Histological dermal changes caused by preparation and application procedures in percutaneous dose toxicity studies in dogs, rabbits and rats

Abstract

We reevaluated histological slides of dorsal skin in control animals from past percutaneous dose toxicity studies using dogs, rabbits and rats to provide background data concerning histological changes related to preparation and application procedures and vehicles or embrocations of every variety. Acanthosis, dermal or perifollicular inflammatory cell infiltration in dogs; hyperkeratosis, acanthosis, dermal inflammatory cell infiltration or hemorrhage in rabbits; and acanthosis, dermal inflammatory cell infiltration, crust or foreign body granuloma in rats were present as procedure-related underlying histological changes in the control animals. Four mechanical acts, (1) rubbing with gauze to remove an administered substance for reapplication, (2) use of a taut bandage to avoid slipping from the application site, (3) peeling a patch off as a preparation procedure for reapplication, and (4) clipping or shaving, were considered to cause injury to the skin. The degree of influence of the various application procedures was found to be as follows: sham, lotion < cream < ointment and tape in dogs; untreated control, sham < lotion < tape and poultice in rabbits; and sham, sodium carboxymethylcellulose < olive oil and lotion < ointment and tape in rats. The degree of ointment influence on rabbits is equivocal.

Optimization, Development, and Safety Evaluation of Olive Oil Nanoemulsion for Topical Application: A Response Surface Methodology

“…Strong irritant substances cause erythema and edema and a variety of histological changes such as erosion or ulcer and inflammation that ranges in severity depending on the intensity. Mild or moderate amounts of the irritant substances on the other hand, does not erode the epidermis, but it shows reactive changes such as hyperkeratosis and acanthosis [36]. Absence of these reactions reflects no irritancy.…”

Formulation and In Vitro in Vivo Evaluation of Anti-Acne Gel Containing Peanut Skin Extract

“…Peanut extractMicroscopic examination of skin of rats treated with Peanut extract did not show any lesion of pathological lesion24 .Results obtained from the histological studies showed that the prepared Peanut extract formulation was effective in the treatment of acne.Also Microscopic examination of skin of rats treated with Peanut extract did not show any lesion of pathological lesion.Showing normal histology, Epidermis(Ep), Dermis(De), Hair Follicle(HF) {H&E, 400X} Marketed productMicroscopic examination of skin of rats treated with marketed products did not show any lesion of pathological lesion. Comparison of the control sample treated Peanut extract and marketed products did not show any lesion of pathological lesion.…”