Drug-protein binding studies new trends in analytical and experimental methodology

Field-flow fractionation (FFF) is a family of flexible elution techniques capable of simultaneous separation and measurement. Its sample domain extends across a broad macromolecular-colloidal-particulate continuum from about 1 nanometer to more than 100 micrometers and incorporates both simple and complex macromaterials of biological, biomedical, industrial, and environmental relevance. Complex materials are separated into components to simplify measurement. Component properties measurable by FFF include mass, size, density, charge, diffusivity, and thickness of adsorbed layers. When characterization by these properties is inadequate, other measurement tools can be readily coupled to FFF, either off-line or on-line, by virtue of its flow-elution operation. This article describes the principles and major subtechniques of the FFF family along with application of its measurement and separative capabilities.

This article re-examines the issue of salivary therapeutic drug monitoring (STDM). The anatomy and physiology of saliva and the salivary glands, as well as the effects of disease and drugs on salivary secretion and composition, are discussed briefly. Drugs for which therapeutic drug monitoring (TDM) has been shown useful are individually considered to determine if salivary drug concentrations (Csal) are reflective of plasma free drug concentrations (C(up)). That is, is the Csal/C(up) ratio time- and concentration-independent, as supported by a review of literature data? The primary determinant which appears to govern the potential utility of STDM for many of the drugs is the pKa of the drug. Drugs which are not ionisable or are un-ionised within the salivary pH range (phenytoin, carbamazepine, theophylline) are candidates for STDM based on current literature data. Digoxin and cyclosporin are potential candidates for STDM; however, further studies are necessary to confirm these preliminary findings. On the basis of current literature data, STDM does not appear to be useful for other drugs therapeutically monitored in serum/plasma.