Papers Presented at the Annual Scientific Seminar of the Society of Cosmetic Chemists (Friday's Program)

410 JOURNAL OF COSMETIC SCIENCE ysv Figure l. The Equilibrium Contact Angle Figure 3. Coulombic Interactions Figure S. Wetting of IS nm. Ti02 Dispersed in Cyclopentasiloxane TIO,CR-137 2110,000�----------- 1SO,OOO 100,000 51,000 .LO_ Untrnwd MS ITT ::·a:,�::. &Hane !' :,:-,:,.:);.::yfR!o:' Figure 7. 75% Pre-mixes in Cl2-15 Alkyl Benzoate with Polyhydroxystearic acid as Dispersant. (a) (b) Figure 2. Steric Interactions lntarpartlc 11i.t• Dlalan"" (nml 0 10 20 30 40 118 �· ···�0 r Vi!.4 1 · 0 ParticleDlame18r(llftl) o(t•f5• t::. -20 Figure 4. Forces of Attractive Energy 7$% In Mineral OH 13% In Cyclo.,.ntullouno GP8 1,soo,000�,.....�-------, cl'9 1,500,000 ......,,--,----------, Toolhlck 14- Toclllidl tomeuun 1,000,000 • ..... ........... ······••·•··•· .••.••••. .,......... 1,000,000 .. ··••· ....•. ······•··•············· .. ·•········•·· IOO,GDO ·• Untreated ITT :TT:'TCS SIiano t M¥'!)J»'YM�f Untruted I T T :r:r.c.s SIi.ina ,:-....o.p:i}'rt,O Figure 6. Treated Iron Oxides Pre-mixes with Silicone/Copolymer Dispersant eltck '"'" Oxla C3Mfllll 400.ooo�---------, 300,000 21IO,OOO 100,000. 48,400 cl'a Untreated 1% all1ne 2% ollono TIO,CR-837 cPa 200.000-r--==--------, 150,000 ·•···· ··············'"·········· ·'···· ········ 100.000 ···•················ ..................... . 50,000 Figure 8. Acqueous Pre-mixes of Polyether-Si lane Treated Pigments

2004 ANNUAL SCIENTIFIC SEMINAR 411 .,,. T10 1 CM:.U7 , ...............--.------------, toe,OOG ·•• UntnatldMI SllaM 2� m TT1I TTI Figure 9. 75% Branched Dimethicone Treated TiO, in Cyclopentasiloxane with a Silicone/Copolymer Dispersant Dispersion Percent P.S. VIKoslly lndonlof P.P.S, (NII) Type P,S, lndaof ro-.ilat1C1 §ol .. ,....., tl'l) Aglo,_,_n -1 ,...._......, tsodoc1«""" a 60% 1n 180 P0l)'hyllr�1•UN1tlc acid lod1dcane a 110' 10 i'allflYlrOrytle!lr1t e.id C 11-" Alkyl &enZOf� 8- � 165 600 : �olyt,ydroxvste•rk acid C�talll onc& -4CS 16! 275 j r£G· 10 OlrrctlliCOM ............... \�3 7.9 1U !1.8 I (·--· 20 2Q·30 120 no, rte, lnO lnO 110 11 143 9.5 !43 ·t 7.2 145 �-11 !79 5.1 250 1.) Table I. Influence of Carrier and Dispersant on Dispenion of 14 run. Methicone Treated TiO, Table 2. Influence of Particle Size on Agglomeration Refereiu;es 1. Al Home, DS Johnson, JA Kilgour, RD Wang (General Electtic Company), US Patent 5,998,542 (1999). 2. JM Gardlik, GJ Guskey, B Curtis (Procter & Gamble), US Patent 6,171,601 (2001). 3. RBK Ha, TJ Fowler (Procter & Gamble), US Patent 5,997,887 (1999). 