The present invention provides solid crystalline forms of apomorphine free base or a hydrate, solvate, or co-crystals thereof. Such crystalline forms may be advantageous over amorphous forms of apomorphine, e.g., amorphous salt forms such as acid addition salts of apomorphine, because of their increased/greater stability and/or improved pharmacological properties, e.g., decreased adverse reactions at the site of administration. The invention further provides liquid formulations obtained by dissolving said crystalline forms of apomorphine in a solvent, as well as a method for treatment of a neurological or movement disorder, e.g., Parkinson's disease, or a condition associated therewith, by administration of said liquid formulations.
