Influence of Disorder on Dissolution

This chapter focuses on some of the approaches to enhance drug solubility, with the ultimate goal of enhancing oral bioavailability of poorly water soluble drugs. In order to estimate the dissolution advantage offered by the amorphous form, the solubility advantage should be first assessed. Solid dispersions are a promising strategy to overcome the physical instability associated with amorphous compounds. Polymer structure, including the nature and number of hydrophilic and hydrophobic functional groups, backbone rigidity, and molecular weight have been found to influence the extent and duration of drug supersaturation. Drug-polymer interaction in solution is one of the mechanisms for facilitating the maintenance of drug supersaturation. For a given drug-polymer system, with an increase in polymer concentration, drug supersaturation in solution can be maintained for a longer duration. The stabilization is attributed to an increase in solution viscosity.