4. ER Lukenbach, C Cole, P Naik-Satam, R Stutzman (Johnson and Johnson Consumer Products, Inc), US Patent 6,540,986 (2003). 5. MR Neam, SJ Redshaw, G Burgess, Titanimn Dioxide Based Sunscreen Compositions, US Patent 5,498,406, (1996). 6. I Walele, SA Syed,(Finetex, Inc.) US Patent 6,261,713 (2000). 7. C Corcoran, J Zecchino, S Mesin, K Chung (Estee Lauder, Inc.), US Patent 5,468,471, 1994. 8. JM Oyarzun, Pigment Processing, Physico-chemicalPrinciples: 4, 2000. pp 117-166. 9. DH Solomon and DG Hawthorne, Chemistry of Pigments and Fillers: 2, 51-57, 1991 10. D Schlossman and Y Shao (Kobo Products, Inc.), Silicone Dispersants and Physical Sunscreen Dispersions, Recent Developments, SCC Florida Chapter Sun Screen Symposium September 12, 2003. 11. D Schlossman and Y Shao (Kobo Products, Inc.), Super Dispersible Pigments for Color Cosmetics, Color Cosmetics Summit 2003, Montreal, Quebec, October 20-22, 2003. 12. D Schlossman and Y Shao (Kobo Products, Inc.), Silicone Dispersants and Physical Sunscreen Dispersions, Recent Developments, The European Sunfilters Conference -Paris October 14-15, 2003. 13. H Ono, T Matsui, I Miyamoto (Asahi Kasei KK), US Patent 6,541,627 (2003) 14. RA Williams, FJ Dickin (Disperse Technologies Lmited), US Patent 6,210,972 (2001).

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410 JOURNAL OF COSMETIC SCIENCE ysv Figure l. The Equilibrium Contact Angle Figure 3. Coulombic Interactions Figure S. Wetting of IS nm. Ti02 Dispersed in Cyclopentasiloxane TIO,CR-137 2110,000�----------- 1SO,OOO 100,000 51,000 .LO_ Untrnwd MS ITT ::·a:,�::. &Hane !' :,:-,:,.:);.::yfR!o:' Figure 7. 75% Pre-mixes in Cl2-15 Alkyl Benzoate with Polyhydroxystearic acid as Dispersant. (a) (b) Figure 2. Steric Interactions lntarpartlc 11i.t• Dlalan"" (nml 0 10 20 30 40 118 �· ···�0 r Vi!.4 1 · 0 ParticleDlame18r(llftl) o(t•f5• t::. -20 Figure 4. Forces of Attractive Energy 7$% In Mineral OH 13% In Cyclo.,.ntullouno GP8 1,soo,000�,.....�-------, cl'9 1,500,000 ......,,--,----------, Toolhlck 14- Toclllidl tomeuun 1,000,000 • ..... ........... ······••·•··•· .••.••••. .,......... 1,000,000 .. ··••· ....•. ······•··•············· .. ·•········•·· IOO,GDO ·• Untreated ITT :TT:'TCS SIiano t M¥'!)J»'YM�f Untruted I T T :r:r.c.s SIi.ina ,:-....o.p:i}'rt,O Figure 6. Treated Iron Oxides Pre-mixes with Silicone/Copolymer Dispersant eltck '"'" Oxla C3Mfllll 400.ooo�---------, 300,000 21IO,OOO 100,000. 48,400 cl'a Untreated 1% all1ne 2% ollono TIO,CR-837 cPa 200.000-r--==--------, 150,000 ·•···· ··············'"·········· ·'···· ········ 100.000 ···•················ ..................... . 50,000 Figure 8. Acqueous Pre-mixes of Polyether-Si lane Treated Pigments

