**2.1 Preformulation studies: an essential concept in formulation development**

Preformulation is the vital concept for final formulation dosage form development intended to target disease as a result preformulation studies are carried out to generate usable data and uncover crucial information that innovators and industry professionals may utilise to produce dosage forms that are stable effective and safe for end users patients it is the main step toward the creation of final dosage form it encompasses comprehensive knowledge of physicochemical aspects of the drug and mixing with appropriate adjuvants to the final design of effective, safe and stable drug delivery system [21]. But it is noteworthy to have data evidence about the basic properties of the drug molecule, its stability information, pharmacokinetic data of lead drug molecules or the same kind of molecule available in the market and bioavailability profile, and feasible route of drug administration before preformulation studies [22]. Additionally, it includes the molecular optimization of the API to change its dissolution and solubility behaviour, for example, salt production techniques have been commonly used to boost solubility, its rate of dissolution (diclofenac sodium salt) and prodrug approach (Levodopa and Enalapril). Also, it determines the connection between physicochemical variables and the kinetic profiles of a novel drug moiety and investigation several aspects of an API's bulk, solubility, stability and compatibility of drug and excipients [23, 24].

### *Preformulation Studies: A Versatile Tool in Formulation Design DOI: http://dx.doi.org/10.5772/intechopen.110346*

Biotherapeutics (Vaccine, proteins and peptides preformulation studies) development into a drug candidate has many difficulties associated with a drug's clinical effectiveness in patients depending on the unique physicochemical and biological features of a given biotherapeutic molecule, including stability, viscosity, manufacture ability, bioavailability, and immunogenicity. To overcome these challenges before being developed a final dosage form is covered under preformulation studies for monoclonal antibodies, peptides, and proteins. The methods used to analyse the candidate macromolecules' primary, secondary, and tertiary structures, along with tests to determine the types and concentrations of contaminants, are the first steps in the process. Then, for the best possible potential to develop the intended biological products, the functions of the various compounds are evaluated using various screening procedures, along with research on their solubility and stability [25]. As a result, it will eventually open the door for the creation of dosage forms that are acceptable to patients and have high levels of stability, safety, efficacy, and are low-cost affordable dosage forms for the patients.
