The present invention relates to novel crystalline form(s) of water-soluble salts and of free base of a cdk inhibitor. Such crystal salts are for example fumarate, L-malate, maleate, succinate, adipate, malonate, glycolate, phosphate, mesylate, L-lactate, hydrochloride, di-hydrochloride, tri-hydrochloride. Hydrates and polymorphs of such new salt forms, a process for their preparation, their utility in therapy and to the pharmaceutical compositions containing them are also claimed and described in the present application.
