Читать книгу Surface Science and Adhesion in Cosmetics - Группа авторов - Страница 13

Rebecca Barresi and I-Chien Liao*

L’Oreal Research and Innovation Clark, NJ, USA

Abstract

The lips are two pliable and mobile muscular folds that surround the oral cavity and assist in a variety of functions which enable both human survival and communication. In addition to their functional purpose, the lips are frequently cosmetically enhanced, in terms of color and gloss, through the application of lipsticks. Understanding both the biophysical and surface properties of lips is crucial for the successful formulation and development of lipsticks, particularly those with long-wear or transfer-resistant claims. Various in vitro methods provide a clear insight as to the stability, physical properties, and visual characteristics of a lipstick formulation, but a correlation between such results and consumer use experience is still lacking.

This book chapter provides an overview of the lip anatomy and lip surface properties, which can be used to provide a general knowledge for lipstick formulation. While much is known in regards to the structure and functionality of the lip tissue, obtaining further knowledge can assist in the development of superior performing lipstick formulations. Classic in vitro test methods for long-wear lipsticks, in addition to such test results correlations with consumer sensory testing, are also discussed. It is important to note that although there is an abundance of in vitro methods available in order to characterize long-wear and transfer-resistant lipsticks, there is still a definite need to develop new methods that better correlate with consumer experience. Existing methods have the potential to be further improved with new knowledge of lip properties and use of better test substrates to illustrate the benefits of new product innovations.

Keywords: Lip anatomy, lip biophysical properties, lip surface properties, long-wear lipstick, in vitro evaluation, consumer sensory testing