ANTHOCYANIDIN COMPLEX

Abstract

The invention relates to a complex of an anthocyanidin and a methylated -cyclodextrin which can be formulated as an aqueous solution and as a solid, and to a process for the preparation of such a complex. Complexes according to the invention are storage-stable and can be readily formulated in aqueous solution.

Claims

1. A complex of an anthocyanidin and a methylated -cyclodextrin.

2. The complex as claimed in claim 1, characterized in that the degree of substitution of the -cyclodextrin with methyl groups is from 10 to 15.

3. The complex as claimed in claim 2, characterized in that the methylated -cyclodextrin is randomly methylated -cyclodextrin (RAMEB).

4. The complex as claimed in claim 1, characterized in that the anthocyanidin is selected from the group consisting of aurantinidin, cyanidin, delphinidin, europinidin, luteolinidin, pelargonidin, malvidin, peonidin, petunidin and rosinidin.

5. The complex as claimed in claim 4, characterized in that the anthocyanidin is delphinidin.

6. An aqueous solution of a complex as claimed in claim 1.

7. The aqueous solution as claimed in claim 6, characterized in that the concentration of the anthocyanidin, calculated as chloride, is at least 10 mg/ml.

8. A solid comprising a complex of an anthocyanidin and a methylated -cyclodextrin, obtainable by removing the solvent from an aqueous solution as claimed in claim 6.

9. A process for the preparation of a complex of an anthocyanidin and a methylated -cyclodextrin, comprising the steps: a) preparing an aqueous solution of the methylated -cyclodextrin, b) adding the anthocyanidin and mixing to prepare the complex.

10. The process as claimed in claim 9, characterized in that the solution prepared in step a) comprises from 10 to 60% by weight.

11. The process as claimed in claim 9, characterized in that the mixing in step b) takes place over a period of from 2 to 20 hours.

12. The complex as claimed in claim 1, characterized in that the degree of substitution of the -cyclodextrin with methyl groups is from 11 to 14.

13. The complex as claimed in claim 1, characterized in that the degree of substitution of the -cyclodextrin with methyl groups is from 12 to 13.

14. The aqueous solution as claimed in claim 6, characterized in that the concentration of the anthocyanidin, calculated as chloride, is at least 20 mg/ml.

15. The aqueous solution as claimed in claim 6, characterized in that the concentration of the anthocyanidin, calculated as chloride, is at least 50 mg/ml.

16. The aqueous solution as claimed in claim 6, characterized in that the concentration of the anthocyanidin, calculated as chloride, is at least 80 mg/ml.

17. The process as claimed in claim 9, characterized in that the solution prepared in step a) comprises from 20 to 50% by weight of the methylated -cyclodextrin.

18. The process as claimed in claim 9, characterized in that the solution prepared in step a) comprises from 30 to 50% by weight of the methylated -cyclodextrin.

Description

EXAMPLE 1

Complexing of Delphinidin With RAMEB

[0052] Solutions of 40% by weight RAMEB in water were prepared.

[0053] 1 ml of the aqueous cyclodextrin solution was introduced into a glass flask. 250 mg of delphinidin chloride was then added.

[0054] The suspension was stirred for 4 hours at 30 C. in the dark. It was then filtered through a membrane filter of 0.8 m pore size.

EXAMPLE 2

Preparation of a Solid According to the Invention

[0055] The solution according to example 1 was frozen and then freeze-dried at 48 C. and a pressure of approximately 10.3 Pa (77 mTorr). This gave 0.36 g of a solid with a delphinidin content of 31.1% by weight.

[0056] This solid provides delphinidin in high concentration in a storable and readily in vivo administrable form. The delphinidin content of the complex is much higher than in the prior art.