PREPRINTS OF THE 1996 ANNUAL SCIENTIFIC MEETING 293 In the mid 1980s enhanced efficacy (activated) aluminum-zirconium-glycine actives were introduced. Activated AZG powders were also enriched in AI Kdo. 4 (4-6). Thus it was assumed that activated AZG containing large amounts of AI Kdo. 4 should outperform standard (normal) AZG, which contains little AI Kdo. 4. Surprisingly, many so-called activated AZG salts were no better than standard AZG salts and in fact could show inferior performance compared to standard AZG actives. This anomoly becomes clear when one considers the effect of zirconium chemistry on efficacy, which until now has not been addressed. CHARACTERIZATION OF ZIRCONIUM POLYMER DISTRIBUTIONS Using Sephacryl columns in conjunction with ICP techniques to measure Zr, Rosenberg et al. (7) were able to determine Zr polymer distributions present in AZG actives. Thus, changes in Zr polymer distribution as a function of synthesis and processing could be determined and then correlated to clinical efficacy results. A striking example of how Zr polymer distribution affects clinical efficacy is seen in Figure 2, which shows Zr polymer distributions for a so-called activated tetra AZG powder containing large amounts of AI Kdo.4, and for a standard tetra AZG powder containing small amounts of AI Kdo. 4. Clinical results comparing these materials showed that the standard AZG active out- performed the so-called activated AZG (statistically significant result). This result is surprising only if one solely considers AI polymer distributions. However, the larger molecular weight Zr polymer distribution of the so-called activated AZG compared to the standard AZG negatively impacted the efficacy of the activated AZG even though it contained large amounts of the AI Kdo. 4 polymer. Other correlations of Zr polymer distributions versus clinical efficacy confirm that Zr polymer distributions are more important than AI Kdo. 4 enrichment, with lower molecular weight Zr polymer distri- butions being more desirable with respect to enhanced efficacy (7). FACTORS AFFECTING ZR POLYMER DISTRIBUTIONS Since Zr polymer distribution strongly impacts efficacy, it is important to understand how synthesis and processing affect the resultant Zr polymer distribution of the finished AZG product. Some important factors to consider are the nature of the Zr starting materials: heat, addition of glycine, and contact time of the AI and Zr components before spray drying. This approach to manufacturing enhanced efficacy AZG actives is • m NOFU4,q,L A7.G • m m m m m A•TIYAT•D•T O m • O a i/ -..% EL•ION TIME Figure 2. Zirconium polymer distributions for a normal (standard) and a so-called activated AZG.

294 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS ELUTION TIME Figure 3. Zirconium polymer distributions for standard (AZG-370) and enhanced efficacy (AZG-375) actives. quite different from preparing AZG materials with large amounts of A1 Kdo.4, but with no concern about Zr chemistry. A practical consequence of the above has been the development of a novel enhanced efficacy tetra AZG powder that contains little A1 Kdo.4, but with careful control of the Zr polymer distribution. Figure 3 shows the Zr polymer distribution of this material (AZG-375) versus that for a standard tetra AZG active (AZG-370) prepared by con- ventional techniques. The lower-molecular-weight Zr polymer distribution for AZG- 375 is the key factor in providing enhanced efficacy. REFERENCES (1) Fitzgerald, Phipps et al., UK Patent Application 2,048,229A (1980). (2) Gosling et al., US Patent 4,359,456 (1982). (3) Markarian and Rosenberg, US Patent 4,818,512 (1989). (4) Callaghan and Phipps, US Patent 4,775,528 (1988). (5) Giovanniello and Howe, US Patent 4,871,515 (1989). (6) Callaghan and Phipps, US Patent 5,298,640 (1994). (7) Rosenberg et al., European Patent Application 0 653 203 A1 (1995). Applications of polyglycerin fatty acid esters to skin care cosmetics JUNICHI NAKAMURA, KAZUHIKO TAKAHASHI, and MASATO TAGAWA, Nikko Chemicals Co., Ltd., Cosmos R&D, Itabashi-ku, Tokyo 174, Japan. INTRODUCTION We have developed polyglycerin fatty acid esters with different functions for skin care