Clinical efficacy assessment in photodamaged skin of 0.5% and 1.0% idebenone

Idebenone is an antioxidant lower molecular weight analogue of coenzyme Q10. Previously, idebenone was shown to be a very effective antioxidant in its ability to protect against cell damage from oxidative stress in a variety of biochemical, cell biological, and in vivo methods, including its ability to suppress sunburn cell (SBC) formation in living skin. However, no clinical studies have been previously conducted to establish the efficacy of idebenone in a topical skincare formulation for the treatment of photodamaged skin. In this nonvehicle control study, 0.5% and 1.0% idebenone commercial formulations were evaluated in a clinical trial for topical safety and efficacy in photodamaged skin. Forty-one female subjects, aged 30-65, with moderate photodamaged skin were randomized to use a blind labelled (either 0.5% or 1.0% idebenone in otherwise identical lotion bases) skincare preparation twice daily for six weeks. Blinded expert grader assessments for skin roughness/dryness, fine lines/wrinkles, and global improvement in photodamage were performed at baseline, three weeks and six weeks. Electrical conductance readings for skin surface hydration and 35 mm digital photography were made at baseline after six weeks. Punch biopsies were taken from randomly selected subjects, baseline and after six weeks, and stained for certain antibodies (interleukin IL-6, interleukin IL-1b, matrixmetalloproteinase MMP-1, collagen I) using immunofluorescence microscopy. After six weeks' use of the 1.0% idebenone formula, a 26% reduction in skin roughness/dryness was observed, a 37% increase in skin hydration, a 29% reduction in fine lines/wrinkles, and a 33% improvement in overall global assessment of photodamaged skin. For the 0.5% idebenone formulation, a 23% reduction in skin roughness/dryness was observed, a 37% increase in skin hydration, a 27% reduction in fine lines/wrinkles, and a 30% improvement in overall global assessment of photodamaged skin. The immunofluorescence staining revealed a decrease in IL-1b, IL-6, and MMP-1 and an increase in collagen I for both concentrations.

Idebenone: a new antioxidant - Part I. Relative assessment of oxidative stress protection capacity compared to commonly known antioxidants

Topical applications of skin care products containing antioxidants have become increasingly popular. Numerous studies have elucidated the biological effects of these substances. General antiaging effects, anti-inflammatory properties, photoprotective properties, and prevention of ultraviolet (UV) immunosuppression have been documented. However, a standardized method to characterize and compare the properties and oxidative stress protection capacity of antioxidants was lacking. A multistep in vitro process utilizing a variety of biochemical and cell biological methods combined with in vivo studies was designed to compare the oxidative stress protective capacity of commonly used antioxidants. Data were presented for L-ascorbic acid, dl-alpha-tocopherol, kinetin, dl-alpha lipoic acid, ubiquinone, and idebenone. Methods included using UV-induced radical trapping/scavenging capacity measured by photochemiluminescence, pro-oxidative systems (LDL-CuSO(4), microsome-NADPH/ADP/Fe(3+)) with measurement of primary and secondary oxidation products, UVB irradiation of human keratinocytes, and in vivo evaluation, using the human sunburn cell (SBC) assay. Correlation and trends between in vitro and in vivo results were established, and the standardized test protocol was used to quantify oxidative stress protection capacity of antioxidants. Summarizing and totaling the data equally weighted for each oxidative stress study, the overall oxidative protection capacity scores of 95, 80, 68, 55, 52, and 41 were obtained for idebenone, dl-alpha tocopherol, kinetin, ubiquinone, L-ascorbic acid, and dl-alpha lipoic acid, respectively. The higher the score, the more effective the overall oxidative stress protection capacity of the antioxidant became. This multistep protocol may serve as a standard in investigating and comparing new putative antioxidants for topical use as well as a valuable tool to assess the anti-inflammatory properties, photoprotective properties, and prevention of UV immunosuppression of topical antioxidants.

Photoprotective and antiinflammatory effects of topical glycolic acid

BACKGROUND

Concerns about photosensitizing potential of alpha hydroxy acids have been expressed. A previous study, however, reported topical glycolic acid showing the opposite potential, that is, photoprotective. This study was designed to test the antiinflammatory and photoprotective capabilities of glycolic acid.

OBJECTIVE

The effects of short-wave ultraviolet light (UVB) on skin treated with glycolic acid were evaluated in two different studies at two different locations.

