2001 ANNUAL SCIENTIFIC SEMINAR 347 1. Lactic Acid AHA's such as lactic acid are known to increase the rate of cell renewal by reducing corneocyte adhesion that promotes exfoliation of the cells on the surface of skin. Changes in the size of squamous cells can be used as an index of change in cell renewal rate. To determine the impact that polyester structure has upon the delivery of lactic acid to the SC, an in-vivo human panel test was conducted that focused upon differences in comparative cytology, which correlated to desquamation rates 7. Various polyesters were tested in formulations containing 10% undissociatad lactic acid, along with a control without the polyester. Cell biopsies were taken every 7 days up to 28 days. The cells were then sized, averaged, and compared to the baselines (Fig. 3). Another separate skin whitening study was conducted with lactic acid and the best performing polyester from the previous comparative cytology study hydroxyl terminated, 800 MW (TL-8). This study was a 42- day human clinical study, where panelists applied test formulations with and without polyester at different concentrations (5.0 and 2.5%). The relative pigmentation of the sites was rated weekly. The same formulations were used for this study as were utilized in the comparative cytology study (Fig. 4). 2. Hydroquinone This clinical human panel 28-day study was conducted to examine the effect of polymeric esters upon the skin whitening effect of formulations containing 2% hydroquinone. The test formulations consisted of a control formula with 2% hydroquinone, a formula containing 2% hydroquinone + 5% fatty alkyl terminated, 800 MW polyester (TC-8) and a formula containing 2% hydroquinone + 5% hydroxyl terminated, 800 MW polyester (TL-8). The products were applied to the panelists' forearms once daily, and the pigmentation of the sites rated weekly (Fig. 5). 3. Magnesium Ascorbyl Phosphate (MAP) Another skin whitening study was conducted with MAP and the best performing polyester from the hydroquinone study, TL-8. Two formulation variations were tested which contained 2.5% polyester one contained 5% MAP, and the second contained 3% MAP. The control formulation had no polyester, but contained a high level of MAP at 10%. Test products were applied to the forearms of panelists twice daily for 28 days, and observed weekly for relative pigmentation (Fig. 6). 4. Arbutin This skin whitening study involved formulations with arbutin and the hydroxyl terminated 800 polyester, TL- 8. The control formula contained 10% arbutin without polyester, while the test formulation contained 2.5% TL-8 polyester and only 5% arbutin. Test products were applied to panelists' forearms twice daily for 28 days, and were observed for relative pigmentation weekly (Fig.7). Results Figure 1. Comparison of 5000 MW Polyesters with Organic Sunscreens via Tape Stripping ,J l 5 ß aoo I I []Oxybenzone I •, • • IDEG-C5.0: AdipicAcid/Diethylene Glycol/Coconut • 80 • HFattyAcid Copolymer I • • • • lJ DEo-5.0:AdipicAcid/Diethyleneolycølcøpølymer •) 60• • • • • r]_DEO_X5.0: Adipic Acid/Diethylene Olycol/Olyceri n a:: 40• • • • • I-• Crøsspølymer -• I/ / I/ I/ I/ I/ I FMPD-X5'0: Adip ic O• 20• • • • • ]-]Acid/Trim ethylpentanediol/Glycerin Crosspolymer NPG-X5.0: Adipic Acid/Neop•ntyt Glycol/Glycerin • 0 rosspolymer Control DEG-5.0 DEG- NPG- TMPD- DEG- C5.0 X5.0 X5.0 X5.0 Figure 2. Effect of Polyester upon the Mosquito Repellent Properties of DEET Over 6 Hours 400 350 • 250 200 100 50 :8•

348 JOURNAL OF COSMETIC SCIENCE Figure 3. Effect of Polyesters on the Cell Renewal Rate of AHA Formulations (10% undissociated Lactic Acid) via Comparative Cytology eN 12 • 10 (,.) 8 ._c: 6• • 4• e• 2-- c• 0 '• -2 [] Polyester TL-8 ß Polyester TC-8 ß Control Day 7 Day 14 Day 21 Day 28 Figure 4. Effect of 10% Undissociated Lactic Acid Skin Whitening with TL-8 Polyester t.5 t.I) .... I).5 0.0 0 7 14 21 28 42 Days -'e--Control with 5% TL-8 --•'-with 2.5% TL-8 Figure 5. Effect of Polyesters TL-8 and TC-8 on Skin Whitening Effect of 2% Hydroquinone 3.0 '1.5 0.5 0.0 I 7 14 21 28 '"e"'CONTROL with 5% TL-8 '-•"with 5% TC-8 DAY