Drug delivery systems biocompatibility

Skeletal Biocompatibility. Two Substituent Groups Attached to the Same Phosphazene Skeleton. Hydrolytical Instability 0 II — NH- CH2— C- OC2H5 Glycine or Lower Alkyl Aminoacid Esters Hydrolytically Unstable Polymers. Bioerodible Materials. Drug Delivery Systems. Tissue Engineering... 

In this chapter an overview of both the opportunities and the problems presented by the biological system for the use of polymeric drug delivery systems will be presented. Since the area of biocompatibility of the delivery system is a well-known constraint also imposed by the biological system and is beyond the scope of this presentation, this (important) consideration will be ignored here. In order to examine how a delivery system interacts with the biological system to... 

New drug delivery systems are of great scientific and commercial interest. Amphiphilic networks composed of about 50/50 hydrophobic PIB and hydrophilic poly(2-(-dimethylamino)ethyl methacrylate) (DMAEMA) polymer segments were found to be biocompatible and to a large extent avascular (7). These PHM-PDMAEMA networks (i, in line with propositions of Weber and Stadler (2), and Sperling (J), denotes PDMAEMA chains linked by PIB chains) gave pH dependent... 

However, the choice of a class of polymer for use in a given drug delivery system is often made for reasons unrelated to its swelling properties the polymer might be chosen on the basis of cost, availability, supplier, biocompatibility, past use history, etc. Thus the hydrophilicity and % will be fixed, and only the crosslink density and the ionic component can be readily adjusted to provide the swell-... 

Despite the evidence for the cytotoxicity of CNTs, there are an increasing number of published studies that support the potential development of CNT-based biomaterials for tissue regeneration (e.g., neuronal substrates [143] and orthopedic materials [154—156]), cancer treatment [157], and drug/vaccine delivery systems [158, 159]. Most of these applications will involve the implantation and/or administration of such materials into patients as for any therapeutic or diagnostic agent used, the toxic potential of the CNTs must be evaluated in relation to their potential benefits [160]. For this reason, detailed investigations of the interactions between CNTs/CNT-based implants and various cell types have been carried out [154, 155, 161]. A comprehensive description of such results, however, is beyond the scope of this chapter. Extensive reviews on the biocompatibility of implantable CNT composite materials [21, 143, 162] and of CNT drug-delivery systems [162] are available. 

Schiraldi et al. [64] have developed this kind of material by combining silica particles and pHEMA. pHEMA is a biocompatible hydrogel that has been widely studied in the past decades due to its chemical-physical structure and mechanical properties. It has been widely used in ophthalmic prostheses (contact or intraocular lenses), vascular prostheses, drug delivery systems and soft-tissue replacement [65]. These authors have shown that by incorporating silica nanoparticles, the resulting hybrid material is highly biocompatible and promotes bone cell adhesion and proliferation of bone cells seeded on it.1 ... 

Compared to classical drug delivery systems such as liposomes or peptides, nanotubes have a higher efficiency [41] and this can be used for the further development of delivery systems. Stability and diversity of nanotube forms provide long time circulation and biocompatibility that result in more efficient transport of substances. 

Silicon micropumps offer major advantages in terms of system miniaturization and control over low flow rates with a stroke volume 160 nL.14 The micropump has the characteristics of very small in size, implantability in the human body, low flow rates (in the range of 10 pL/min), moderate pressure generation from the microactuator to move the drug, biocompatibility, and most important, a reliable design for safe operation. The implantable device is particularly suitable (over the injectable drug delivery systems) for patients with Parkinson s disease, Alzhiemer s disease, diabetes, and cancer, as well as chronically ill patients, because the catheter that is attached to the device can transport drug to the required site. 

The polymer exhibits good biocompatibility, inertness, physical stability, and ease of processability. PEVAc containing 30 to 50% wt vinyl acetate content is used for drug delivery systems. 

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