Capacity of an in vitro rat skin model to predict human dermal absorption: Influences of aging and anatomical site

Abstract

In addition to inhalation, dermal absorption is a route of exposure to be considered when assessing occupational risks. To investigate dermal penetration of chemicals, human skin samples are regarded as the gold standard. As human samples can be difficult to obtain, many experiments are performed with rat skins, and the results extrapolated to describe human percutaneous absorption. Here, we examined the characteristics of rat skin samples and compared absorption to that measured with in vitro human skin. The thickness of the stratum corneum layer in rat skin samples was found to be uniform when samples were excised from the animals' backs once they were at least 7-weeks-old. Overall, dorsal skin samples from mature rats could be reliably used to measure the flux of hydrophilic liquid molecules, such as N-methyl-2-pyrrolidone, and N,N-dimethylformamide. In contrast, with a solid lipophilic substance, bisphenol A, dissolved in acetone, the flux obtained with rat skin samples was 3-fold higher than that measured with human skin. Consequently, it does not appear relevant to use rat skin in place of human skin to measure absorption of solid lipophilic substances.

In vivo Guinea Pig Model Study for Evaluating Antifungal Effect of a Dual-Diode Laser with Wavelengths of 405 Nm and 635 Nm on Dermatophytosis

“…4 The treatment parameters of the 405-/635-nm dual-diode laser in our experimental study were determined according to the previous clinical reports. 4,18 The simultaneously activated wavelengths of 405 nm at a power of 24 mW and 635 nm at 18 mW for 12 min have been known to be unaffecting temperature changes in treated areas. 4 In our study, the 405-/635-nm dual-diode laser treatment in guinea pigs with dermatophytosis achieved 87.5% negative conversion of mycologic studies.…”

“…This study used guinea pigs to develop an in vivo animal model of dermatophytosis because their skin shares many structural similarities with human skin. 18 Then, the skin of guinea pigs was infected with mixed preparation of T. rubrum and T. mentagrophytes suspensions to reduce the number of enrolled experimental animals. Mycological studies using scraped samples after completing six sessions of dual-diode laser treatment in the infected guinea pig groups revealed that seven of eight (87.5%) samples in each group had negative results in direct KOH microscopy and fungal culture studies.…”

Reprogramming of Rat Fibroblasts into Induced Neurons by Small-Molecule Compounds In Vitro and In Vivo

“…Studies on the efficacy of iNs obtained by this method in treating animal models of neurodegenerative diseases, such as AD and PD, are needed. In addition, although there are few genetic similarities between Homo sapiens and Rattus norvegicus, rat cells are widely used in experiments to provide a foundation for human research. − However, rats and humans are different species, so whether this method has good efficacy when applied to human cells needs to be verified in future experiments.…”

Combinatorial drug‐loaded quality by design adapted transliposome gel formulation for dermal delivery: In vitro and dermatokinetic study

“…Rat skin was taken for the study although there is different rate of absorption of drugs as compare to human skin but we can compute and correlate it with human skin permeation and absorption 36 . Franz diffusion cells having diffusion area 0.785 cm 2 of 10 mL volume of receptor were used to measure the rate of skin penetration.…”