Conventional drug delivery in the form of tablets, liquids and vaccines have a common limitation in their release profile because they experience an initial burst followed by exponential decay. This type of release profile creates side effects and requires several doses because the initial burst causes rapid removal of the released molecule by the body. Controlled release of molecules from various delivery systems, tablets, microspheres, polymer matrices, implants, hydrogels, films, etc., have gained popularity in recent years as a method of overcoming this limitation.Off line spectroscopy and chromatographic methods are the primary techniques use by researchers for determining release profiles of delivery systems. Normally the delivery system is placed in flasks containing the desired solution. The flask can then be stirred, shaken, heated or left completely static. At specific intervals a sample is removed for spectroscopic analysis in order to determine the concentration of the molecule being released. Problems commonly encountered with this method include; non-real-time release analysis, limited sample size, and difficulty simulating physiological flow and environment conditions.Simulation of flow conditions can be important to the delivery system release profiles. It is desirable to replace offline monitoring with a system that can dynamically monitor release/adsorption of molecules online requiring no sample removal. It is further desirable that the system accommodate a wide variety of releasing/adsorbing components and flow cell-based online detection modalities.With this in mind, researchers at Arizona State University have developed a modular online release/adsorption system that can dynamically measure changes in concentrations of molecules that are released into- or adsorbed from the liquid phase. The system is configured such that various releasing/adsorbing components and detection assemblies can be easily connected for a wide variety of online analysis methodologies. The flow system is especially useful for in vitro dynamic monitoring of molecules released from- or adsorbed onto solid and semi-solid materials from a contacting liquid phase containing dissolved molecules.
|Original language||English (US)|
|State||Published - Jan 1 1900|