2004 ANNUAL SCIENTIFIC SEMINAR 411 .,,. T10 1 CM:.U7 , ...............--.------------, toe,OOG ·•• UntnatldMI SllaM 2� m TT1I TTI Figure 9. 75% Branched Dimethicone Treated TiO, in Cyclopentasiloxane with a Silicone/Copolymer Dispersant Dispersion Percent P.S. VIKoslly lndonlof P.P.S, (NII) Type P,S, lndaof ro-.ilat1C1 §ol .. ,....., tl'l) Aglo,_,_n -1 ,...._......, tsodoc1«""" a 60% 1n 180 P0l)'hyllr�1•UN1tlc acid lod1dcane a 110' 10 i'allflYlrOrytle!lr1t e.id C 11-" Alkyl &enZOf� 8- � 165 600 : �olyt,ydroxvste•rk acid C�talll onc& -4CS 16! 275 j r£G· 10 OlrrctlliCOM ............... \�3 7.9 1U !1.8 I (·--· 20 2Q·30 120 no, rte, lnO lnO 110 11 143 9.5 !43 ·t 7.2 145 �-11 !79 5.1 250 1.) Table I. Influence of Carrier and Dispersant on Dispenion of 14 run. Methicone Treated TiO, Table 2. Influence of Particle Size on Agglomeration Refereiu;es 1. Al Home, DS Johnson, JA Kilgour, RD Wang (General Electtic Company), US Patent 5,998,542 (1999). 2. JM Gardlik, GJ Guskey, B Curtis (Procter & Gamble), US Patent 6,171,601 (2001). 3. RBK Ha, TJ Fowler (Procter & Gamble), US Patent 5,997,887 (1999). 4. ER Lukenbach, C Cole, P Naik-Satam, R Stutzman (Johnson and Johnson Consumer Products, Inc), US Patent 6,540,986 (2003). 5. MR Neam, SJ Redshaw, G Burgess, Titanimn Dioxide Based Sunscreen Compositions, US Patent 5,498,406, (1996). 6. I Walele, SA Syed,(Finetex, Inc.) US Patent 6,261,713 (2000). 7. C Corcoran, J Zecchino, S Mesin, K Chung (Estee Lauder, Inc.), US Patent 5,468,471, 1994. 8. JM Oyarzun, Pigment Processing, Physico-chemicalPrinciples: 4, 2000. pp 117-166. 9. DH Solomon and DG Hawthorne, Chemistry of Pigments and Fillers: 2, 51-57, 1991 10. D Schlossman and Y Shao (Kobo Products, Inc.), Silicone Dispersants and Physical Sunscreen Dispersions, Recent Developments, SCC Florida Chapter Sun Screen Symposium September 12, 2003. 11. D Schlossman and Y Shao (Kobo Products, Inc.), Super Dispersible Pigments for Color Cosmetics, Color Cosmetics Summit 2003, Montreal, Quebec, October 20-22, 2003. 12. D Schlossman and Y Shao (Kobo Products, Inc.), Silicone Dispersants and Physical Sunscreen Dispersions, Recent Developments, The European Sunfilters Conference -Paris October 14-15, 2003. 13. H Ono, T Matsui, I Miyamoto (Asahi Kasei KK), US Patent 6,541,627 (2003) 14. RA Williams, FJ Dickin (Disperse Technologies Lmited), US Patent 6,210,972 (2001).

