POLYQUATERNIUM-24/AMYLOSE COMPLEX 337 are summarized in Table I. The emulsion samples were made using a Talboy overhead stirrer at 15 rpm, and the viscosity of the samples was measured using a standard Brookfield DV-II+ viscometer, using spindle # 3 at 25øC. The oven samples were placed in a Blue M © Stabil-Therm oven, and the photos of formulations were taken via a Polaroid camera attached to an Olympus AH-2 model microscope. RESULTS AND DISCUSSION FORMATION OF OIL SUSPENSIONS An initial study was done to examine the ability of the aqueous polyquaternium-24 and amylose blend to suspend water-insoluble oils and solids by using various conditioning and emollient oils as well as titanium dioxide at 1, 5, and 10 wt % concentrations. The oils and solids were directly dispersed without strict control of biological conditions into 1% aqueous mixtures of the complex at 25øC (the complex itself must be created at higher temperatures) (22). The samples were then left undisturbed for six weeks at room temperature. The samples were visually inspected weekly for signs of incompatibility. The results of this initial study appear in Table II. Several of the emulsified samples remained clearly suspended at room temperature for six weeks. In particular, the emulsified silicon oils showed good resistance to oil and water partitioning. Microscopic examination after two weeks of one such 10% emulsion con- taining cyclomethicone is shown in Figure 1. The appearance of the various-sized oily droplets is evident in the photo. Samples of emulsions prepared using polyquaternium- 24 without the carefully blended amylose separate in a matter of days. The combination of the hydrophobic, cationic cellulose ether and amylose is clearly needed to maintain stable suspensions. It appears that the polyquaternium-24/amylose complex can suspend oils at room temperature at oil concentration levels at least as high as 10% without separation between the oil and water phases even after a six-week time period. We also examined the suspension of micronized TiO 2 in the complex. Figure 2 shows the fine dispersion of micronized TiO2 in the complex. This suspension also contained Table I Experimental Raw Materials INCI name Trade name Company Dimethicone Amersil © OSi Cyclomethicone Amersil VS © OSi Hydroxylated milk glycerides Cremerol HMG © Amerchol Polyquaternium-24 Quatrisoft © Polymer LM-200 Amerchol Isononyl isononanoate Salacos © 99 Nisshin Caprylic captic triglyceride Myritol © 318 Henkel Hydrogenated polyisobutene Panalene © Amoco Chemical Methyl gluceth- 10 Glucam © E- 10 Amerchol Diazolidinyl urea Germaben © II-E Sutton Laboratories DMDM hydantoin Glydant © Lonza Glycerin Glycerin Mallinckrodt Titanium dioxide Titanium dioxide Aldrich Amylose Amylose Sigma Chemical

338 JOURNAL OF COSMETIC SCIENCE Table II Results of a Six-Week, Room-Temperature, Emulsion-Stability Study of Various Oils and Solids Suspended in the Aqueous Polyquaternium-24/Amylose Complex Weight Week Week Week Week Week Week Emulsified component percent 1 2 3 4 5 6 Mineral oil Isononyl isononanoate Dimethicone Cyclomethicone Caprylic capric triglycerides Hydrogenated polybutene Titanium dioxide ]_ ß ß ß ß ß ß 5 ß ß ß ß ß SU 10 ß ß ß ß ß ß 1 ß ß SU SU SU SU 5 ß ß ß SU SU SU 10 ß ß ß ß ß ß 1 ß ß ß ß ß SU 10 ß ß ß ß ß ß 10 ß ß ß ß ß ß 1 ß ß SU U U U 5 ß ß SU U U U 10 ß ß SU U U U 5 ß ß ß ß ß SU 10 ß ß ß ß ß ß 1 ß ß ß SU SU U 5 ß ß ß ß ß ß 10 ß ß ß ß ß ß Slightly unstable (SU): Material is starting to separate. Unstable (U): Material has separated into two distinct phases. (*) indicates a stable emulsion. approximately 1% dimethicone, the droplets appearing as dark circles against the white TiO 2 particles. What is particularly intriguing is the apparent ability of the complex to prevent the TiO 2 and the oil from agglomerating. The TiO2 remains well dispersed in the mixture. PREPARATION OF SKIN LOTION FORMULATIONS USING THE POLYQUATERNIUM-24/ AMYLOSE COMPLEX Following the completion of the initial oil-suspending study, a prototype skin lotion formulation was developed using the polymer complex (Table III). The simple prototype formulation was developed by taking advantage of the functional attributes of various well-known skin conditioners. Hydroxylated milk glycerides and glycerin are excellent emollients and humectants, respectively. Dimethicone oil is the primary skin condi- tioner, but the polyquaternium-24 also has demonstrable feel properties. Methyl glu- ceth-10 was added to impart rheological control to the slightly pituitous polyquater- nium-24/amylose complex. These formulations impart a soft, lubricious feel to the skin with little tackiness during drying. Once dried, the formulations leave a soft afterfeel. The formulations showed no signs of pilling upon application, an occurrence sometimes noted in anionic poly(acry- late) thickeners. We investigated different application methods, including pump sprays