]. Cosmet. Sci., 58, 99-107 (March/April 2007) Wool peptide derivatives for hand care C. BARBA, S. MENDEZ, A. RODDICK-LANZILOTTA, R. KELLY, J. L. PARRA, and L. CODERCH, IIQAB (CSIC), jordi Girona 18-26, 08034 Barcelona, Spain (C.B., S.M., J.L.P., L.C., Canesis Network Ltd, Private Bag 4749, Christchurch, New Zealand (A. R.-L.), and Keratec limited, Springs Road, Lincoln, Canterbury, New Zealand (R.K.). Accepted for publication January 23, 2007. Synopsis Hands experience much greater wear and tear during normal daily routines compared with most other parts of the body, and thereby demand specific needs from cosmetics targeted at hand care. Keratin proteins are the major structural component of the outer layers of the skin. In this work a novel keratin fraction from wool, which has high cystine content present in the S-sulphonated form, has been developed to target hand care applications. In vivo long-term studies were performed to evaluate the water-holding capacity and elasticity of hand skin following topical application of keratins. Moreover, protection of healthy skin against detergent-induced dermatitis was evaluated after topical application of the keratin-active formulation. Significant results in the measured biophysical parameters were found, which indicated an improvement in the skin's water-holding capacity, hydration, and elasticity for volunteers with dry skin as a result of the keratin peptide treatment. Results also indicated that the keratin peptide treatment can prevent some of the damaging effects associated with surfactant exposure. INTRODUCTION Keratin proteins are used extensively by the body as a major structural component of the outer layers of the skin. These keratin proteins, with a high content of the amino acid cystine, provide a greater structural stability to chemical agents and solvents than many other proteins types. Wool is predominantly composed of keratin proteins that combine to give it desirable properties such as strength, insolubility, and moisture regain. Dif­ ferent classes of keratin proteins are represented in the complex macromolecular struc­ ture, each of which has specific functions and characteristics. The daily wear and tear experienced by the hands creates specific needs to be met by the formulators of hand care cosmetics. Issues such as moisturization and elasticity of hand skin are often more severe than issues experienced by other parts of the body. In this study, a novel keratin protein fraction from wool has been developed to target hand care applications. The keratin peptide studied is a specific fraction ot the wool fiber, which has been enzymatically hydrolyzed to give a peptide in the range of 6-8 99

100 JOURNAL OF COSMETIC SCIENCE amino acids (MW by SDS-PAGEl000D), which has high cystine content present in the S-sulphonated form. This unique functionality maintains the antioxidant activity of the amino acid cysteine. As a hydrolysate, keratin peptide can penetrate into the skin and increase moisturization, protecting the hands. The aim of this work was to study the efficacy of this new keratin active in a hand cream formulation. The effect of this keratin active when applied topically on a long-term basis to undisturbed hand skin on properties such as water-holding capacity and elasticity was determined. Finally, protection of healthy skin against detergent-induced dermatitis was evaluated after topical application of the keratin active formulation. MATERIALS AND METHODS CHEMICALS Chemicals employed were keratin peptide (Keratec Limited, New Zealand) sodium lauryl sulphate, SLS (Merck, Darmstadt, Germany) and Cromadol GTCC, Polawax NF, stearic acid, Crodacol C90 EP, Propylparaben, Ultrez 21, acylate crosspolymer, and methylparaben (Croda, UK). SAMPLE PREPARATION Two hand creams were used both were made from the formulation given below. The keratin cream was prepared by adding 3% keratin peptide (as supplied, i.e., 0.3% active) and the base cream by addition of 3% deionized water. Base hand cream formulation. The formulation comprised Crodamol GTCC (10.0% w/w), Polawax NF (5 .0% w/w), stearic acid (3.0% w/w), Crodacol C90 EP (2.0% w/w), Propylparaben (0.25% w/w), Ultrez 21 (8.0% w/w), acrylate crosspolymer 2%, Meth­ ylparaben (0.20% w/w), and deionized water (to 100.0% w/w). SUBJECTS Sixteen healthy volunteers (all females) phototype III-IV-V with a mean age of 33 ± 8 years (range 24-50 years) participated in both studies (Table I). All subjects were advised to avoid topical drugs or moisturizers on the tested zones for a week prior to the experiments. To obtain reliable measurements, the volunteers were acclimatized for 15 min in a conditioned room (20°C, 60% RH) before the experiments. Subjects were classified into group 1 (dry skin, mean initial capacitance 45) and group 2 (hydrated skin, mean initial capacitance 45) based on initial skin capacitance measurements, following the advice given by the instrument company (Courage & Khazaka). BIOPHYSICAL MEASUREMENTS Skin hydration was determined using a Corneometer CM 85 (Courage & Khazaka), which measures skin capacitance in arbitrary units (au). Transepidermal water loss (TEWL), which indicates the barrier function of skin, was measured using a Tewameter TM 210 (Courage and Khazaka). Elasticity was determined by a Cutometer SEM 575