Integrating mathematical approaches (IMAS): Novel methodology for predicting dermal absorption rates of chemicals under finite dose conditions.

Quantitative structure permeation relationship (QSPR) models have gained prominence in recent years owing to their capacity to elucidate the influence of physicochemical properties on the dermal absorption of chemicals. These models facilitate the prediction of permeation coefficient (Kp) values, indicating the skin permeability of a chemical under infinite dose conditions. Conversely, obtaining dermal absorption rates (DAs) under finite dose conditions, which are crucial for skin product safety evaluation, remains a challenge when relying solely on Kp predictions from QSPR models.

Sensory irritation to methylparaben is caused by its low metabolism in the skin.

Sensitive skin is a well- known skin condition showing sensory irritation to daily used products such as cosmetics or pharmaceuticals, possibly containing sensory irritants. Methylparaben (MP), widely used as a preservative, is a representative sensory irritant and hydrolyzed in the skin. We aimed to clarify the relationship between MP sensory irritation and MP hydrolysis.

Evaluating the applicability of the Ames test for cosmetic packaging assessment by comparing carcinogenic risk levels of migrants from plastics with biological detection limits.

Risk assessments for cosmetic packaging are required according to the EU Cosmetics Regulation (EC) No. 1223/2009, however, the assessment method is well-established for food packaging but limited for cosmetic packaging. In food packaging assessments, Cramer class III TTC (90 μg/day) is applied as the threshold for systemic toxicity when the Ames test including the process of sample concentration steps provides the negative results.

A Mathematical Approach Using Strat-M to Predict the Percutaneous Absorption of Chemicals under Finite Dose Conditions.

Estimation of the percutaneous absorption is essential for the safety assessment of cosmetic and dermopharmaceutical products. Currently, an artificial membrane, Strat-M, has been focused on as the tool which could obtain the permeation parameters close to the skin-derived values. Nevertheless, few practical methodologies using the permeation parameters for assessing percutaneous absorption under in-use conditions are available.

Positional differences and aging changes in Japanese woman epidermal thickness and corneous thickness determined by OCT (optical coherence tomography).

Background/purpose: A number of studies of the internal structure of Japanese woman's skin are now performed by means of optical coherence tomography (OCT) as a technique capable of visualizing the internal structure in a non-invasive manner.

Methods: We measured the epidermal and corneous thicknesses at 11 sites in 116 healthy female volunteers aged from teens to sixties to examine possible positional differences and aging changes.

Results: The epidermal thickness determined at the 11 sites averaged 68.

Development of a new evaluation method for cheek sagging using a Moire 3D analysis system.

Background/aims: Facial sagging becomes progressively noticeable with aging. Previously developed methods to study facial sagging measure the shape of sagging skin, evaluate skin properties such as elasticity or flexibility or visually score the degree of sagging using a photo scale. However, the practical use of these methods has shortcomings and is thus limited to advanced levels of sagging.

Confocal laser microscopic imaging of conspicuous facial pores in vivo: relation between the appearance and the internal structure of skin.

Background/purpose: Conspicuous facial pores are one of the more serious esthetic defects of most concern to women. Previous microscopic observations of the skin surface around conspicuous pores have discovered large hollows and uneven skin tone. In this study, the observation area was extended from the skin surface to deeper skin to find the characteristic features of conspicuous pores in a wider spectrum.