Process for drying bendamustine hydrochloride monohydrate

Abstract

Wet bendamustine hydrochloride monohydrate may be dried by a two stage process wherein rapid drying is first carried out to provide a partially dried product, which is then further dried using an inert gas of controlled relative humidity to yield dry bendamustine hydrochloride monohydrate.

1 .- 18 . (canceled) 
     
     
         19 . Dry bendamustine hydrochloride monohydrate produced by the method of claim  1 . 
     
     
         20 . Dry bendamustine hydrochloride monohydrate, containing less than 0.15%, as determined by HPLC area %, of monohydroxy-bendamustine. 
     
     
         21 . The dry bendamustine hydrochloride monohydrate of  claim 20 , containing less than 0.05%, as determined by HPLC area %, of monohydroxy-bendamustine. 
     
     
         22 . Dry bendamustine hydrochloride monohydrate, substantially free of any other physical form of bendamustine hydrochloride. 
     
     
         23 . Dry bendamustine hydrochloride monohydrate, substantially free of anhydrous bendamustine hydrochloride.