u2212 lofexidine and lofexidine the processes for the preparation of enantiomerically pure r or s u2212 lofexidine 2 1 2 6 dichlorophenoxy ethyl 4 5 dihydro 1h imidazole or pharmaceutically acceptable salts thereof by resolution of r s lofexidine hydrochloride with di p toluoyl d tartaric acid and s mandelic to form a mixture of diastereomeric salts separating these salts by kinetic resolution in a mixture of solvent systems of the kind such as herein described in the specified time and temperature range to provide said r lofexidine hydrochloride or s u2212 lofexidine hydrochloride with excellent chiral purity more than 99 9 more particularly it relates to the preparation of pure lofexidine hydrochloride a reacting a racemic form of lofexidine with an aliphatic or aromatic chiral acid or an aliphatic or aromatic u2212 chiral acid such as but not limited to tartarate lactate citrate mandelate fumerate citrate abscisic acid 3 hydroxyisobutyric acid cholic acid deoxycholic acid aminoacids glycocholic acid and related steroid carboxylic acids in order to form a mixture of the u2212 and diastereomeric lofexidine salts or u2212 u2212 and u2212 diastereomeric lofexidine salts respectively b separating the diastereomeric salts i e u2212 lofexidine salt from the lofexidine salt or the u2212 u2212 lofexidine salt from the u2212 lofexidine salt by a process of fractional crystallization or by a preparative chromatographic process or preferential adsorption method c treating the u2212 lofexidine salt or the u2212 u2212 lofexidine salt so obtained with base to liberate u2212 lofexidine d treating the lofexidine salt or the u2212 lofexidine salt so obtained with base to liberate lofexidine and e utilizing a chiral chromatographic matrix to separate a racemic mixture of lofexidine into.