Alternative Technologies to Improve Solubility and Stability of Poorly Water-Soluble Drugs
The solubility behavior of drugs remains one of the most challenging aspects in formulation development. Solid dispersions (SD) and inclusion complexes (IC) are two of the most promising strategies to improve the oral bioavailability of poorly water-soluble drugs. Cyclodextrins (CDs) are cyclic carbohydrates of natural origin with a hydrophobic cavity and hydrophilic exterior. This characteristic enables the formation of water-soluble inclusion complexes (ICs) with a large variety of molecules of low solubility. The term solid dispersion has been used to describe a family of dosage forms whereby the drug is dispersed in a biologically inert matrix (for example, polymers), usually with a view to enhancing oral bioavailability. The combination of these systems leads to the formation of what we call ternary complexes, also called systems or multicomponent complexes. This combination has been of great interest to the scientific and technical community, because of the physical, chemical, and biological properties of drugs that can thereby be optimized, although the use of polymers in ternary systems can both increase and reduce their complexation.