METHODS

In the first study the antiinflammatory potential of topical glycolic acid was tested on erythematous templates on the backs of human volunteers. Erythema was induced by exposure to three times the minimum erythema dose (MED) of UVB. Glycolic acid cream in an oil-in-water vehicle at 12% partially neutralized with ammonium hydroxide to a pH of 4.2 was applied to the template beginning 4 hours postirradiation four times a day. A second template on the same subject was used as a vehicle control. After 48 hours a marked reduction of erythema was noted when compared with the vehicle control site. In the second study, four test sites were exposed to UVB light in the following manner. Site 1 was a nontreated control site and was used to establish the MED for the subjects being tested; site 2 was also exposed to a MED series but was treated 24 hours postirradiation for 7 days with two glycolic acid-based products (cleanser and oil-free moisture lotion, both containing 8.0% glycolic acid at a pH of 3.25); site 3 was treated first with the two glycolic acid-based formulas for 3 weeks prior to being exposed to UVB light; and site 4 was treated as outlined in site 3, with the inclusion that the site was chemically peeled for 6 minutes (with a 50% glycolic solution at a pH of 2.75) 15 minutes prior to UVB exposure.

RESULTS

When UVB-burned skin was treated with glycolic acid daily for 7 days (site 2), a 16% reduction in irritation was observed compared to nontreated skin (site 1), implying that skin healed sooner when treated with glycolic acid. When a comparison of nontreated skin was made to skin treated with glycolic acid for 3 weeks prior to UVB exposure (site 1 vs site 3), a sun protection factor (SPF) of 2.4 was achieved. When a comparison of skin treated for 3 weeks was made to skin treated for 3 weeks and chemically peeled (site 3 vs site 4) the data implied that the chemical peel reduced the SPF value of skin treated with glycolic by approximately 50%, however, an SPF trend of 1.7 was still obtained when compared with untreated skin. CONCLUSIONS. The studies demonstrated that topical glycolic acid provides a photoprotective effect to pretreated skin yielding an SPF of approximately 2.4. In addition, when glycolic acid is applied to irradiated skin, it accelerates resolution of erythema. The data obtained from both studies support the hypothesis that glycolic acids acts as an antioxidant.

Clinical and histological effects of glycolic acid at different concentrations and pH levels

BACKGROUND

Much has been said about the effects of glycolic acid with little scientific evidence to substantiate the findings. OBJECTIVE. This study reports on the clinical and histological effects of glycolic acid at pH levels 3.25, 3.80, and 4.40, and at 3.25%, 6.50%, 9.75%, and 13.00% on ichthyotic/xerotic skin.

METHODS

Product treatment consisted of a 2-week washout period followed by 3 weeks of product application (BID) with A 1-week regression period. Shave biopsies and clinical evaluations for dryness, moisturization, and transepidermal water loss were made at baseline, 1, 2, and 3 weeks of use, and at the regression period.

RESULTS

Clinically, ichthyotic/xerotic skin was normalized with histologic evidence of stratum corneum thinning, viable epidermal thickening, and marked increases in glycosaminoglycan and collagen content.

CONCLUSION

All pH levels and concentrations demonstrated significant improvement in the condition of the skin with trends implying that increasing the pH increases efficacy.

Teratological assessment of five oxidative hair dyes in the rat

The oxidative dyes, 4,4'-diaminodiphenylene sulfate, N'-(2-hydroxyethyl)-4-nitro-O-phenylenediamine, N,N-dimethyl-p-phenylenediamine, 2,3-dihydroxynaphthalene, and resorcinol, were evaluated for teratogenic potential. Dyes were administered by gavage to pregnant Sprague-Dawley rats on gestation Days 6 through 15 at doses ranging from 12.5 to 500 mg/kg. No overt signs of toxicity were observed during the treatment period. A significant reduction in mean maternal weight gain was noted during the treatment period at the high dose for 4,4'-diaminodiphenylene sulfate, N'-(2-hydroxyethyl)-4-nitro-O-phenylenediamine, and 2,3-dihydroxynaphthalene. The high dose for N,N-dimethyl-p-phenylenediamine and resorcinol, which exceeded a 100-fold exaggeration of human exposure, did not produce a significant reduction in maternal weight gain. An evaluation of fetal external, visceral, and skeletal anomalies revealed no statistically significant differences between dye-treated and vehicle control groups. Administration of 100,000 units of vitamin A, the positive control, on Day 9 of gestation resulted in a significant increase in abnormal fetuses.

Teratological assessment of the oxidative dye 4-methyl-N-ethylamino phenol sulfate

The oxidative dye 4-methyl-N-ethylamino phenol sulfate was evaluated for teratogenic potential. The dye was administered by gavage to pregnant Sprague-Dawley rats at dose levels of 300, 600, and 1200 mg/kg on gestation days six through fifteen. No signs of toxicity were observed during the treatment period. A significant reduction in mean maternal weight gain was noted during treatment at the high dose level of 1200 mg/kg. The test material did not produce embryotoxic nor fetal toxic effects at dose levels utilized. Evaluation of fetal external, visceral, and skeletal anomalies revealed no statistically significant differences between dye treated and control groups. Oral exposure of dams to the positive control, Vitamin A, resulted in a significant increase in the number of litters with abnormal fetuses.