PROCESS FOR PREPARATION OF CRYSTALLINE CLOPIDOGREL HYDROGEN SULPHATE FORM I

摘要

The present invention describes an improved industrial process for crystallizing out polymorph‘Form I’of (+) clopidogrel hydrogen sulphate (also called clopidogrel bisulphate) in) from either a Type-1 solvent or liquid characterized by comprising two or more functional groups or their mixtures thereof; or a Type-II solvent and/or solvent mixture selected from the group of methyl ethyl ketone, cyclopentylmethyl ether, dipropylglycolether, dibutylglycol ether, propylmethyl cellosolve, butylmethylcellosolve, propylethylellosolve, butylethylcellosolve or their cross combinations in a reproducible manner without detectable contamination of polymorph designated as‘Form II’. The invention also discloses improvements in the preparation of clopidogrel free base and process for recovery and recycling of resolving agent camphor sulphonic acid.