Shampoos are susceptible to microbial contamination because anionic surfactants, basic ingredients in shampoos, have low antimicrobial activity against gram negative bacteria. Contamination of these microbes, especially Pseudomonads, in commercial shampoos has been reported on occasion. On the other hand, microbes which can grow in hair rinses are limited because cationic surfactants, basic ingredients in hair rinses, have comparatively high antimicrobial activity. Bodysoaps also have high preservation activity due to the antimicrobial activity of fatty acid salts.
These products are generally used in bathroom, therefore attention should be payed to microbial invasion from the environments during consumer use. In order to preserve these products, it is necessary to consider inherent self-preservation activity of base components and to use suitable preservatives. It is also important to understand the characteristics of each preservatives and to formulate them effectively when selecting a preservative system.
In addition, good manufacturing practice is necessary for prevention of microbial contamination during manufacture. Effective microbial control can be conducted by adequate treatment of row materials, careful attention to hygienic processing and well designed sanitary facilities.

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Surfactants form various self-organizing structures in solution. The relationship between formation of self-organizing structures, especially, microemulsions, high-internal-phase-ratio-emulsions (HIPREs), and reverse vesicles and the phase behavior in water/nonionic surfactant/oil system is reviewed.
Ultra-low interfacial tensions and maximum solubilization are attained in microemulsion systems when the HLB (Hydrophile-Lipophile Balance) of surfactant is optimum in a given systems These properties are used for practical applications such as enhanced oil recovery, detergency, etc.
The new method to form HIPRE is discussed, In this method, O/W microemulsions are spontaneously changed to HIPRE by changing temperature. Finally, we describe the recent result of reverse vesicles.

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In spite of the popularity of cosmetics, many users are unhappy with “artificial look” created by commercial makeups. Our investigation reveals that goniometric optical properties of the skin are very important in determining the appearance of the skin; whether it is regarded beautiful, not beautiful or artificially beautiful. Specifically, the value of the spectral ratio, that is, the spectral reflectance Ratio of Acute incident angle/acute reflection angle to Obtuse incident angle/obtuse reflection angle (RAO) was found to be a key parameter in determining the differences. RAO is the spectral ratio measured when the light incidence angle and receiving angle are nearly parallel to the surface and when the angles are nearly vertical to the surface. Maximum RAO of bare skin ranges from 2.5 to 14.0, but only when the value is between 4.3 and 6.5, the skin appears beautiful. Application of makeups on bare skin lowers the value from 0.8 to 3.0 range, creating “artificial” look.
Furthermore, the semi-transparent nature of stratum corneum was found important in contributing to the “natural look” of the bare skin. To develop natural-look makeups, we prepared several novel complex pigments, consisting of plate-like, high refractive-index (1.9 to 2.6) pigments covered with a low refractive-index (1.3 to 1.6) substance. Using these optically-modified complex pigments, we formulated a series of unique makeups, named “Optically Simulated Dermal (OSD) Makeups”. Panel tests confirmed that OSD makeups allowed the users to look far more natural and less artificial than conventional makeups. Optical measurements also confirmed the increased RAO values when the subjects used OSD makeups instead of conventional makeups. In addition to makeup applications, the novel complex pigments without color were found very useful as an additive in the skin creams to improve the appearance of the skin.

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Polyglycerin fatty acid esters (PGE) were studied as possible dispersants for micronized titanium dioxides in oils with different polarities. The interfacial tension between water and oil containing the micronized titanium dioxides remained constant within a certain concentration range of dispersant but decreased sharply thereafter. The concentration at which the interfacial tension decreased corresponded to that of the dispersant, which dispersed the micronized titanium dioxides in the oils homogeneously. The dispersions of the titanium dioxides in oils were observed by microscope.
We found that hexaglyceryl polyricinolate was effective in dispersing the micronized titanium dioxides in a medium chain triglyceride while decaglyceryl pentaisostearate was effective in dispersing the micronized titanium dioxides in mineral oil.

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In order to achieve the objective of preparing titanium dioxide with a homogeneous dispersibility both in the system when formulating cosmetics and in the cosmetics film when applying cosmetics, we attempted to prepare hollow porous titanium dioxide spheres with controlled collapsibility (HPTC), and examined its properties.
It was found that HPTC was prepared to remove the starch spheres and to sinter the titanium dioxide by heating titanium dioxide coated starch, which is prepared by the attachment and agglomeration of microfine titanium dioxide on the surface of the starch spheres as the core material. In order to keep HPTC shape, the method of preparation of it, was done by heating it at lower temperatures; and the collapsibility of it could be controlled by heating it at certain high temperature.
It was found that HPTC could be well dispersed in the cream by simple mixing, and the cream containing HPTC could opaque ultraviolet light effectively because microfine titanium dioxide was homogeneously dispersed by the collapse of HPTC in the film when it was applied.

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In order to examine the participation of calcium in contact sensitization pathways, sensitizing tests and human patch test were conducted by means of cutaneous administration of chelating agents with several allergens.
Experiments were conducted by adjuvant patch tests in guinea pigs, using ethylenediaminetetra acetic acid (EDTA) as the chelating agents and paraphenylenediamine (PPD) as the sensitizing agent. Groups for PPD only sensitization, mixture of PPD and EDTA sensitization, EDTA only sensitization and vehicle as a control were established, then these materials administered on individual animals for eliciting. In this way the influence of EDTA administration on induction and on allergic inflammatory responses was examined.
As a result, in the 1.0% PPD induction group, both the sensitizing factor and eliciting responses did not show variation from the values of the control groups; but in the case of 0.1% PPD induction goups, both sensitizing factor and eliciting responses showed a decrease with the cutaneous administration of EDTA. Therefore it is thought that EDTA was operating in an anti-inflammatory and/or sensitizing controlling capacity.
In addition 48-hour patch tests using 1-carvone and some chelating agents were conducted on a human subject with allergic contact dermatitis to 1-carvone. In these results as well, decreased skin responses in cases with chelating agents were noted.
From these results we report interesting information regarding the relationship between calcium and the mechanism of Type IV allergy and the anti-allergic property of chelating agents.

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The conductometric determination method (CDM) has been used extensively to determine the oxidative deterioration of fats and oils. We applied the CDM to study the catalytic activity of inorganic pigments for oilcontaining cosmetics. Using the pigments and oleic acid mixtures as CDM samples, the times taken to increase of 100μScm^-1 in electrical conductivity, corresponded to the amount of oxidized products, were determined at 70°C and 20Lhr^-1 air flow. Alumina, clay minerals, and iron oxides were found to promote the oxidation of the fatty acid. Moreover, the blocking effect of silica coating on the catalytic activity of iron oxides was confirmed using the CDM. These results demonstrated the usefulness of the CDM for the determination of the catalytic activity of pigments used for cosmetics.

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