Formulation of drugs into various dosage forms may modify profoundly the onset, intensity, and duration of physiological response, the correct dosage for the patient, the incidence and intensity of side effects, and the stability of the drugs. These effects are illustrated by examples from the clinical and scientific literature. Because of the modifications discussed, it is clear that in some cases choice of dosage form and manufacturer's brand may be as important as choice of the actual therapeutic agent.
Levy G, Nelson E. Pharmaceutical Formulation and Therapeutic Efficacy. JAMA. 1961;177(10):689-691. doi:10.1001/jama.1961.03040360025004