Swelling-controlled drug delivery systems

P Colombo, R Bettini, P Santi, A De Ascentiis, NA Peppas. Analysis of the swelling and release mechanisms from drug delivery systems with emphasis on drug solubility and water transport. J Controlled Release 39 231-237, 1996. 

The amphiphilic nature of the polyester/PHEMA networks provides gels able to swell in both organic and aqueous media, which prompted us to study them as controlled drug delivery systems [114]. The most valuable characteristic feature of these amphiphilic networks is their potential to sustain the drug delivery... 

Figure 6.4. Swelling-induced time-controlled drug delivery systems.

Figure 18.13 Diffusion controlled drug delivery systems, (A) Matrix is unswelling device, (B) Matrix is a swelling controlled one.

Swelling is one of the functional properties used to characterize biopolymers required for modified or controlled drug delivery systems. The biopolymers employed for modified drug delivery applications are hydrogels that form three-dimensional polymeric networks when they come into contact with water, they absorb many times their weight of water but they do not dissolve. Swelling of the ceUulosics in different biorelevant media must be established. 

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