98 JOURNAL OF COSMETIC SCIENCE DVNAMIC INDENTOMETRIC ANALYSIS OF HAIR ASSEMBLIES Janusz Jachowicz, Ph.D. Better Cosmetics, LLC Dynamic mechanical analysis is frequently employed to study polymeric materials. It is a convenient method to determine elastic and viscous properties of a tested sample in one experiment. The measurements of solid materials yield parameters such as storage and loss modulae, which are related to elastic deformation and viscous energy dissipation, respectively. Similar principles are used in dynamic rheological measurements of liquids. The fundamental properties of interest in this case are shear modulus and viscosity. Dynamic rheological methods are widely used in cosmetic science to characterize cosmetic formulations, thickeners, surfactant solutions, etc. Dynamic mechanical analysis was also used for characterization of hair (rheovibron) and skin (gas­ bearing electrodynamometry). In the context of hair research, published dynamic studies were limited to longitudonal deformations and the determination of dynamic Young's modulae. There has also been a study of wet hair subjected to bending deformation in water at various pH [ 1]. In this work we have employed dynamic mechanical analysis to study the behavior of random or organized assemblies of various types of hair such as Caucasian, Chinese, and African. Hair fibers in such systems can assume various positions and orientations, and can shift versus each other during deformation. This contributes to energy dissipation and increases the values of loss modulae. Fiber arrangements were prepared by setting wet hair to impart curling characterized by different geometrical dimensions. Straight­ hair assemblies with controlled distribution of orientations as well as fiber assemblies in the form of omega-loops were also investigated. Dynamic mode of operation of a Texture Analyzer (Texture Technologies Corp.) was employed with the deformations ranging from 0.01 mm to 1 mm and frequencies from 1 Hz to 100 Hz. FFT Image Analysis was used to quantify the shape and orientation of fibers. [1] - J.Jachowicz, Methodologies for evaluating hair-care products, Cosmetics& Toiletries, 113 (6), 45 (1998).

2007 ANNUAL SCIENTIFIC MEETING MAXIMIZING ANTI-DANDRUFF SHAMPOO PERFORMANCE WITH DEPOSITION TECHNOLOGY 99 Wing Li, Xiaodong Zhang, Ph.D., Anita Protonentis, Diane Frank and Jennifer Amos Amerchol/DOW, 171 River Road, Piscataway, NJ 08854 Summary: Zinc pyrithione (ZPT) is a commonly used anti-dandruff agent for scalp treatment which is most often delivered from shampoo systems. Anti-dandruff shampoos with conditioning benefits dominate the current market. Cationic polymers are widely used to facilitate deposition of benefit agents from cleansing products. Previous studies have documented that polymeric deposition efficacy depends on the molecular weight, charge density and the hydrophobicity of the polymer as well as the nature of the substrate. Today, most of the commercial products are optimized to provide maximum conditioning performance for hair. However, the deposition target for the anti­ dandruff agent is on scalp. The current technology to measure anti-dandruff effectiveness relies on clinical data which is time consuming and expensive. A new, simple in vitro method has been developed that simulates the shampooing process while simultaneously monitoring ZPT deposition on both hair and scalp using acid extraction and measuring zinc by atomic absorption spectroscopy (AAS). Results indicate that most ZPT deposits onto the hair instead of scalp from the current commercial products. This new technique is simple and can be used as screening tool during new product development to maximize the performance of 2-in-1 anti-dandruff shampoos. Background: Dandruff is a chronic scalp condition characterized by excessive flaking and it is a problem in approximately 30% of the world's population. Anti-dandruff shampoo containing anti-fungal ingredients, such as Zinc Pyrithione (ZPT) are widely used to treat this condition. The amount of active ingredient delivered to the scalp from the shampoo directly relates to the antidandruff efficacy. 2-in-1 anti-dandruff shampoos are becoming more popular because they provide the additional benefit of an effective conditioner. Cationic polymers are well known to provide conditioning benefit and facilitate deposition of benefit agents from cleansing product. Through the flocculation mechanism, the benefit agents are entrapped in/on the coacervate, polymer-surfactant complex, and deposited onto different targets, hair and scalp. For example, silicone oil is deposited onto hair for conditioning benefit and ZPT is delivered onto scalp for antidandruff purpose. Clinical studies are currently the method of choice to measure antidandruff efficacy. This method is time consuming and expensive, therefore it is not suitable to be used as screening tool for new product development. We developed a new, simple in vitro method to simulate the shampooing process while simultaneously monitoring ZPT deposition on both hair and scalp. Experimental Section: Commercial products: Product A (1 ¾ZPT/Cationic Polymer A), Product B (1 % ZPT/Cationic PolymerB) Formulation: 0.25% cationic polymer with 1 % to 3% ZPT, 2% Ethylene Glycol Distearate, 1 % Silicone Emulsion (0.5um), 0.21 % Citric Acid, 0.4% DMDM Hydantoin in 15.5% Sodium Laureth Sulfate and 2.6% Disodium Cocoamphodiacetate. The control formulation does not contain cationic polymer.