Enhancement of solubilization and bioavailability of poorly soluble drugs by physical and chemical modifications: A recent review

The aim of this review was to improve the solubility and bioavailability of poorly soluble drugs by using various approaches like physical, chemical and others modifications or techniques. 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. Drug efficacy can be severely limited by poor aqueous solubility and some drugs also show side effects due to their poor solubility. There are many techniques which are used to enhance the aqueous solubility. The ability to increase aqueous solubility can thus be a valuable aid to increasing efficiency and/or reducing side effects for certain drugs. This is true for parenterally, topically and orally administered solutions. Physical modifications techniques like media milling/ nanocrystal technology, cryogenic technology, supercritical fluid process, modification of the crystal habit,complexation, micellar technologies, chemical modifications, other techniques like co-crystallization, Co-solvency, hydrotrophy are used for increase the solubility of very soluble drugs like dolargin, loperamide, tubocurarine, doxorubicin, ibuprofen, griseofulvin, diazepam, naproxen, carbamazepine, nifedipine, phytosterol etc.