DISSOLVABLE ANTI-WRINKLE FILM 155 (7) H.J. Park, C. L. Weller, P. J. Vergano, and R. F. Testin, Permeability and mechanical properties of cellulose-based edible films,]. Food Sci., 58, 1361-1364 (1993). (8) M. L. Abella, Evaluation of the anti-wrinkle efficacy of adenosine-containing products using the FOITS technique, Int. J. Cosmet. Sci., 28, 447-451 (2006). (9) R. Bora, E. Kiheung, S. Yongin, and D. Kyunggi, Adenin, a new anti-wrinkle agent, IFSCC Conference, Seoul, Korea, 2003, abstract book poster 29. (10) S. Lieb, R. M. Szeimies, and G. Lee, Self-adhesive thin films for topical delivery of aminolevulinic acid, Eur. J. Pharm. Biopharm., 53, 99-106 (2002). (11) S. Nicoli, V. Amoretti, P. Colombo, and P. Santi, Bioadhesive transdermal film containing caffeine, Skin Pharmaco!. Physio!., 17, 119-123 (2004).

]. Cosmet. Sci.J 58, 157-171 (March/April 2007) Preparation and stability of cosmetic formulations with an anti-aging peptide M.A. RUIZ, B. CLARES, M. E. MORALES, S. CAZALLA, and V. GALLARDO, Departamento de Farmacia y Tecnologfa FarmaceuticaJ Facultad de FarmaciaJ Universidad de Granada! 10871 Granada, Spain. Accepted for publication November 21, 2006. Synopsis W tinkling of the skin is the most obvious sign of deterioration of the human body with age. This process involves a number of genetic, constitutional, hormonal, nutritional, and environmental factors, in addition to the influence of frequently repeated facial movements during laughing, smoking, etc. This article reviews the physiological basis and mechanism of action of the active cosmetic ingredient acetyl hexapeptide-8 (Argireline®). We prepared two formulations: an emulsion with an external aqueous phase for normal to dry skin, and a gel for oily skin. Laboratory analyses, rheology tests and in vitro release assays were used to evaluate the stability of these formulations for cosmetic treatment. INTRODUCTION The search for new compounds to prevent or attenuate skin aging and enhance self­ image (1) is a priority of current research on active cosmetics. Given the social impli­ cations surrounding physical appearance, we have undertaken work to investigate the treatment of facial expression wrinkles. Favorable results with botulin toxin infiltration led to the development of a new active principle with effects similar to the botox effect, named Argireline®, as an alternative to botulin um toxin. Unlike other creams developed to treat aging wrinkles, the formulas tested in this study are intended to treat expression wrinkles. Substances with a botox-like effect act upon the same phenomenon as botulin toxin, but via a different mechanism of action. To understand the mechanism of action of the formulas we tested, a brief review of how expression wrinkles are formed may be helpful. Expression wrinkles (2) form as a result of repeated muscle contraction caused by dermal atrophy and the appearance of hypodermal fibrosis (3). Facial movements cause cells of the dermis to contract and relax, and subject fibroblasts anchored by the network of Address all correspondence to M. A. Ruiz Martinez. 157