Apomorphine has a catechol element and belongs to a class called β-phenylethylamines and its main components are similar to the dopamine structure. The effect that apomorphine has on the dopamine receptors can also be linked to the similarities between its structure and dopamine. It is a chiral molecule and thus can be acquired in both the R and S form, the R form is the one that is used in therapy. When apomorphine interacts with the dopamine receptor, or the ATP on the receptor, the catechol and nitrogen are important to stabilize the structure with hydrogen bonding. The position of the hydroxyl groups is also important and monohydroxy derivatives have been found to be less potent than the dihydroxy groups. There are a number of stability concerns with apomorphine such as oxidation and racemization.