Ionic liquids: Pharmaceutical and Biotechnological Applications

Ionic liquids (ILs) are largely made of ions and short-lived ion pairs. These often possess a unique combination of physical and chemical properties which are not available with molecular solvents. ILs are dynamic, attractive and rich research area and are gaining considerable attention as promising molten materials for a variety of applications in pharmaceutical and biotechnology fields. Ionic liquids provide an alternative to certain solvents in select reactions used to synthesize intermediates and active pharmaceutical ingredients. Determination of enantiomeric compositions of pharmaceutical products has been achieved in ILs. The use of ILs include i) avoid polymorphism of crystalline solids, ii) stabilizes labile biopharmaceutical products for therapeutic use, iii) converts active pharmaceutical ingredients to liquids with benign counter-ion, and iv) as antibiofilm agents. A huge potential for use of ionic liquids as preferred solvent system for synthesis and stabilization of nanoparticles and drug delivery technologies/development of new controlled-release dosage forms has been reported. Enzymes showed enhanced enantioselectivity without losing any significant activity upon coating with an ionic liquid. Ionic liquids showed great promise as a host to biomass fractionation. Use of the chiral ionic liquids in the pharmaceutical sector could help companies develop improved methods for synthesis of chiral products or the manufacture of single enantiomer drugs for the pharmaceutical industry. Ionic liquids have the potential to become an important part of the drug development tool-kitparticulary for biocatalysis, mass extraction and vessel cleaning. By acting as a reactant/product reservoir, hydrophobic Ionic Liquids can assist in biotransformations carried out under biphasic operating conditions. ILs are toxicologically benign and thus their toxicity does not preclude their use as pharmaceutical solvents. Experts are of the opinion that Ionic liquid technologies are certain to broaden in pharmaceutical and biotechnological area in the coming years. INTRODUCTION liquids is no longer exclusive to academic laboratories. Researchers demonstrated that there “The pharmaceutical industries are have been parallel and collaborative exchanges undoubtedly experiencing a series of challenges. between academic research and industrial One of these is the administration of solid form of developments since the materials were first many drugs due to many well known drawbacks [3] reported in 1914 . Researchers are of opinion that including low solubility, polymorphic conversion ILs technologies are certain to broaden in and low bioavailability. Such problems are further pharmaceutical area in the coming years. aggravated when drug molecules or starting Extensive work has been carried out in the materials for synthesis of drugs are insoluble or past few years with the hope that the ionic nature of sparingly soluble in aqueous media and most of [1] ionic liquids would drastically change speed and pharmaceutical acceptable organic solvents” . To [4] selectivity of a variety of chemical reactions . The overcome these problems, ionic liquids (ILs) have key properties that set ionic liquids apart from other been increasingly exploited as solvents and/or liquids include the following: Existing as molten (co)solvents and/or reagents in a wide range of salts, in many cases even below room temperature, pharmaceutical applications due to their tailorhighly polar, often immiscible with organic made chemical, physical and biological properties. solvents, literally no vapour pressure, nonIls are a novel class of low temperature o flammable, large liquidus range (typically > 300 °C (typically<100 C) molten salts, comprised of [2]. grade), electrically conducting, remarkable discrete cations and anions Many are liquid at [5-7] dissolution properties and high thermostability . room temperature. Experts say that the use of ionic Publication History Received :8 Mar 2011 Accepted : 12 Jul 2011 Published : 10 Sep 2011