Combinations of isomers of dihydrotetrabenazine
This invention relates to the use of combinations of stereoisomers of dihydrotetrabenazine for the treatment of movement disorders, such as Tourette's syndrome.
1. A pharmaceutical combination comprising:
(a) (+)-β-dihydrotetrabenazine, or a pharmaceutically acceptable salt thereof;
(b) (−)-α-dihydrotetrabenazine, or a pharmaceutically acceptable salt thereof; and
(c) (+)-α-dihydrotetrabenazine, or a pharmaceutically acceptable salt thereof.
2. A pharmaceutical combination according to claim 1 which comprises from 35 to 75 parts by weight of (+)-β-dihydrotetrabenazine and from 25 to 55 parts by weight of a mixture of (+)-α-dihydrotetrabenazine and (−)-α-dihydrotetrabenazine.
3. A pharmaceutical combination according to claim 1 comprising:
(a) 40-65 parts by weight of (+)-β-dihydrotetrabenazine, or a pharmaceutically acceptable salt thereof; and
(c) 40-65 parts by weight of (+)-α-dihydrotetrabenazine, or a pharmaceutically acceptable salt thereof.
4. A pharmaceutical combination according to claim 3 comprising:
(a) 45-55 parts by weight of (+)-β-dihydrotetrabenazine, or a pharmaceutically acceptable salt thereof; and
(c) 45-55 parts by weight of (+)-α-dihydrotetrabenazine, or a pharmaceutically acceptable salt thereof.
5. A pharmaceutical combination according to claim 2 which comprises:
(a) 45-65 parts by weight of (+)-β-dihydrotetrabenazine, or a pharmaceutically acceptable salt thereof;
(b) 30-50 parts by weight of (−)-α-dihydrotetrabenazine, or a pharmaceutically acceptable salt thereof; and optionally
(c) 0.1-5 parts by weight of (+)-α-dihydrotetrabenazine, or a pharmaceutically acceptable salt thereof.
6. A pharmaceutical unit dosage form comprising a pharmaceutically acceptable excipient and a pharmaceutical combination as defined in claim 1 .
7. A pharmaceutical unit dosage form according to claim 6 wherein the sum of the amounts of (+)-β-dihydrotetrabenazine, (−)-α-dihydrotetrabenazine and (+)-α-dihydrotetrabenazine does not exceed 100 mg.
8. A pharmaceutical unit dosage form according to claim 6 which is selected from capsules and tablets.
9. A pharmaceutical combination according to claim 1 wherein the combination is substantially free of (−)-β-dihydrotetrabenazine.
10. A pharmaceutical combination according to claim 1 wherein the combination contains less than 3% of (−)-β-dihydrotetrabenazine by weight compared to the total weight of all isomers of dihydrotetrabenazine present.
11. A pharmaceutical unit dosage form according to claim 6 wherein the combination is substantially free of (−)-β-dihydrotetrabenazine.
12. A pharmaceutical unit dosage form according to claim 6 wherein the combination contains less than 3% of (−)-β-dihydrotetrabenazine by weight compared to the total weight of all isomers of dihydrotetrabenazine present.