APPLICATION OF MODERN ELECTROANALYTICAL TECHNIQUES: RECENT TREND IN PHARMACEUTICAL AND DRUG ANALYSIS

The determination of drugs in pharmaceutical preparations and biological fluids is of pivotal importance in the pharmaceutical and medical sciences. Successful analysis requires sensitivities at ppb level or even less in biological fluids with high selectivity and minimal interferences from various artifacts. Till recently, biopharmaceutical analysis relied principally on spectrophotometric assay, chromatographic methods including gas-liquid chromatography (GC), high performance liquid chromatography (HPLC),  GC-mass spectrometry (GS-MS), LC-MS-MS, enzyme-linked immunosorbent assay (ELISA), radioimmunoassay (RIA) and related techniques. Recent trends in drug analysis are the use of electrochemical detectors coupled with LC or flow injection systems. With the considerable progress in analytical instrumentation, modern electrochemical methods are gaining popularity in determination of therapeutic agents and/or their metabolites in clinical samples at extremely low concentrations (10-50 ng/ml) and yet they are highly sensitive, robust and inexpensive. The electrochemical detection offers extreme selectivity as fewer electroactive interferents and moreover, only very small volume of biological sample is needed. The present review provides comprehensive information on the literature on the application of modern electrochemical methods for pharmaceutical and drug analysis in the last two decades. The principles and theories of various modern electrochemical techniques as well as recent advancements with regard to instrumentation  involving electrode surface modifications namely amperometric, nanotubes based biosensors, polymer-modified, ion selective electrodes and modified indium-tin-oxide (ITO) electrodes for the determination of drugs in pharmaceutical preparations and biological fluids are also included.