In vitro investigation of the principle of action of ammonium bituminosulfonate ointments on a 3D skin model

Ammonium bituminosulfonate preparations have been used for various dermatological diseases since the 19th century. The dark preparation is known as the so-called "drawing salve" (Ichtholan®) for the treatment of abscesses and furuncles. The underlying activity is in part the loosening of the skin, which facilitates pus extraction and treatment of deep inflammations. For this investigation 3D skin models were incubated with ointments containing different ammonium bituminosulfonate concentrations. Histological and immunohistochemical staining as well as penetration investigation were carried out. The effect of dark ammonium bituminosulfonate ointments on skin loosening was investigated to reveal the underlying mechanism. The skin loosening effect could be proved by HE-staining for ammonium bituminosulfonate treated skin models. This effect was concentration dependent. While treatment with ammonium bituminosulfonate ointment had no influence on keratin expression, high concentrated ointments led to decreased filaggrin and laminin expression. Treatment of skin models with ABS ointments led to an increased skin permeability, which was concentration dependent. For the first time the skin loosening effect of ammonium bituminosulfonate ointment has been demonstrated on 3D skin models. This effect is at least in part caused by the interaction of the substance with structure dependent proteins of the epidermis.