Question

What properties of a crystal form lets us know if it can be classified as a drug substance?

Answer 1

The physical properties of the solid-state seen in crystals and powders of both drugs and pharmaceutical excipients are of interest because they can affect both the production of dosage forms and the performance of the finished product.

Drug molecules usually have triclinic, monoclinic or orthorhombic unit cells. The ability to inject a suspension contain- ing a drug in crystal form will be influenced by the habit: plate-like crystals are easier to inject through a fine needle than are needle-like crystals