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408 JOURNAL OF COSMETIC SCIENCE DISPERSION OF PARTICULATES David Schlossman and Yun Shao, Ph.D. Kobo Products, Inc., South Plainfield, NJ Introduction The popularity of personal care formulations containing particulates with consumers depends on sensory characteristics such as their color, gloss, wear, wrinkle hiding power, transparency, softness, spreadability, blendability, and smoothness, in addition to stability in the finished product. Thus, dispersions of particulates are important to cosmetic chemists, because the desirable properties of the particulates are likely to be influenced by the degree of their dispersion in the formulation. Terms such as dispersions, slum.es, grinds, pastes, suspensions and gels are all used by cosmetic chemists to describe mixing particles in a liquid medium. The elements of particulate dispersion technology, wetting, stabilizing, and grinding are frequently cited in patents. Home, et al. claimed a novel silicone elastomer gel processed from the flow induced shearing through an orifice of a cross linked particulate to create a unique multiple particle size distribution with improved spreadability and substance (I). Gardlik, et al. patented a low residue antiperspirant gel-solid stick comprised of a particulate dispersion of antiperspirant actives held within a non-polymeric crystalline gel-solid matrix (2). Skin care compositions to improve skin appearance containing a charged particulate material dispersed in a thickened hydrophilic carrier were disclosed by Ha, et al. (3) Numerous references can be found describing methods to disperse and emulsify inorganic ultraviolet filters to enhance their SPF and efficacy in formulations (4,5,6,7). Dispersions of particulates have been extensively studied and numerous mathematical models have been proposed to describe their behavior. In practice, however, the formulation and testing of a particulate dispersion is still considered to be much of an art. In this presentation, both science and art will be acknowledged. Princiules of Disnersions Volumes of articles, chapters and textbooks have been published on the science of dispersions. Dispersion is a stepwise process. The objective is to produce in an application medium a stable and uniform milling of finely-divided particles, i.e. aggregates and primary particles. Mechanical Breakdown In order to achieve mechanical breakdown it is necessary to use energy to break down the cohesive forces, the intermolecular forces of attraction that hold the solid particles together. The primary particles always aggregate to form secondary particles due to their high surface energy such as Van der Waal's forces, electrostatic force, hydrogen bonding of surface hydroxyl groups and water bridging between the primary particles (8) The hardness and morphology of the particulate, its percent solids in the carrier and the viscosity of the pre-mix are all likely to influence the mechanical process. High pressure homogenizers, sonolators, and bead mills are all well suited to disperse particulates. Wetting The oil absorption value of a particulate will give an indication about its wetting. Theoretically, the wetting of a solid by a liquid is often described in tenns of the equilibrium contact angle formed at the solid-liquid-vapor (air) triple interface or the spreading coefficient. Both are functions of the three paired interfaces as shown in Figure l. The maximum wetting occurs when the contact angle is zero or when the spreading coefficient has a large positive value (9). Besides surface treatment, dispersing aids are frequently added to increase wetting and stabilization. They also reduce the amount of mixing and milling time, which may prevent the over milling and fracturing of the particles. The finesses of the pigment grind will be detennined by the wetting of the particles in the carrier. (9). Stabilization Unless the particulates are immobilized by the high viscosity of the slurry, after the mechanical forces that accompany the dispersion process are removed, the forces between the particles will start to come into effect that will lead to sedimentation and flocculation or stabilization. The close approach of particles can be repelled by Coulombic interactions between similarly charged particles in polar media or through steric interactions between long-chain molecules adsorbed on the particulate surfaces. These interactions are shown as Figures 2 and 3, respectively. Steric stabilization can operate in both aqueous and non-aqueous media (9). The ideal stabilizing molecule must be capable of being absorbed on the particles surface (and swollen around each particle) and being solvated and extended into the carrier. Particles possess potential attractive and repulsive energies whose actions are strongly determined by their distance of separation. As the distance between particles is increased the interaction energy is

