Which of the following is a possible preformulation consideration to assess crystal forms?

• A. Existence of polymorphs
• B. Efficacy
• C. Toxicity
• D. In vivo testing

Answer: (A)

Understanding crystal forms is a preformulation concern because the solid-state form of a drug substance directly influences properties like solubility, dissolution rate, stability, and manufacturability. Polymorphism means the same molecule can crystallize into different structures, each with distinct physical properties. Recognizing whether polymorphs exist, which form is most stable under storage, and how easily interconversion can occur informs formulation strategy and quality control, helping predict how the drug will perform in the final product. Techniques such as X-ray powder diffraction and differential scanning calorimetry are used to detect and characterize polymorphs, and the chosen form can impact bioavailability due to solubility differences. Efficacy, toxicity, and in vivo testing relate to pharmacodynamics and clinical outcomes, not the crystal-form properties typically addressed in preformulation.