Process for the preparation of Carvedilol Form II
A cost-effective, industrially feasible process for the manufacture of crystalline Carvedilol Form-II using novel Carvedilol salts comprises the steps of reacting 4-(2,3-epoxy propoxy)carbazole (II) with 2-(2-methoxy phenoxy)ethyl amine (III) followed by acidification with mineral acid in presence of an organic solvent to yield acid addition salts, treatment of the said salts with base(s) in presence of organic solvent(s), water and isolation from the organic solvent(s) followed by crystallization from ethyl acetate.
1. A process for the preparation of Carvedilol salts, comprising the steps of:
reacting 4-(2,3-epoxy propoxy) carbazole with 2-(2-methoxy phenoxy) ethylamine in the molar ratio of 1:2.0 to 1:2.5 in presence of at least one organic solvent;
adjusting the pH after completion of the reaction with at least one organic acid in the presence of water and at least one organic solvent: and
isolating the produced Carvedilol salts.
2. A process as claimed in claim 1 , wherein the at least one organic acid is selected from oxalic acid and salicylic acid.
3. A process as claimed in claim 1 , wherein the pH is adjusted to 2.0 to about 3.0.
4. A process as claimed in claim 1 , wherein the at least one organic solvent used during pH adjustment is selected from isopropyl acetate, chlorobenzene and mixtures thereof.
5. A process as claimed in claim 3 , wherein the pH is adjusted to 2.5 to about 2.8.