Hydration-activated drug delivery systems

Magnetics-activated drug delivery systems Sonophoresis-activated drug delivery systems Iontophoresis-activated drug delivery systems Hydration-activated drug delivery systems... 

Fig. 22 (A) Schematic illustration of Valrelease tablet, a swelling-activated drug-delivery system, and the hydration-induced formation of colloid gel barrier. (B) Comparison in the gastric residence profile between Valrelease with the conventional Valium capsule. (From Ref. l)...

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... 

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