Ocular irritation reversibility assessment for personal care products using a porcine corneal culture assay.

Personal care product manufacturers have used a broad spectrum of alternative ocular irritation assays during the past two decades because these tests do not require the use of live animals, they provide reliable predictive data, and they are relatively inexpensive to conduct. To complement these assays, the ex vivo Porcine Corneal Opacity Reversibility Assay (PorCORA) was recently developed using a corneal culture model to predict reversibility of ocular irritants. Three commercially available consumer products (a shampoo, a hair color glaze, and a hair colorant system containing 12% hydrogen peroxide) were each tested in two PorCORA study replicates in order to assess potential ocular damage reversibility for surfactant-, propylene carbonate-, and peroxide-based formulations, respectively. Under the exaggerated, in vitro study conditions, the surfactant-based shampoo may cause irreversible porcine corneal damage (histological changes in the epithelial squamous cell and/or basal cell layers), whereas the hair color glaze and 12% hydrogen peroxide product caused fully reversible ocular irritation (microscopic changes only in the superficial squamous cell layer). The hair color glaze and peroxide product results correlate with established in vivo data for similar compounds, but the shampoo results contradicted previous BCOP results (expected to be only a mild irritant). Therefore, although the PorCORA protocol shows promise in predicting the extent and reversibility of potential ocular damage caused by accidental consumer eye exposure to personal care products, the contradictory results for the surfactant-based shampoo indicate that more extensive validation testing of the PorCORA is necessary to definitively establish the protocol's reliability as a Draize test replacement.

Ability of moisturizers to reduce dry skin and irritation and to prevent their return.

Assays of moisturizer efficacy have traditionally focused on a moisturizer's ability to alleviate dry skin. More recently, a moisturizer's ability to prevent primary irritation has been recognized. To assess and compare the ability of moisturizers to alleviate skin dryness and primary irritation, as well as prevent their return, four controlled-application clinical (in vivo) studies were carried out: hand-wash test, regression test, reduction in pre-existing irritation study, and prevention-of-irritation studies. Overall conclusions were confirmed in a home-use clinical (validation) study of people suffering from mild eczema. The controlled in vivo studies demonstrate that: (a) a moisturizer can alleviate skin dryness and irritation, and prevent their return; and (b) the efficacy of different moisturizers can be differentiated, based on their composition. The home-use study results demonstrated that the most effective moisturizer identified by the controlled-application studies was highly effective against the signs of eczema. In vivo modeling of moisturizer efficacy enables assessment and optimization of different benefits separately, while predicting the quantitative and perceived (observed) relevance of the benefits the moisturizer delivers to consumers.

Comparison of age-related changes in wrinkling and sagging of the skin in Caucasian females and in Japanese females.

We compared age-related changes in wrinkles in eight areas of facial skin (forehead, glabella, upper eyelid, corner of the eye, lower eyelid, nasolabial groove, cheek, and corner of the mouth) and sagging in the subzygomatic area of Caucasian females and of Japanese females. The subjects studied included 85 healthy Caucasian females (ages 20-69 years) living in Cincinnati in the U.S. and 70 Japanese females (ages 20-69 years) living in Tokyo. Photos of the face in frontal and in oblique 45 degrees views were analyzed. Wrinkles in the face and sagging in the subzygomatic area were graded on Japanese photoscales, respectively, by the same experienced observer. The wrinkle score increased with age in all eight areas of the face examined in Caucasian females as well as in Japanese females. In the group aged 20-29 years, the wrinkle score in each area was significantly higher in Caucasian females than in Japanese females. The wrinkle scores in the forehead, glabella, upper eyelid, and corner of the eye were similar at advanced ages between the two groups, while the wrinkle scores in lower areas of the face (lower eyelid, nasolabial groove, cheek, and corner of the mouth) were markedly higher in Caucasian females than in Japanese females in each age group, and reached an upper limit at advanced ages in Caucasian females. The sagging score also increased with age in Caucasian females as well as in Japanese females. The sagging score was significantly higher in Caucasian females than in Japanese females in the groups aged 40 years or more. These results suggest more marked wrinkle formation in all areas of the face in younger age groups of Caucasian females living in North America than in Japanese females living in Tokyo. In particular, Caucasian females showed marked age-related wrinkle formation in the lower areas of the face, probably due to sagging in the subzygomatic area, which suggests a higher susceptibility to sagging in the subzygomatic area of Caucasian females.

Screening topical antipruritics: a histamine-induced itch human model.

Itch is a subjective symptom; its magnitude (intensity) may be only estimated by the reports of patients or volunteers. We utilized a comparative screening method to identify and quantify the efficacy of topical antipruritics with a histamine-induced itch human model. Ten individuals responsive to histamine-induced itch sensation were enrolled. Both forearms served as test sites. Each test site was treated randomly either by histamine injection only or pretreated with a coded candidate formula for 30 min and then a histamine injection. Itch was experimentally induced in each test site by the intracutaneous injection of 100 microg histamine dihydrochloride dissolved in 1 ml normal saline. Itch magnitude was measured each minute after histamine injection for 20 min with a magnitude visual analogue scale. Itch duration was also recorded. Formulation D significantly (p < 0.05) decreased itch magnitude (within a 20-min test period), from 2.6 +/- 2.1 cm (mean +/- SD) to 2.2 +/- 2.1 cm (mean +/- SD) when compared to its vehicle control; it also significantly (p < 0.05) shortened itch duration (15.0 +/- 7.4 min; mean +/- SD) in comparison with its vehicle control (20.3 +/- 7.0 min; mean +/- SD). Of all the formulations tested, formulation D was the most effective antipruritic in decreasing histamine-induced itch. This method may act as a simple and robust screening procedure when evaluating potential antipruritics and allow a comparison among products. Until validated with disease-induced itch, e.g., atopic dermatitis, the model should be considered screening in nature.