An in vitro Pig Skin Model for Predicting Human Skin Penetration and Irritation Potential

Predicting Passive and Active Tissue:Plasma Partition Coefficients: Interindividual and Interspecies Variability

“…For example, the pig and beagle dog skin predictions were most similar to that of the human. This is expected because pig skin is routinely used as a model for human chemical dermal absorption studies because of its similarity to human skin …”

Multiple topical product dermatitis: Paradigms in understanding and future perspectives

“…For instance, prior work has demonstrated that in vitro and in vivo studies correlate well when alterations occur exclusively to the stratum corneum barrier, however when effects extend to the viable layers (e.g., vesiculation, erythema), then in vitro data may under-estimate delivery/irritancy. [90][91][92] To our knowledge, none of the currently available methods are validated for multiple exposures. Further work needs to be done to provide a standardised framework for the way these tests are conducted, analysed and ultimately interpreted in the context of multiple product exposures.…”

“…This is not a new concept-the idea of Mechanistically-Defined Chemical Mixtures, is a conceptual framework introduced more than 20 years ago, whereby components of a formulation can alter the active component/s' absorption thereby altering pharmacological and toxicological effects. 90,[102][103][104] Complex effects at different depths of the skin from the surface are also possible (Figure 3b,c). This includes the skin surface (e.g., chemical−chemical interactions, altered physicochemical properties, altered evaporation, binding to adnexal structure or their products such as sweat or sebum), stratum corneum (lipid extraction, altered partitioning into or through corneocytes/lipids), epidermis (biotransformation) and dermis (blood flow).…”

“…Key limitations of the in vitro approaches are that they may not represent in use situations, lack complexities of native skin (e.g., hair follicles, sweat glands) and may overestimate irritancy or under‐estimate irritancy by cumulative irritants. For instance, prior work has demonstrated that in vitro and in vivo studies correlate well when alterations occur exclusively to the stratum corneum barrier, however when effects extend to the viable layers (e.g., vesiculation, erythema), then in vitro data may under‐estimate delivery/irritancy 90–92 . To our knowledge, none of the currently available methods are validated for multiple exposures.…”

“…Studies are typically performed in Franz cells with excised skin investigating one product over time, however in reality, consumers apply and layer multiple products (Figure 3a). This is not a new concept—the idea of Mechanistically‐Defined Chemical Mixtures, is a conceptual framework introduced more than 20 years ago, whereby components of a formulation can alter the active component/s' absorption thereby altering pharmacological and toxicological effects 90,102–104 …”