skin. Physician-graded overall improvement in hyperpigmentation, standardized photography, and patient satisfaction were evaluated at Weeks 4, 8, and 12. At Week 12, all eight patients demonstrated improvements of at least 25 percent in overall facial hyperpigmentation, with six of the patients demonstrating a 50- or 75-percent overall improvement. One hundred percent of the patients rated their experience with the novel treatment regimen as "excellent" or "good" reflecting high patient satisfaction. Standardized photographs also support the physician and patient findings. Results from these case studies demonstrate that this unique treatment regimen combining one in-office procedure followed by 12 weeks of topical maintenance therapy, may provide an effective, simple, and cost-effective option for patients with facial hyperpigmentation.

A randomized, double-blind, controlled comparative trial of the anti-aging properties of non-prescription tri-retinol 1.1% vs. prescription tretinoin 0.025%.

Vitamin A and its derivatives (commonly termed retinoids) are widely used in topical anti-aging products. Certain retinoids such as retinol and its esters are available without a prescription, while others such as tretinoin are available only via prescription. A randomized, double-blind, controlled clinical study was conducted to compare the efficacy and tolerability of a tri-retinol 1.1% gradual release cream vs. tretinoin 0.025% cream in females with mild-to-moderate facial photodamage. Subjects applied the test product to the entire face in the evening after cleansing in a progressively increasing frequency starting twice weekly for the first week, followed by three times weekly during the second week and then daily as tolerated for the third week and beyond. Treatment was continued for a total of three months. Clinical evaluations and standardized digital photographs were performed at baseline and after four, eight, and 12 weeks of treatment. Self-assessment questionnaires were completed by the subjects at four, eight, and 12 weeks to assess perceived efficacy of the test products. Thirty-four subjects (16: tri-retinol and 18: tretinoin) completed the study. Both test products significantly improved signs of photodamage, including fine and coarse periocular wrinkles, skin firmness, skin tone, mottled pigmentation, tactile roughness, overall photodamage and global photodamage improvement. There were no significant differences in efficacy between the two products for these assessments. The adverse effects (which were graded as mild or less) were those typically seen with topical retinoids. Subjects reported >93 percent overall satisfaction with both products at weeks 8 and 12.