USP <1236>: Solubility Measurements Chapter

USP Chapter <1236> provides a helpful overview of the theory and concepts behind solubility experiments. It also describes factors such as pH, salts and counter ions that potentially affect solubility and solubility measurements.


It summarises some experimental methods that can be used for determining equilibrium and apparent solubility of a drug substance. It also introduces in vitro solubility tests in select biorelevant media for humans, preclinical (canine) and some veterinary species.