Polymorphs of o-desmethyl venlafaxine succinate
AssigneeMerck Development Centre Private Limited
InventorsVinayak G. Gore, Vikas S. Kulkarni, V.S. Wakchaure, M.G. Hublikar, S.R. Wavhal
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Abstract
The present invention relates to crystalline forms of O-desmethyl venlafaxine (ODV) succinate monohydrate, namely Forms I and II, in pure form and to novel processes for their preparation. The present invention provides a process for the preparation of Form II free of Form I and a process for the preparation of Form I free of Form II. The present invention provides direct methods for the preparation of ODV succinate Form II from ODV free base and for the preparation of ODV succinate Form I from ODV free base.
Claims20
O-desmethyl venlafaxine succinate Form I or Form II substantially free of other polymorphs.
A direct method for the preparation of O-desmethyl venlafaxine (ODV) succinate Form I or Form II from ODV free base.
A method for the preparation of O-desmethyl venlafaxine (ODV) succinate Form I or Form II without involving any interconversion of ODV succinate polymorphic forms.
A process for the preparation of O-desmethyl venlafaxine (ODV) succinate Form II from ODV free base, comprising the steps of:
- (a) reacting O-desmethyl venlafaxine and succinic acid in (i) toluene and water, (ii) methanol, (iii) methanol and acetone, (iv) water, or (v) acetonitrile and N,N-dimethylformamide;
- (b) cooling the reaction mixture;
- (c) filtering the reaction mixture to obtain a solid product;
- and
- (d) drying the solid product.
A process for the preparation of O-desmethyl venlafaxine (ODV) succinate Form I from ODV free base, comprising the steps of:
- (a) reacting O-desmethyl venlafaxine and succinic acid in N,N-dimethyl-formamide, acetone and water;
- (b) cooling the reaction mixture;
- (c) filtering the reaction mixture to obtain a solid product;
- and
- (d) drying the solid product.
Dependencies are inferred from the claim text.