General Introduction

Many new chemical entities are developed as oral solid form drugs such as tablets and capsules due to their patient-friendliness.1,2 An oral medication must be absorbed from the intestine in order to be effective, and high intrinsic activity against a target molecule would be useless if a large fraction of the administered drug is excreted without absorption.26 The rate and extent of oral absorption of a drug are predominantly controlled by its physicochemical properties.2,45. Poorly water-soluble drugs cannot dissolve completely in the intestinal tract within normal transit time and thus show poor oral bioavailability.5,6 Insufficient drug absorption results in decreased drug efficacy and incomplete evaluation of safety profiles in preclinical and clinical studies.4,6 In recent years, the number of poorly soluble drug candidates has been increasing.1,710 Therefore, improving their aqueous solubility is currently one of the major challenges in drug discovery and development.