284 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS

RHEOLOGY OF MAS/XANTHAN GUM DISPERSIONS 285 after extended storage, have also been observed as an added benefit related to the non-thixotropic nature of the MAS-XG blends at the preferred 9:1 to 2:1 ratios. The balance of viscosity and yield value will enable such blends to be used in many applications at levels below 1%. These properties suggest particular utility for the MAS-XG combination in stabilizing free flowing lotions, suspensions, and liquid makeups. CONCLUSION Useful and interesting properties are obtained when magnesium aluminum silicate and xanthan gum are used in combination. Synergism in both viscosity and yield value can be obtained. The thixotropy imparted to aqueous systems by the mineral can also be minimized. Blends with magnesium aluminum silicate: xanthan gum ratios in the range of 9:1 to 2:1 are recommended for the best balance of viscosity, yield value, and flow. Such blends will be effective in stabilizing flowable lotions, suspensions, and makeups. REFERENCES (1) H. van Olphen, An Introduction To Clay Colloid Chemistry, (Wiley Interscience, New York, 1977) pp 92-110. (2) B.C. Carlson, VEEGUM in eye makeup, Am. Perf Cosmet., 86, 39-44 (March 1971). (3) B.C. Carlson, VEEGUM in cosmetic gels and sticks, Cosmet. Toiletries, 92, 81-86 (July 1977). (4) P. A. Ciullo, Magnesium aluminum silicate in water-in-oil emulsions, Drug Cosmet. Ind., 126, 50-56 (May 1980). (5) Xanthan Gum/Kdtrol/Kdzan a natural biopoOsaccharide for scientific water control, Second Ed., Kelco Div. of Merck Co., Inc. (6) D. A. Rees, Shapely polysaccharides, Biochem. J., 126, 257-273 (1972). (7) D. A. Rees, Biophysical Society Winter Meeting, London (1973). (8) A. Jeanes, Applications of extracellular microbial polysaccharide-polyelectrolytes: review of literature, including patents,J. Polym. Sci. Part C, Symp. No. 45, 209-227 (1974). (9) R. L. Bowles, R. ?. Davie and W. D. Todd, Interpretation of Brookfield viscosities, Mod. Plastics, 33, 140-148 (November 1955). (10) B. K. G. Theng, Formation andSProperties of Clay-Polymer Complexes, (Elsevier, New York, 1979) pp 243-261.