Analytical method validation for HPLC assay of oral anticancer drug exemestane

Exemestane (EXE) is an irreversible aromatase inactivator used for the treatment of postmenopausal women with advanced breast cancer. EXE is practically insoluble in water and its bioavailability is approximately 5%. It is known that cyclodextrin (CD) complexation can enhance water solubility and intestinal permeability and thus the oral bioavailability of poorly soluble drugs. Therefore, it was aimed to design and develop CD complexes containing EXE to improve the aqueous solubility and increase the intestinal permeation in order to enhance the oral bioavailability. In this study, an analytical method developed by Yu et al. was validated to determine the amount of soluble EXE in phase solubility studies and in vitro dissolution studies of EXE. An HPLC method with UV detection was validated in methanol medium, using a Hichrom Nucleosil 100 C18 column (150mmx4.6mm). EXE peak area was linear (r² > 0.9996) over the concentration range 2.5 - 50 μg/mL. This validation included specificity, range, linearity, precision, accuracy, LOD and LOQ; all results were acceptable and confirmed that the method is suitable for its intended use.