Hydrotropy: A Promising Tool for Solubility Enhancement

Abstract

Solubility is one of the key parameters to attain desired concentration of drug in systemic circulation to show pharmacological response. Various methods are engaged to augment the aqueous solubility of poorly water-soluble drugs and hydrotropic solubilisation is one of them. Hydrotropy is defined as a solubilization process whereby addition of a large amount of second solutes results in an increase in the aqueous solubility of another solute and chemicals which are used in the hydrotropy are called hydrotropes like sodium benzoate, sodium citrate, urea, niacinamide etc. Based on advantages like the high selectivity, independent of pH and cheap, easy availability makes this technique more prevailing than other solubilisation methods. Mixed hydrotropy is a solubilisation technique to augment the water solubility of poorly water soluble drugs by the way of different ratio of blends of hydrotropic agents which gives synergistic augmentation effect. The purpose of this review article is to illustrate the need for solubility, hydrotropic solubilisation, mechanism of action of hydrotrope, classification of hydrotropes, advantages and mixed hydrotropic technique of solubilisation for improving the solubility which in turn helps to attain absorption and improved bioavailability.