Abstract: 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 recrystallized. The present invention is also concerned with diacetylrhein obtainable by this process and with pharmaceutical compositions containing it.

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

Abstract: The present invention provides a process for the production of a flavanolignan preparation with an improved liberation in comparison with one of the pure flavanolignans, characterised in that a) an aqueous-alcoholic solution of pharmaceutically-acceptable carrier materials and wetting agents is prepared, a flavanolignan is suspended in this solution and the mixture obtained is heated to the boiling temperature in order to form a clear solution or b) a flavanolignan and a wetting agent is suspended in alcohol, the suspension obtained is heated with stirring up to the formation of a clear solution, this is mixed with an aqueous solution of pharmaceutically-acceptable carrier materials and the mixture obtained is heated with stirring until a clear solution is present and that subsequently the clear solution obtained according to a) or b) is concentrated for the formation of a co-precipitate, filtered and the resulting co-precipitate dried in a vacuum.

Abstract: The present invention provides a process for the production of a flavanolignan preparation with an improved liberation in comparison with one of the pure flavanolignans, characterized in that a) an aqueous-alcoholic solution of pharmaceutically-acceptable carrier materials and wetting agents is prepared, a flavanolignan is suspended in this solution and the mixture obtained is heated to the boiling temperature in order to form a clear solution or b) a flavanolignan and a wetting agent is suspended in alcohol, the suspension obtained is heated with stirring up to the formation of a clear solution, this is mixed with an aqueous solution of pharmaceutically-acceptable carrier materials and the mixture obtained is heated with stirring until a clear solution is present and that subsequently the clear solution obtained according to a) or b) is concentrated for the formation of a co-precipitate, filtered and the resulting co-precipitate dried in a vacuum.

Abstract: 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 whereina) 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 andc) 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.

Abstract: Diacetylrhein which is substantially free of aloe-emodin components, is prepared by a process whereina) rhein-9-anthrone-8-glusoside containing aloe-emodin components is subjected to 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,b) the rhein-9-anthrone-8-glucoside contained after the partitioning in the aqueous phase is oxidized to rhein-8-glucoside,c) the glucose residue in the 8-position of the rhein-8-glucoside is split off in an acidic medium and,d) the rhein obtained is acetylated and the diacetylrhein recovered.

Abstract: 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.