PENETRATION OF LANOLIN 225 1 m o I I I I 2 3 4 5 mg Lanolin Figure 3. Calibration curve for lanolin determination. I

226 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS removed visibly decreased as a function of depth, as would be expected from the other results. A secondary observation arising from the work was that test sites treated with lanolin prior to tape stripping healed significantly more quickly than untreated sites. This observation is being investigated further in a follow-up study. REFERENCES (1) G. Imokawa and M. Hattori, A possible function of structural lipids in the water-holding properties of the stratum corneum, J. Invest. Dermatol., 84, 282-284 (1985). (2) G. Imokawa, S. Akasaki, A. Kawamata, S. Yano, and N. Takaishi, Water-retaining functions in the stratum corneum and its recovery properties by synthetic pseudoceramides, J. Soc. Cosmet. ½hem., 40, 273-285 (1989). (3) A. J. I. Ward and C. du Reau, Modelling the permeability properties of skin, Cosmet. Toiletr., 105, 53-59 (1990). (4) E. W. Clark, New concepts of lanolin. In-Cosmetics Seminar, Birmingham NEC, England (March 1990). (5) E. W. Clark, Estimation of the general incidence of specific lanolin allergy,J. $oc. Cosmet. Chem., 26, 323-335 (1975). (6) E. W. Clark, E. Cronin, and D. S. Wilkinson, Lanolin with reduced sensitizing potential, Contact Dermatitis, 3, 69-74 (1977). (7) H. Ippen, Investigations on contact allergy to woolwax. 5th session of the International Contact Dermatitis Group, Barcelona (1980). (8) E. W. Clark, A. Blondeel, E. Cronin, J. A. Oleffe, and D. S. Wilkinson, Lanolin of reduced sensitizing potential, Contact Dermatitis, 7, 80-83 (1981). (9) B. Edman and H. Moeller, Testing a purified lanolin preparation by a randomized procedure, Contact Dermatitis, 20, 287-290 (1989). (10) K. Okamoto, Studies on the quantity and chemical composition of surface lipids of human scalp and hair, J. Dermatol, (Tokyo), 7, 85-99 (1985). (11) E. V. Truter, Wool Wax Chemistry and Technology (Cleaver-Hume Press Limited, London, 1956), p. 185. (12) C. S. King, S. P. Barton, S. Nicholls, and R. Marks, The change in properties of the stratum corneum as a function of depth, Brit. J. Dermatol., 100, 165-172 (1979). Appendix I: DERIVATION OF A CALIBRATION CURVE FOR THE SPECTROPHOTOMETRIC DETERMINATION OF LANOLIN MATERIALS AND EQUIPMENT ß Chloroform AR ß Acetic anhydride AR ß Sulphuric acid, concentrated AR ß Anhydrous lanolin BP (Westbrook) ß 50-ml graduated burette ß 50-ml graduated stoppered glass cylinders ß 1-ml graduated pipette ß Optical glass cells, 20-mm path length ß Spectrophotometer, Philips PU 8650 PROCEDURE A standard solution of lanolin in chloroform was prepared with a concentration of 0.37 gl-•. Eight different measured volumes of this standard solution were run from the