2004 ANNUAL SCIENTIFIC SEMINAR 409 diminished. The attractive energy arises from Van der Waal's forces. Thus, the thickness of the adsorbed layer necessary for the effective stabilization of the dispersed particles increases with increasing particle sizes as shown in Figure 4 (8,9). According to theoretical calculations, dispersions of micronized pigments with particle sizes under 0.2 microns should require a thinner layer than dispersions of pigmentary grades or other filler particles greater than 1 micron. Apnlications of Dispersion Technologv In practice, most of the inorganic particulates contained in cosmetic formulations have highly polar surfaces that are hydrophilic, and are poorly wetted by organic carriers with low to medium polarity such as cyclopentasiloxanes, hydrocarbons and esters. Organic surface treatments like alkoxy titanates, silanes, methyl polysiloxanes, and alkoxy dimethicones are all known to react with and displace the air and water of hydration absorbed on a pigment surface, rendering it from hydrophilic to hydrophobic or lipophilic. We compared the importance of the surface treatment to the dispersant to pre-wet a 15 nanometer micronized titanium in cyclopentasiloxane in Figure 5. (10) Further, we developed a novel crosspolymer surface treatment to promote the wetting of pigments in multimedia. Fi gu re 6 shows the viscosity of treated iron oxide pre-mixes in mineral oil and cyclopentasiloxane. Fi gu re 7 shows the viscosity of a treated rutile titanium dioxide pre-mix in an ester. (11). Cosmetic dispersions are also made in hydrous (water, polyhydric alcohol) systems. Ammonium and sodium polyacrylates have been found to be important dispersing aids, acting to swell the particles water layer and put a stabilizing charge on their surface. According to our study, reactive polyether silanes may also be employed to enhance wetting in aqueous systems. Viscosity data for iron oxide and titanium dioxide premixes can be found in Figure 8 (11). Lastly, we compared the wetting of branched dimethicone treated rutile titanium dioxide in cyclopentasiloxane to popular hydrophobic treatments in Figure 9 by measuring their pre-mix viscosities. (11 ). Table I lists the viscosity and particles sizes of four dispersions containing a 14 nn1. methicone treated micro titanium dioxide that we compared (12). The wetting was best when polyhydroxystearic acid was used as the dispersant in isododecane. All the dispersions were stable at 50°C for one week. Experiments were made dispersing inorganic ultraviolet filters with primary particle sizes ranging from 10 to 200 nm. in silicone fluids, hydrocarbons and esters with various surface treatments and dispersants. The dispersion particle sizes were recorded and compared to their primary particle size. An index of agglomeration was calculated as the ratio of the dispersion particle size over the primary particle size (12). The data presented in Table 2 is representative of the samples prepared and shows that pigments having a smaller primary particle size contain larger indices of agglomeration. Thus, smaller primary particles are harder to disperse. We have found that adding bentonite clays, fumed silica, synthetic waxes, and polysaccharides can thicken dispersions to reduce syneresis and improve suspension of pigments and actives. Evaluation of Pigment Dispersions Both science and art play a role in dispersion testing. Twenty-five years ago the plant manager could approve a batch of nail laquer by observing the way it ran off his blade. Nowadays, viscosity samples are mixed with a mechanical mixer and incubated before testing on an instrument such as a Brookfield RVT. Draw downs are still compared by operators at various stages during processing on cards or glass plates to study transparency, color, drying time and gloss, however, greater reliance is placed on instrun1ents. An example is the particle size which is often measured by using a light scattering size analyzer. Nevertheless, it is an art to measure the size correctly, as the powder or dispersion san1ple must be diluted and sonicated to a usually low concentration in an appropriate solvent. Imaging technologies will play a greater role in evaluating dispersions in the future. Ono, et al measured particle sizes of novel dispersions of cellulose particulates with both a light scattering size analyzer and an electron microscope and calculated a coefficient of aggregation of 1.0 to 3.0 (13). Willian1s, et al. patented a microelectrical resistance tomography system comprising one or more sensors to characterize flowing dispersions including particle shape and size. Summarv The conditions to wet pigments were shown to influence their pre-mix viscosity and the dispersion particle size. Silicone/copolymers and polyhydroxystearic acid are effective stabilizers for pigment dispersions. The stability of dispersions could be improved by decreasing their particle size as the theoretical models predict. More work needs to be done to quantify the differences between the dispersions in order to learn more about their behavior and to predict their performance in finished products.

