Ammonium bituminosulfonate
Ichthammol or ammonium bituminosulfonate, also known as black ointment, is a medication derived from sulfur-rich oil shale. It is used as a treatment for different skin diseases, including eczema and psoriasis. It is applied on the skin as an ointments, most commonly containing 10% or 20% ichthammol.
Bituminosulfonates are considered topical therapeutic agents with very good tolerability.
The use of ichthammol in dermatology was promoted by German physician Paul Gerson Unna.
Ichthammol ointments, commonly known as black ointment or drawing salve, should not be confused with black salve, an escharotic paste intended to destroy skin tissue. In contrast, ichthammol does not have any corrosive properties on the skin.
Production
Ichthammol is obtained through three steps from bituminous schists: dry distillation, sulfonation of the resulting oil, and finally neutralization with ammonia.Properties
Ichthammol is a viscous, water-soluble substance with a characteristic bitumen-like odor. It is incompatible with acids, alkali carbonates or hydrates and alkaloidal salts. It is a thick reddish brown liquid, possessing a bituminous odor and taste. It is soluble in water and miscible with glycerin, but is nearly insoluble in strong alcohol or concentrated ether. It contains a large percentage of organically combined sulfur.Chemically speaking ichthammol is a sulfonated shale oil. From elemental analysis, the composition of ichthammol was calculated to be C28H36S5O62. However, as a product of natural origin, it is a mixture of many different compounds.
Similar materials
Similar substances can be made by altering the starting material. An "ammonium sufobitol", made from light shale oil of the Messel pit, was sold until 2000 in Germany. The Chinese material labelled as "ichthammol" are actually an ersatz product made from vegetable oil.Ichtasol
Ichtasol is produced from the light fraction of distilled shale oil. It has a pale appearance. There appears to be an oral preparation made from this mixture.Chinese vegetable oil product
"Ichthammol" made in China does not meet standards for ichthammol as specified in United States Pharmacopoeia, European Pharmacopoeia, or for the CAS number. Instead of requiring bituminous schists like these definitions, the Chinese Pharmacopoeia definition for "ichthammol" uses ordinary vegetable oil:Ichthammol is a mixture obtained by sulfurization of vegetable oils, sulfonation, and neutralization with ammonia. Organic sulfur content ≥ 5.5%, ammonium content ≥ 2.5%. — Chinese definition according to ChP 10
As a result, Chinese "ichthammol" is very different from standard ichthammol. The characteristic bitumen-like odor is missing with Chinese material.
Medical use
Skin disorders
It is used to treat a variety of skin disorders as e.g. eczema, psoriasis, Acne rosacea and acne.According to the "list of preferred Specials" by the British Association of Dermatologists ichthammol can be used in dermatology prescribing to treat acutely inflamed atopic eczema, among others. A corresponding recommendation exists for bituminosulfonates in Germany. According to "guideline atopic eczema" bituminosulfonates can be considered for treatment of atopic eczema based on general clinic experience. In the European Dermatology Forum guidelines for treatment of atopic eczema ichthammol is recommended as a useful addition to the basic treatment regimen, especially in mild disease or if TCS treatment is not possible from a patient's perspective, e.g. corticophobia.