Solubility is the phenomenon of dissolution of solid in liquid phase to give a homogenous system.Solubility is one of the important parameter to achieve desired concentration of drug in systemic circulation for pharmacological response to be shown. Poor watersolubledrugs often require high doses in order to reach therapeutic plasma concentrations after oral administration. Low aqueoussolubility is the major problem encountered with formulation development of new chemical entities. Any drug to be absorbed must be present in the form of an aqueous solution at the site of absorption. Water is the solvent of choice for liquid pharmaceuticalformulations. Mostof drugs weakly acidic and weakly basic with poor aqueous solubility. Hence various …show more content…
Solubility is not to be confused with the ability to dissolve or liquefy a substance, since this process may occur not only because of dissolution but also because of a chemical reaction. Low aqueous solubility is the major problem encountered with formulation development of new chemical entities as well as for the generic development . The purpose of this review article is to describe the techniques of solubilizaton for the attainment of effective absorption and improved bioavailability.
Keywords: Solubility, solubility enhancement, co-solvent, pH, emulsions
A number of methodologies can be adapted to improve solubilization of poor water soluble drug and further to improve its bioavailability. The techniques generally employed for solubilization of drug includes micronization, chemical modification, pH adjustment, solid dispersion, complexation, co‐solvency, …show more content…
Very high drug concentrations of poorly soluble compounds can be dissolved compared to other solubilization approaches. However, the bioavailability may not be dramatically increased because the poorly soluble drug will typically uncontrollably crash out upon dilution into a crystalline or amorphous precipitate. In this case, dissolution of this precipitate is required for oral absorption. Co-solvents may be combined with other solubilization techniques and pH adjustment to further increase solubility of poorly soluble compounds. The use of co-solvents is a highly effective technique to enhance the solubility of poorlysoluble drugs.14–16
The most frequently used low toxicity co-solvents for parenteral use are propylene glycol, ethanol, glycerin, and polyethylene glycol.17-18
Dimethylsulfoxide (DMSO) and dimethylacetoamide (DMA) have been widely used as cosolvents because of their large solubilization capacity for poorly soluble drugs and their relatively low toxicity.19-21
Simple and rapid to formulate and