Nanotechnology in cosmetics.

Nanomaterials are being used in cosmetic products for various effects. However, their use also raises potential safety concerns. Some of these concerns can be addressed by determining the type of nanomaterials used, as well as stability, potential for skin absorption, route of exposure, and how they are formulated in cosmetic products.

In vivo and in vitro skin absorption of lipophilic compounds, dibutyl phthalate, farnesol and geraniol in the hairless guinea pig.

The relationship between in vitro and in vivo skin absorption of lipophilic cosmetic ingredients (dibutyl phthalate (DBP, Log K(ow): 4.45), farnesol (Log K(ow): 5.77) and geraniol (Log K(ow): 3.

In vitro and in vivo percutaneous absorption of retinol from cosmetic formulations: significance of the skin reservoir and prediction of systemic absorption.

The percutaneous absorption of retinol (Vitamin A) from cosmetic formulations was studied to predict systemic absorption and to understand the significance of the skin reservoir in in vitro absorption studies. Viable skin from fuzzy rat or human subjects was assembled in flow-through diffusion cells for in vitro absorption studies. In vivo absorption studies using fuzzy rats were performed in glass metabolism cages for collection of urine, feces, and body content.

In vitro dermal absorption and metabolism of D&C red no. 17 in human and porcineskin.

D&C red no. 17 is approved for use in externally applied drug and cosmetic applications, in amounts consistent with good manufacturing practice. Concerns about the safety of the color additive (1-[4-phenylazophenylazo]-2-napthol (PAN) is the primary color constituent) have been raised due to potential metabolic cleavage of PAN to yield 4-aminoazobenzene.

Absorption of lawsone through human skin.

Lawsone (2-hydroxy-1,4-naphthoquinone) is the principal color ingredient in henna, a color additive approved with limitations for coloring hair by the Food and Drug Administration (FDA) under 21 CFR 73.2190. In 2002, the scientific committee on cosmetics and non-food products (SCCNFP), now known as the scientific committee for consumer products (SCCP), evaluated the safety of lawsone as a coloring agent in hair dye products of the European Union (EU).

Fate of chemicals in skin after dermal application: does the in vitro skin reservoir affect the estimate of systemic absorption?

Recent international guidelines for the conduct of in vitro skin absorption studies put forward different approaches for addressing the status of chemicals remaining in the stratum corneum and epidermis/dermis at the end of a study. The present study investigated the fate of three chemicals [dihydroxyacetone (DHA), 7-(2H-naphtho[1,2-d]triazol-2-yl)-3-phenylcoumarin (7NTPC), and disperse blue 1 (DB1)] in an in vitro absorption study. In these studies, human and fuzzy rat skin penetration and absorption were determined over 24 or 72 h in flow-through diffusion cells.