Drug delivery systems actuated polymers

Superabsorbents are superabsorbent polymers, which are loosely crosslinked hydrophilic polymers and have ionic charges in the polymers. They absorb water, swell, and retain aqueous solution above hundred times their own weight. Because of the excellent characteristics, the superabsorbents have been widely used in many applications such as disposable diapers, feminine napkins, soil additives in agricultural or horticultural applications, gel actuators, water-blocking tapes, materials for drug delivery system, absorbent pads, etc., where water absorbency or water retention is important. 

As PSi-polymer composites exhibit unique properties that are culminated by the characteristics of each building block, they can be rationally designed to display highly tunable properties, e.g., mechanical, chemical, optical, and electrical. Over the past decade, these attractive nanocomposites have been studied as platforms for designing different devices. Applications of these composites range from drug delivery systems, sensors, and actuators to optoelectronics and photovoltaics. 

For other routes of delivery, the formulation considerations relating to polymers are less restrictive than for the parenteral route. Typically, for local rather than systemic activity, polymers can be used to enhance efficacy of topical drug delivery systems through solubility enhancement and or skin hydration. For transdermal delivery, polymers can have several roles, either as solubility modifiers, permeation enhancers or as aids in iontophoresis. The presence of multiple-charged species is a prerequisite for iontophoretic movement of drag molecules through the skin, so can be considered as an actuation process... 

Both miniaturized analyte sensors and microsystems for drug delivery have been demonstrated, and the integration of both functionalities within one medical device is the next natural step. Smart polymer-based sensors, actuators, microvalves, micropumps, etc., can be combined in a single microfluidic system to construct medical devices with applications in diagnostics and/or treatment, and first attempts at developing such LOC devices are currently underway. 

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