Though various kinetic theories for analyzing detergency such as those based on first order reaction formulas have been published, a new method called probability density functional method is currently being developed. This expresses the detergency by two parameters, the standard deviation and the average value of the detergency distribution, under the assumption that both the adhesion force of dirt and the removal force follow a normal distribution. Previous studies have shown that it is possible to predict the cleaning efficiency by associating the cleaning power with the cleaning rate. It was also found that the parameter σ_rl is related to the cleaning mechanism and can be used to estimate it. As for the other parameter µ_rl which is directly related to the detergency, Δµ_rl which is the difference between µ_rl values obtained under different cleaning condition can be used to determine interaction between the two cleaning elements whether it is an additive effect, a synergistic effect, or an offset effect. This method may become a promising analysis tool in a wide range of applications including cleaning fields.

The advantages of infrared and Raman spectroscopy are that they are non-destructive, requires no sample extraction or purification, and directly provide structural information of lipids, fatty acids, proteins etc. In particular, by using attenuated total reflection (ATR)-FT/IR, which is suitable to for surface characterization, oil- and protein-based soil components attached to the same surface of a wet-type artificially soiled fabric can be directly and separately quantified at the same time. In this article, a novel spectroscopic method for quantitative evaluation of detergency using the ATR-FT/IR method is reviewed with introducing some characterization results.

Cleansing agents such as facial cleansers and makeup removers are required not only to have high cleansing power against excess sebum and makeup, but also to be particularly gentle to the skin and hypoallergenic since they are used on the face.

Therefore, we are focusing on polyglycerol fatty acid esters (PGFEs), which is highly safe and widely used in leave-on type skin care products, and investigating its skin care effects when used as a cleansing ingredient.The results of various evaluations showed that cleaning formulations containing PGFEs didn’t disrupt skin barrier functions such as intercellular lipids, and were effective in suppressing multiple exfoliation of stratum corneum, reducing the size of keratotic plugs and carbonylation level of stratum corneum around skin pores. This article introduces the skin care effects required of cleaning agents in terms of the water-holding capacity of PGFEs and its adsorption behavior on stratum corneum.

Controlling oxidative stress on the skin surface, such as lipid peroxidation in sebum and subsequent carbonylation of stratum corneum proteins, is an important challenge in the field of cosmetology because this stress negatively affects the properties and appearance of the skin. Sebum spreads through the pores in skin to the surface of the stratum corneum, so the oxidation of sebum as a phenomenon that occurs within the pores cannot be overlooked. Therefore, to control oxidative stress on the skin surface, it is necessary to understand it as a series of oxidative stress reactions of the sebum, stratum corneum, pores, and pore plugs. This article presents the effects of pore plugs to oxidative stress for skin and the contribution reducing oxidative stress via pore plug cleansing has on skin color.

Keeping the oral environment hygienic is effective in the prevention of oral diseases such as dental caries and periodontal disease, and is thought to be related to improving oral-related quality of life. Therefore, it is important to remove stains by daily tooth brushing as a way to maintain healthy oral environment. In this study, we focused on sodium pyrophosphate (PPNa) which is known to remove stains and is used in commercial toothpastes, to clarify the stain removal mechanism. The results showed that the thickness of the stain composed of proteins and polyphenols increased by applying PPNa to the stain on the tooth surface model. In addition, the particle size of the aggregates of the stain was reduced. These results suggested that the chelating effect of PPNa trapped Ca in the aggregates and decomposed them. It was also inferred that the increase in thickness of the stain made it easier to be removed by physical force. Furthermore, we examined the combined effect with a surfactant (sodium lauryl sulfate) and found that the stain removal effect was synergistically improved.