Which statement is true regarding the solubility of amorphous and crystalline forms of an API?

The statement that the amorphous form has lower stability and higher solubility is accurate. Amorphous forms of active pharmaceutical ingredients (APIs) typically have higher solubility compared to their crystalline counterparts. This is primarily due to their disordered structure, which allows for more interaction with solvents, leading to an increased dissolution rate.

In contrast, the crystalline form is more stable due to its ordered molecular structure, which makes it less prone to changes under varying environmental conditions. However, this stability comes at the cost of decreased solubility. The defined lattice in crystalline substances requires more energy to break apart, making it harder for the molecules to enter solution compared to the more freely arranged molecules found in amorphous forms.

Understanding this relationship is crucial in pharmaceutical development, particularly when considering bioavailability and the overall effectiveness of an API. Thus, the accurate characterization of solubility properties between amorphous and crystalline states is essential for the formulation of effective drug delivery systems.