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This Defense Intelligence Agency reference document, dated 7 January 2010 and prepared under the Acquisition Threat Support series, surveys biomaterials used in medicine. It covers biocompatibility, biosensor membranes, silicones, Teflon, biodegradable polymers, hydrogels, titanium, bioceramics, tissue constructs, cardiovascular stents, contact lenses, drug delivery and dialysis. It concludes that biomaterial performance underlies many medical devices, that the industry is slow to adopt new materials because of testing costs, and that innovation mainly involves new applications of established materials.
UNCLASSIFIED/;5P8R. 8PPIIH!ilct ~91! 9HLY the active agent in a biodegradable polymer, as shown in Figure 28. The polymer host to the drug dissolves, releasing the drug in a controlled manner over tlme. pulyn1er \ /drug time - O time - t Figure 26. Schematic Representation of Biodegradable (Bioerodible) Drug Delivery Device The use of biodegradable materials allows the drug to be introduced without much concern for the build-up of the polymer carrier. The carrier is eventually absorbed by the body and, thus, need not be removed surgically. Drug diffusion through the polymer matrix can also determine the drug dosage rate without actual loss of the polymer. This rate is determined by the choice of polymer, the size of its pores, and the rate at which the drug diffuses from the pores. The three key advantages polymeric drug delivery products can offer are: • Locallzed Delivery of Drugs: The polymer-drug combination can be implanted directly at the site where drug action is needed and, hence, whole-body exposure of the drug can be reduced. This becomes especially important for toxic drugs, such as the chemotherapeutic drugs. • Sustained Delivery of Drugs: Once injected, the encapsulated drug is released over extended periods, thereby eliminating the need for multiple injections. This feature can improve patient compliance, especially with drugs for chronic indications that require frequent injections (such as for deficiency of certain proteins). • Stabilization of the Drug: The polymer can protect the drug from the physiological environment and hence improve its stability in vivo. This particular feature makes this technology attractive for the delivery of labile drugs, such as proteins. 21 UNCLASSIFIED//FOR GFFltiilJtls. U81! 81t1L I
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Report, from the dia collection. The PDF is mirrored here; the original link is above. 32 pages are in the text index: search them above, or from the library's search.