A Systematic Review of Solubility Enhancement Techniques Used for BCS Class II & IV

Because of their low solubility, pharmaceutical researchers encounter tremendous difficulties in creating sustainable and more soluble drugs (BCS class II). About 40% of oral dosage forms have formulation and development problems due to water insolubility. The rate of dissolving, absorption, distribution, and excretion of an active medicinal substance is determined by its solubility parameters. Based on their solubility, drugs are divided into four kinds under the BCS categorization system. BCS Class II and Class IV drugs have problems with solubility. Increasing both the bioavailability and the solubility of poorly soluble medications can be accomplished in several ways. Some techniques—like solid dispersion, solid complexation, liquisolid, hydrotropy, sonocrystallization, and self-emulsifying techniques—are commonly used for solubility augmentation. Until an orally active medication dissolves in the lining of the stomach and/or intestinal fluids, it cannot pass through the GI tract membrane and enter the bloodstream. Therefore, a medication that is insoluble in water will typically exhibit limited absorption by dissolution, and a medication that is weakly permeabilized via membranes would typically exhibit limited absorption through permeation. Consequently, improving the oral bioavailability of active substances is the focus of two areas of pharmaceutical research: (i) accelerating the process of dissolution and solubility of drugs that are poorly soluble in water, and (ii) accelerating the permeability of poorly permeable drugs.