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412 JOURNAL OF COSMETIC SCIENCE A FAMILY OF EMOLLIENT ESTERS EXHIBITS ANTI-MICROBIAL PROPERTIES OF PRACTICAL USE TO FORMULATORS SEEKING TO REDUCE OR ELIMINATE THE USE OF PRESERVATIVES Introduction Monna Manning and Philip Orawski Abitec Corporation, Columbus, OH Kabara and others found that certain fatty acids and esters were useful as antimicrobial agents. 1• 2· 3 Based upon these findings, high purity monoesters of glycerin or propylene glycol were synthesized and assayed for their efficacy against traditional preservatives. Three emollient esters were selected for their anti-microbial properties. This range of high purity short-chain monoglyceride esters have been shown to offer performance comparable to "conventional" anti microbial agents or preservatives, without the need to register as preservatives. Experimental MIC Test and selection of three monoglycerides Eleven (11) structures were evaluated in a Minimum Inhibitory Concentration test (USP 61 "Microbial Limit Tests"), which tests the efficacy of antimicrobial agents versus concentration. Based upon performance in this test, three structures were chosen to pursue as commercially viable products. In all, eleven (11) organisms were used in MIC testing. The following tables indicate the results for four (4) of the most common organisms: Candida albicans ( a yeast), Aspergillus niger (a mold), Staphylococcus aureus (a gram positive bacterium), and Eschirichia. coli (a gram negative bacterium). The legend is"+" to indicate growth, and"-" to indicate microbiological kill. % Dilution 0.010 0.025 0.050 0.075 0.100 0.175 0.250 0.500 0.750 1.000 Candida albicans Propylene Glycol Heptanoat + + + Propylene Glycol Heptanoat + + Glyceryl Caprylate + + + Aspergillus niger Propylene Glycol Heptanoat + + Propylene Glycol Heptanoat + Glyceryl Caprylate + + + + + Staphylococcus aureus Propylene Glycol Heptanoat + + + + + Propylene Glycol Heptanoat + + + Glyceryl Caprylate + + + Escherichia coli Propylene Glycol Heptanoat + + + + + Propylene Glycol Heptanoat + + + + + + + + + + Glyceryl Caprylate + + + + + + + Challenge Test comparison to DMDM Hydantoin and parabens

2004 ANNUAL SCIENTIFIC SEMINAR 413 In a typical TEA Stearate Lotion formulation, three anti-microbial monoglycerides were evaluated in a challenge test (USP 51 "Antimicrobial Effectiveness Testing") against a blend of 0.2% Methylparaben and 0.1 % Propylparaben or against 0.4% DMDM Hydantoin. The individual esters were tested at 0.5%, which is the recommended minimum usage level. E. coli S. aureus A. niger C. albicans Propylene ✓ ✓ ✓ ✓ Glycol Heptanoate Outperformed Outperformed parabens Zero Growth. Outperformed @0.5%in Parabens@ @ 0.3% or DMDM Equal to O .3 % 0.4%DMDM lotion 0.3% Hydantoin@0.4% parabens or DMDM Hydantoin Hydantoin@0.4% Propylene ✓ ✓ Glycol Caprylate Outperformed Outperformed Parabens Performance Performance @0.5%in Parabens@ @0.3% marginally inferior marginally lotion 0.3% inferior Glycerol ✓ ✓ ✓ ✓ Caprylate @0.5 %in lotion Outperformed Outperformed 0.3% Zero Growth. Outperformed 0 .3 % parabens parabens or 0.4% Equal to 0.3% 0.4%DMDM DMDM Hydantoin parabens or O .4% Hydantoin DMDM Hyclantoin Discussion Additional MIC and Challenge test data will be presented and results and implications discussed. References 1. US Pat 4,002,775 Fatty acids and Derivatives of Antimicrobial Agents, Jon Kabara, (January 11, 1977) 2. A Branan and P Davison, Anti-microbials in Foods, Marcel Dekker, ed., New York, ( 1986) pp 109-140 3. J Kabara, and M Ohkawa, et al., Examination on Antitumor, Immunological, and Plant Growth Inhibitory Effects on Monoglycerides of Caprylic Capric and Laurie Acids and Related Compounds Pharmacological Effects of Lipids, Volume II, (1985) pp 263-272

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