Solubility enhancement (Solid Dispersions) novel boon to increase bioavailability

Abstract

The solubility of a solute is the maximum quantity of solute that can dissolve in a certain quantity of solvent or quantity of solution at a specified temperature. Solubility is one of the important parameter to achieve desired concentration of drug in systemic circulation for pharmacological response to be shown. Solubility is essential for the therapeutic effectiveness of the drug, independent of the route of administration. Low aqueous solubility is the major problem encountered with formulation development of new chemical entities as well as for the generic development. Poorly soluble drugs are often a challenging task for formulators in the industry Conventional  approaches  for  enhancement  of  solubility  have  limited  applicability,  especially when  the  drugs  are  poorly  soluble  simultaneously  in  aqueous  and  in  non-aqueous  media. Drug with poor water solubility cause slow dissolution rates, generally show erratic and incomplete absorption leading to low bioavailability when administered orally. Solubilization may be affected by cosolvent water  interaction, micellar solubilization, reduction in  particle  size,  inclusion  complexes,  solid  dispersion,  and  change  in  polymorph.  Some  new technologies  are  also  available  to  increase  the  solubility  like  micro emulsion,  self-emulsifying drug  delivery  system  and  supercritical  fluid  technology. This present review details about the different approaches used for the enhancement of the solubility of poorly water-soluble drugs include particle size reduction, nanonization, pH adjustment, solid dispersion, complexation, co‐solvency, hydrotropy etc. The purpose of this article is to describe the techniques of solubilization for the attainment of effective absorption and improved bioavailability. Keywords: Solubility, Solubility Enhancement, bioavailability, solid dispersion, Solid Dispersion, Solubilization.