Formulation development of BCS Class II and IV drugs is a challenging task due to their
poor solubility and permeability issue.
An extensive literature survey was conducted to explore the relevant pharmaceutical approaches that
have been used for solving the issue of poor solubility and permeability in the recent past.
It has been found that a plethora of approaches have been investigated for addressing the issue of poor
solubility and or permeability. These include physical modifications (modification of crystal habit, particle
size reduction, complexation, polymorphism and drug dispersion in carriers), chemical modifications
(salt formation), and formulation modifications (Nanotechnology-based approaches and hydrotropy).
The physical and chemical modification approaches can be effectively used to enhance the solubility
and dissolution rate of poorly soluble drugs, but the additional problem of poor permeability has been
better addressed by lipid-based drug delivery systems. As the latter presents the drug in the solubilized
state, bypass first-pass effects, circumvent the effect of Para-glycoprotein mediated efflux of drugs,
hence contributing to overall bioavailability enhancement.