Process for the preparation of dexlansoprazole
The present invention relates to a process for the preparation of crystalline dexlansoprazole.
1. A process for the preparation of crystalline dexlansoprazole, the process comprising the steps of:
a) treating a salt of dexlansoprazole with an agent capable of liberating dexlansoprazole as a free base in the presence of a solvent;
b) treating the dexlansoprazole obtained in step a) with a solvent selected from the group consisting of water, halogenated hydrocarbon, C1-3 alkanol, ether and a mixture thereof; and
c) isolating crystalline dexlansoprazole from the mixture thereof.
2. A process according to claim 1 , wherein the agent capable of liberating dexlansoprazole is amine salt or hydrogen sulfate.
3. A process according to claim 2 , wherein the hydrogen sulfate is sodium hydrogen sulfate, potassium hydrogen sulfate or both.
4. A process according to claim 1 , wherein the salt of dexlansoprazole is alkali metal salt or alkaline earth metal salt.
5. A process according to claim 4 , wherein the alkali metal salt of dexlansoprazole is sodium salt.
6. A process according to claim 1 , wherein the solvent used in step a) is a water miscible solvent.
7. A process according to claim 6 , wherein the water miscible solvent is acetone, C1-3 alkanol, dioxane, tetrahydrofuran, dimethylformamide, acetonitrile, dimethylsulfoxide or a mixture thereof.
8. A process according to claim 1 , wherein the halogenated hydrocarbon solvent used in step b) is dichloromethane.
9. A process according to claim 1 , wherein the C1-3 alkanol solvent used in step b) is methanol.
10. A process according to claim 1 , wherein the ether solvent used in step b) is methyl t-butyl ether, diisopropyl ether or a mixture thereof.
11. A process according to claim 1 , wherein crystalline dexlansoprazole obtained in step c) has chromatographic purity of at least 99%.
12. A process according to claim 1 , wherein crystalline dexlansoprazole obtained in step c) has sulfone impurity of not more than 0.1%.
13. A process according to claim 1 , wherein crystalline dexlansoprazole obtained in step c) has water content of not more than 0.2%.
14. A process according to claim 1 , wherein crystalline dexlansoprazole obtained in step c) has sulfone impurity of not more than 0.1% and water content not more than 0.2%.