Solid Forms of Pharmaceutical Molecules

Abstract

A drug discovery is characterized by two stages. The first in terms of time is called “lead structure”, followed by a so called “drug candidate” stage. The lead structure stage involves selecting the optimum molecule of the pharmaceutical, while drug candidate stage means selecting the optimum solid form. Usually, five to ten candidates pass to the drug candidate stage and the result is the selection of the final solid API (Active Pharmaceutical Ingredience) for the ensuing formulation of the solid dosage form. The lead structure stage concerns only the discovery of the original drug, the drug candidate stage may concern also generics (a drug which is bioequivalent with original and is produced and distributed after the patent protection of the original).