This article reviews the work on the technique for preparing a variety of liquid/liquid type multiple-phase dispersions. The major contents are divided into three sections: principle for obtaining multi-lamellar and single compartment lipomes, two-step procedure for emulsification in preparing the water-in-oil-in-water (W/O/W) type multiple-phase emulsions by use of liquid paraffine and ordinary emulsifying agents, and application of the two-step procedure for providing liposome-like lipid vesicle suspensions composed of the mixture of purified soy lecithin and Span 80.

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The transepidermal water loss (TWL) was measured on healthy adults using the electrohygrometric method.
TWL value was significantly higher in 20-24 ages than in 25-50 ages. The relationship between TWL value and ambient conditions seemed to vary exponentially. The occlusive nature of petrolatum decreased with raising temperature and relative humidity.
These results showed availabilities of our original method for TWL in cosmetological research.

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Melanins are widely distributed in the animal and vegetable kingdoms, and are insoluble polymeric pigment which contributes mainly to the color of our skin and hair. In this study, various conditions of hydrolysis with hydrochloric acid were examined in details to extract melanin effectively from human hair with least modifcation. As a result, HCl-refluxing for 24 hours was found to be the most desirable method for the extraction of melanin having almost constant C/N ratio and absorption at 400nm. Various solvents were also investigated to solubilize the extracted melanin and solution of dimethyl n-undecyl n-dodecyl ammonium hydroxide in toluene (“Soluene 100”) and aqueous solution of tetramethyl ammonium hydroxide were found to satisfy the requirement. This made it possible to detrmine the melain contents in hair samples bleached in various degrees by using colorimetry.

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Some evaluation methods about emulsifying properties of surfactants in combination with typical oils used in cosmetics, cloud point in oil saturation, phase inversion temperature, emulsifying power and emulsion stability are mentioned,
The combination effect of representative surfactants with oils in emulsifying properties is discussed by each evaluation method. Especially the branching alkyl chain of surfactant is on interesting behavior.

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Instead of relying on the usual, long-range shelf-test for determining emulsion stability, a technique utilizing the light scattering property of emulsions was developed to allow the determination within a short period of time.
In the previous report (Part 1), the oil phase was restricted to mineral oil and the concentration of the oil phase was kept constant in determining the effects of surfactant type and surfactant concentration on the stability index. It was found that the stable region was below stability index, R=0.33 and the unstable region was above R=0.46 Between these two R values, the stability was ambiguous.
In this report, four different oils, including a higher alcohol (hexadecyl alcohol), ester (isopropylmyristate), triglyceride (castor oil) and four different surfactants were studied at varying oil phase concentrations to determine the effects on stability indices.
The experimental data indicated that for isopropylmyristate, the stable region was below R=0.157 and the unstable region was above R=0.203. The stability was ambiguous between these two values. For hexadecyl alcohol, the stable region was below R=0.163 and the unstable region was above 0.211. For castor oil, the stable region was below R=0.177 and the unstable region was above 0.22. The values for the lanolin system were 0.209 and 0.251 respectively.
It is clear that the boundaries for the stable and unstable regions varied somewhat depending on the type of oils employed. The reason for the variation will be clarified in the future research work.

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The antimicrobial activity of preservatives incorprated in oil-in-water emulsion systems has been stated to be controlled by the concentration of the undissociated free species in the aqueous phase. An ultrafiltration technique using Diaflo membrane was investigated in order to measure the free methyl-p-hydroxybenzoate (MP) in the aqueous phase of the oil-in-water emulsion. Free MP in the aqueous phase were separated from emulsions containing various amounts of MP and analyzed quantiatively. Free MP concentration in the aqueous phase from the ultrafiltration method coincided well with the results from the antimicrobial activity in the miorobiological method.
But, the ratio between free MP concentration in the aqueous phase and total MP concentration did not hold constant but depended upon total MP concentration.
Thus, the interaction of MP with polyoxyethylene lauryl ethers having a various number of oxyethylene unit was investigated by ultrafiltration and also nuclear magnetic resonance spectrometry. The results obtained suggested the existence of two kinds of interaction mechanisms between MP and the nonionic emulsifier micelle. The binding parameters in the each class were calculated using a multiple regression technique. In the primary class of sites, the interaction obeyed the form of the Langmuir type adsorption and the bound molecules of MP were probably located at the interface of the hydrocarbon core and the polyoxyethylene mantle of the micelle. Moreover, in the second class of sites, the interaction could be described as a simple partition between the micelles and the aquous phase and the preservative molecules seemed to be situated in the polyoxyethylene mantle.
Using these results, the theoretical equation including the interaction of MP and nonionic emulsifier micelles in oil-in-water emulsion. Free MP concentration in the aquous phase of emulsions containing various amounts of MP were calculated from this equation. The results calculated were in good agreement with those obtained from the ultrafiltration method.

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The microbiological quality of a variety of cosmetics, collected in Osaka Prefecture from 1972 to 1977, has been investigated.
By this surveys, about 15% of 657 samples of unused cosmetics were found to be contaminated with bacteria and fungi.
The most frequently contaminations in cosmetic products, were found in facial or hand creams (34% of 152 samples), liquid creams (21% of 42 samples), liquid shampoos (18% of samples) and hair lotions (15% of 46 samples), whereas we have rarely detected microbiological contamination less than 10% of the samples (which include hair sprays, hair tonics and facial or hand lotions).
In these majority of cosmetic products contaminated with microorganisms, gram-possitive or gram-negative bacteria (which includes Bacillus, Micrococcus, and the like) and mold were mainly found as the lower microbiological counts (which not mostly exceed 1000 per gram or ml). But some specific bacteria (St. aureus, Ps. aeruginosa, E. coli and Coli-forms organisms) were not isolated from such contaminated cosmetics.
In the view of these results, it is obvious that the total counts (in a low microbiological load) can be excellent index of micro-biological quality.

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