Polymorphism 101: What Early-Stage Drug Developers Need To Know To Reduce Risk

By Steven Johnston, Ph.D., Senior Director of Pharmaceutical Development at Pace® Life Sciences

Polymorphism plays a critical role in small molecule drug development, influencing key properties that determine a product’s performance and success. Different crystal forms of the same compound can exhibit significant variations in solubility, stability, and bioavailability, directly impacting both clinical outcomes and manufacturability. Left unaddressed, these differences can lead to unexpected form changes during development, creating risks for scale-up, storage, and regulatory approval. Beyond traditional crystal forms, the broader solid-state landscape includes hydrates, solvates, salts, co-crystals, and amorphous materials, each with its own implications for drug performance. Early and systematic screening helps uncover these variations, enabling informed decision-making and more robust development strategies. By understanding polymorphism early, development teams can reduce costly surprises, ensure consistent product quality, and better position their programs for successful advancement.