Drug release wettability

Incorporation of surfactants in HPMC compressed matrices has been shown to cause retardation of drug release [110-112]. The first mechanism postulated was that anionic surfactants were capable of binding to nonionic polymers to increase the viscosity [110], More recently, drug-surfactant ionic interaction has been put forward instead, resulting in the formation of a complex with low solubility in water [111,112]. Note that such an effect can unintentionally occur upon putting some surfactant into the release medium in order to increase wettability. 

Wettability, surface roughness, air permeability, and ceU toxicity were measured. Also, the reproducibility of dosage was measured. The drug release rate decreases with increasing thickness of the coating film. The printed solid dosage forms showed an excellent imiformity with respect to content. 

The basic physical parameters of polymeric matrices prepared by simple physical mixing of drug and polymer powders are reviewed The wettability of the matrix, its pore structure and the permeability of the polymer particles resulted to be the controlling factors in the overall penetration process and in the subsequent drug release mechanism A simple experimental approach to the identification of the penetration mechanism is proposed, which allows to distinguish between a capillary driven penetration and a diffusion controlled permeation process ... 

The relevance of the pore structure on the drug release rate from porous matrices is shown in table 2 and figure 2m For a wettable polymer such as the acrylic, the reduction in total pore volume caused by any process,... 

We have previously discussed antibiotic-loaded cements produced by mixing the desired antibiotic with the PMMA cement. In this way, antibiotic elution and absorption are almost completely related to a surface phenomenon. Elution rates are dictated by several factors such as the porosity of the cement, surface area, wettability of the polymer, and the type and amount of antibiotic [1]. Increasing the porosity of the cement also increases drug elution [ 154]. A study by van de Belt et al. [83] showed that the initial release of gentamicin from an acrylic polymer matrix is partially a surface phenomenon, whereas the total amount released depends on bulk porosity. Therefore, a combination of surface roughness and porosity could improve the release kinetics of... 

Uses Excipient, vehicle, solubilizer for poorly water-sol. substances, dispersant, bioavailability enhancer for pharmaceuticals, esp. hard gelatin capsules, soft gelatin capsules, tablets, granules, controlled-release formulations Features Disperses rapidly in Gl tract, enhancing wettability of the drug crystallizes rapidly a few degrees below m.p. inert Properties Solid water-sol. vise. 60 mPa S (60 C) m.p. 44 C HLB 14 Akomed E [AarhusKarlshamn AB]... 

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