Madaus Ag

Laboratoire Medidom Sa

Alfons Carcasona

Klaus Witthohn

Wolf Grimminger

Helga Zaeske

Pentti Hietala

Pentti H&ecirc;itala

Pentti Heitala

The present invention provides a process for obtaining diacetylrhein, wherein diacetylrhein containing aloe-emodin components is subjected to a liquid&mdash;liquid partitioning between a polar organic solvent which is only partly miscible with water and an aqueous phase of pH 6.5 to 7.5 and the diacetylrhein is recovered and optionally recrystallized. The present invention is also concerned with diacetylrhein obtainable by this process and with pharmaceutical compositions containing it.

Process for production of diacetylrhein

The present invention provides a process for treating arthritis utilizing substantially pure diacetylrhein having an aloe-emodin content of less than 20 ppm.

Method of preparing diacetyl rhein

Sennosides A, B and Al of the formula: ##STR1## which are substantially free from sennosides C, D and Dl, and from aloe-emodin derivatives, are prepared by a process wherein a) a sennoside mixture is reduced to rhein-9-anthrone-8-glucoside and aloe-emodin-9-anthrone-8-glucoside, b) a liquid-liquid partitioning of the compounds obtained is carried out between a polar organic solvent which is only partly miscible with water and an aqueous phase and c) the rhein-9-anthrone-8-glycosides contained after the partitioning in the aqueous phase is again oxidized to the corresponding sennosides and these are recovered.

Method of extracting sennosides A, B and A1

Diacetylrhein which is substantially free of aloe-emodin components, is prepared by a process wherein

The present invention provides a process for obtaining diacetylrhein, wherein diacetylrhein containing aloe-emodin components is subjected to a liquid-liquid partitioning between a polar organic solvent which is only partly miscible with water and an aqueous phase of pH 6.5. to 7.5 and the diacetylrhein is recovered and optionally recrystallised. The present invention is also concerned with diacetylrhein obtainable by this process and with pharmaceutical compositions containing it.

Growing community of inventors

Kö'ln, Germany

Alfons Carcasona