It has been well explained that solubility

It has been well explained that solubility, dissolution and gastrointestinal permeability are fundamental parameters that control rate and extent of drug absorption and bioavailability.1 The water solubility of a drug is a fundamental property that plays an important role in the absorption of the drug after oral administration. The drug solubility is an equilibrium measure but also the dissolution rate at which the solid drug or drug from the dosage form passes into solution is critically important when the dissolution time is limited.2 Although the oral bioavailability of a drug depends on aqueous solubility, drug permeability, dissolution rate, first-pass metabolism and susceptibility to efflux mechanisms, aqueous solubility, and drug permeability are also important parameters attributed to oral bioavailability.3 In drug discovery, the number of insoluble drug candidates has increased in recent years, with almost 70% of new drug candidates showing poor water solubility.4 For these drug candidates, poor aqueous solubility and poor dissolution in the GI fluids is a limiting factor to the in-vivo bioavailability after oral administration. Therefore, in-vitro dissolution has been recognized as an important element in drug development and thus increasing the dissolution rate of poorly soluble drugs and enhancing their bioavailability is an important challenge for pharmaceutical scientists.5, 6