Newborn pig skin as model membrane in in vitro drug permeation studies : a technical note

The suitability of newborn pig skin as an alternative to human epidermis in in vitro permeation studies was investigated. A set of 7 benzoxazinones was used to perform in vitro experiments by using a modified Franz diffusion cell and excised newborn pig skin as a membrane. The maximum flux through newborn pig skin (Jmax,p) was compared with the maximum flux through excised human epidermis (Jmax,h), available from the literature, by means of the factor of difference value FoD = Jmax,p/Jmax,h. The FoD values ranged from 0.48 to 1.91, indicating that Jmax,p and Jmax,h were in the same order of magnitude. This result confirmed the suitability of this membrane to assess the permeability of not completely freely water soluble drugs, such as the set of benzoxazinones used in the present study and propranolol hydrochloride. Considering that the skin was withdrawn from animals that died of natural causes, the ethical problems connected with the use of animal skin in preliminary permeation screenings can be bypassed