Molecular pharmaceutics play a critical role in the drug delivery system, representing the direct interconnection of drug bioavailability with its molecular form. There is a diversity in the molecular structures by which it affects its properties, such as amorphous form, crystalline form, partialamorphous molecular dispersion, and disordered state. The active pharmaceutical ingredient (API) and the excipients utilized in the formulation process contain various divergent modes used in the formulation process. They include better formulations of any type to obtain good quality pharmaceutical products. This review reveals how the molecular states affect the API and are important in maintaining the quality of dosage forms. Furthermore, the physio-chemical properties of the components and various pharmaceutical approaches employed in the formulation of dosage forms are studied from the point of view of molecular pharmaceutics.