A novel crystal form the pharmaceutical compound olanzapine, processes for its preparation and its pharmaceutical use are disclosed.

This invention encompasses methods of synthesizing olanzapine without solvents or by using low boiling organic solvents.

The invention is directed to a series of novel crystalline olanzapine forms, in particular hydrated and solvated crystalline forms of olanzapine, methods of use in pharmaceutical compositions, and method of treating psychiatric disorders using the crystalline forms. One series of the crystalline forms are hydrates, i.e. water containing crystals, wherein water may be present in a ratio of about 2:1.5 to a ratio of about 1:3 olanzapine:water, while another includes solvates such as an isobutanol solvate. The olanzapine crystalline forms include Forms H, G, Y, X, K, S, Q, Z, and J.

A process for the preparation of polymorph Form I of 2-methyl-4-(4-methyl-1-piperazinyl)-10H-thieno[2,3-b][1,5] benzodiazepine, or olanzapine.