Discovery of a replacement drug entity may be a huge milestone in science and it becomes even more important if it passes toxicity screening because the potential benefits overweigh the side effects. The last word effect of the new chemical entity depends on its availability at the location of action once it's administered through appropriate route in appropriate form. So for this reason, a replacement challenge is obtainable after successful pharmaceutical and toxicological screening that's to rework potential active new drug entity into a pharmaceutical formulation. It are often broadly elaborated as “a phase which works on study of physical, chemical, analytical, pharmacokinetic, and pharmacodynamic properties of latest chemical entity and utilize the obtained results to style and develop an efficient , stable, and a safer dosage form.” Preformulation study may be a phase which is initiated once the new molecule is seeded. During a broader way, it deals with studies of physical, chemical, analytical, and pharmaceutical properties associated with molecule and provides idea about suitable modification in molecule to point out a far better performance.

Before starting the preformulation studies we should always know the properties of the drug, potency relative to the competitive products and therefore the dosage form, literature search providing stability and decay data, the proposed route of drug administration, literature search regarding the formulation approaches, bioavailability and pharmacokinetics of chemically related drugs. It also includes preliminary investigations and molecular optimization by the drug should be tested to work out the magnitude of every Suspected problem area (Step I), if a deficiency is detected, a molecular modification should be done(Step II). To beat this deficiency molecular modification is completed be salts, prodrugs, solvates, polymorphs or maybe new analogues.

The preliminary objective of preformulation phase or study is to get down foundation for transforming a replacement drug entity into a pharmaceutical formulation in such how that it are often administered during a right way, in correct quantity , and on perhaps the foremost important at right target. The secondary objective preformulation study is to supply longer stability to the formulation by proper designing and protecting drug component from condition and to guage performance of developed formulation. The optimization of molecule is required with reference to stability of molecule under normal condition or with reference to enhancing the performance of that molecule like bioavailability and stability. To inbuilt these virtues into a molecule, efforts are made to optimize a molecule inform of salts, solvates, polymorphs, and more importantly prodrug. Converting a molecule into a salt form is probably the foremost widely used approach to significantly enhance the performance of a molecule. This improvement are often made in area such as; increased solubility and bioavailability i.e., performance of the drug, improved stability, taste masking properties, increased patient compliance and also modified drug release. Prodrug is that the chemically modified inactive derivative of active form with optimized properties and better in vivo performance. Almost one-tenth of the pharmaceutical products are used as prodrug with main aim of improving bioavailability by avoiding first-pass metabolism, improved drug absorption, and organ selective transport.

During the preformulation process, there are some studies like physicochemical parameters like organoleptic properties, bulk characterization studies, solubility analysis, stability analysis, play an important role during the preformulation processes even have a great impact on the drug release patterns.

After completion of preformulation evaluation of latest drug candidates, it's recommended that a comprehensive report be prepared highlighting the pharmaceutical problems related to molecules. It helps in developing phase I clinical trial formulations and in preparing regulatory documents and aid in developing subsequent drug candidates. If, drug is found satisfactory sufficient quantity is synthesized to perform initial toxicity studies, initial analytical work and initial preformulation. Once past initial toxicity, phase I clinical trial (clinical toxicology) begins for actual formulations. then phase II clinical trial and III clinical testing begins, and through this phase an order of magnitude formula is finalized. After completion of all above, an NDA is submitted and after approval of NDA, production can start.