1. Obtain the relevant physical and chemical parameters of drugs, including physical properties, melting point, boiling point, solubility, dissolution, polymorph, pKa, partition coefficient, chemical properties, etc.

2. Determine its pharmacokinetic characteristics, such as half-life, elimination rate constant, absorption, metabolism and plasma concentration.

3. Determine the physical and chemical properties related to the prescription, such as powder properties, liquid rheological properties, surface properties, etc.

4. Determine the interaction between drugs and excipients, and the influence of excipients on the solubility and stability of drugs.

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The purpose of pre-prescription research is to provide basis for prescription process design and provide targeted solutions for problems in prescription process research. The quality characteristics of the final product of the preparation are largely determined by the properties of the API: although there are many methods to improve the quality characteristics and process reliability of the preparation, the effectiveness of these methods is often not as good as that of controlling the characteristics of the API. The development trend of modern products is that the control point moves forward. In the requirements of QbD research and development, another important purpose of pre-prescription research is to provide basis for preliminary risk assessment of preparation research and determine the direction and scope of preparation research.