Drug delivery systems diffusion-controlled

Figure 4.1 Released amount Qt versus square-root-time -Jt plots. Illustration of loading less than or equal to saturation (dispersed, A < Cs) and greater than saturation (dissolved, A > Cs) in a matrix-type diffusion-controlled drug delivery system.

Figure 4.5 Transdermal diffusion-controlled drug delivery systems four design configurations and their basic elements.

Nondegradable subcutaneous implants as diffusion-controlled drug delivery systems, including Norplant, have been reviewed.89 99 Unlike biodegradable implants with long-term toxicological concern for metabolism of the polymer, nondegradable implants cannot avoid removal of the... 

Chapter 4. Diffusion-Controlled Drug Delivery Systems Puchun Liu,... 

Polymer matrix diffusion-controlled drug delivery systems. 

Siepmann J, Lecomte F, Bodmeier R. Diffusion-controlled drug delivery systems calculation of the required composition to achieve desired release profiles. / Control Release 1999 60(2-3) 379-389. 

Figure 2 Classification scheme for predominantly diffusion-controlled drug delivery systems. Only spherical dosage forms are illustrated, but the scheme is applicable to any type of geometry. Stars represent dissolved (individual) drug molecules, whereas black circles represent undissolved drug excess (e.g., crystals and/or amorphous aggregates).

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

Details are given of pilocarpine trapped in a matrix diffusion-controlled drug delivery system using hydrophilic inserts of polyhydroxyethyl methacrylate. The physical and chemical properties of pilocarpine were investigated to determine the mechanism of drug-polymer interaction and the effect of drug release behaviour of controlled release polymeric devices. 22 refs. 

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