Mechanical, water uptake and permeability properties of crosslinked chitosan glutamate and alginate films

Studies on diffusion in alginate gels. I. Effect of cross-linking with calcium or zinc ions on diffusion of acetaminophen

Mechanisms of external and internal gelation and their impact on the functions of alginate as a coat and delivery system

Effective treatment of infections in avascular and necrotic tissues can be challenging due to limited penetration into the target tissue and systemic toxicities. Controlled release polymer implants have the potential to achieve the high local concentrations needed while also minimizing systemic exposure. Silk biomaterials possess unique characteristics for antibiotic delivery including biocompatibility, tunable biodegradation, stabilizing effects, water-based processing and diverse material formats. We report on functional release of antibiotics spanning a range of chemical properties from different material formats of silk (films, microspheres, hydrogels, coatings). The release of penicillin and ampicillin from bulk-loaded silk films, drug-loaded silk microspheres suspended in silk hydrogels and bulk-loaded silk hydrogels was investigated and in vivo efficacy of ampicillin-releasing silk hydrogels was demonstrated in a murine infected wound model. Silk sponges with nanofilm coatings were loaded with gentamicin and cefazolin and release was sustained for 5 and 3 days, respectively. The capability of silk antibiotic carriers to sequester, stabilize and then release bioactive antibiotics represents a major advantage over implants and pumps based on liquid drug reservoirs where instability at room or body temperature is limiting. The present studies demonstrate that silk biomaterials represent a novel, customizable antibiotic platform for focal delivery of antibiotics using a range of material formats (injectable to implantable).

Antibiotic-Releasing Silk Biomaterials for Infection Prevention and Treatment.

The fluid bed encapsulation process consists of spraying a coating solution into a fluidized bed of solid particles. After several cycles of wetting–drying, a continuous film is formed. This paper provides an overview of the physical and transport phenomena involved in this process, especially in the so-called Wurster mode. Both qualitative and quantitative results are presented for several industrial applications. The main parameters affecting the process are flow-rate and pressure of the spraying liquid, composition and rheology of the coating solution, flow-rate and temperature of the fluidizing air. The particle size can range from 0.1 to several millimeters in equivalent diameter. The characteristics of the particle surface are important in determining adhesion of the liquid coating as well as its encapsulation properties.

H. Rupprecht

Papers

Film coating of pellets with insoluble polymers obtained in situ crosslinking in the fluidized bed