FLUORIDE ION FROM TOOTHPASTE 541 Zusammenfassung Im Verlauf dieser Arbeit werden die Bedingungen zur Trennung yon Fluoridionen in Zahnpasten durch Mikrodiffusion untersucht. Diese Technik wird gest6rt durch die Anwesenheit bestimmter Ionen wie Aluminium und Silikat. Literatur (1) K. J. Obrink, A modified conway unit for microdiffusion analyse, Biochem. J. 59, 134 (1955). (2) R. J. Hall, The spectrophotometric determination of submicrogram amounts of fluorine in biological specimens, Analyst 88, 76 (1963). (3) A.G. Cumpston and B. D. Dinman, A modified diffusion method for the determination of urinary fluoride, Am. Ind. Hyg. Assoc. J. 26, 461 (1965). (4) M. Hanocq, Contribution • l'•tude analytique de dhriv•s fluorbs. Application & l'analyse pharmaceutique. 1971 (Ed. Arscia Bruxelles). (5) M. Hanocq, Etude de la microdiffusion de l'ion fluorure sous forme de fluorure d'Hydro- g•ne, Mikrochim. Acta 729 (1973).

]. Soc. Cosmet. Chem., 27, 543-553 (November 1976) Sorption of A Cationic Polymer by Stratum Corneum JOSEPH A. FAUCHER, Ph.D. and E. DESMOND GODDARD, Ph.D.* Presented, in part, May 30, 1975, SCC Seminar, St. Louis, Mo. Synopsis: A study was made of the SORPTION of a CATIONIC CELLULOSE POLY- MER from aqueous solutions by several types of MAMMALIAN STRATUM CORNEUM. The effects of surfactants and other additives were investigated, as well as were the in- fluence of concentration and molecular weight of the polymer. Considerably more ma- terial is sotbed than can be accounted for by postulating monolayer coverage of the sub- strate. The data were found to be explained better by a mechanism of diffusion of the polymer into the outer layers of the stratum corncure than by multilayer absorption. INTRODUCTION It has been known for some time that cationic surfactants and polymers are quickly bound to the skin and tenaciously held. However, data previously available in the literature (1-3) are only qualitative, and give litfie insight into the mechanism of adsorption. Some preliminary kinetic observations from this laboratory have been reported earlier (4) they dealt with the sorption by *Union Carbide Corp., Tarrytown Technical Center, Tarrytown, N.Y. 10591. 543