Table I.

Classification of Drugs Based on Their Glass Formation Ability (Adapted from (33))

Class		Behaviora	Examples
Class 1	A	Always crystallize on cooling	Atenolol, felbinac
	B	Amorphous on quench cooling	Griseofulvin, carbamazepine
Class 2		Cooling—no crystallization; heating—crystallization	Acetaminophen, cinnarizine
Class 3		Cooling and heating—no crystallization	Piroxicam, ketoconazole, indomethacin, ursodiol

^aCooled at 20°C/min, heated at 10°C/min in a DSC