EASY STATISTICAL TESTS 107 +++ 11 1I II II +++ II II II

.T. Soc. Cosmetic Chemists, 19, 109-117 (Feb. 5, 1968) Studies of Glyceryl Monostearate* RAYMOND M. CORNISH, B.S.t Presented May 2, 1967, New York City Synopsis--The properties of commercial glyceryl monostearate have been investigated in order to understand more fully its long term behavior as a raw material and as an emulsion component. Emphasis has been on physical properties as studied by X-ray diffraction, differential thermal analysis, and optical microscopy. Several manifestations of slow changes in the crystalline state which are time- and temperature-dependent have been observed. Applica- tion of these results to a specific emulsion problem is discussed. INTRODUCTION The work described in this paper had its origin in a study which was done to determine the mechanism of breakdown of a dispersion formulation. That earlier work had established that the principal source of instability in this formulation was the glyceryl monostearate (GMS). The studies were extended in an effort to enlarge our under- standing of the properties of this component (GMS) and thus gain better control of formulations in which it is used. The usual quality control procedures were followed for monitoring GMS as it was used in production. These called for certain standards of iodine number, melting range, monoester content, etc. This grade of glyceryl monostearate was known to increase in acid value over a period of time and so a limit to storage time was adopted to keep this parameter at a low value. In spite of these checks, the use of GMS was not always predictable. * We wish to thank Carter Products, Division of Carter-Wallace, for the support and permission to publish this work. • Arthur D. Little, Inc., 15 Acorn Park, Cambridge, Mass. 02140. 109