Filled Elastomers Drug Delivery Systems

The theoretical understanding of filled elastomers has been improved to the extent that now a connection can be made between the filler structures on larger length scales and the viscoelastic properties of rubbery materials.

Drug delivery systems have taken a great impetus to deliver a drug to the diseased lesions. Although this concept is not new great progress has recently been made in the treatment of a variety of diseases. A suitable carrier is needed to deliver a suitable and sufficient amount of the drug to a targeted point, hence, various kinds of formulations are being constantly developed. This paper reviews the present state of art regarding the synthetic methods and characterization of nanoparticles, the suitability of polymeric systems for various drugs, drug loading and drug release properties of various systems such as nanoparticles, hydrogels, microspheres, film and membranes, tablets, etc. The purpose of this review is to summarize the available information so that it will be helpful to beginners and serve as a useful tool for active researchers involved in this area.

The use of polymeric nanoparticles as drug carriers is receiving an increasing amount of attention both in academia and industry. The development of suitable delivery systems for protein drugs with high molecular weights and short half-lives is of current interest. In addition, nanoparticles have a number of potential applications in drug and vaccine delivery as well as gene therapy applications. This article features a new production technology for nanoparticles comprised of multicomponent polymeric complexes that are candidates for delivery vehicles of biological molecules such as proteins and drugs. Materials science theory and practice provide the basis for the development of highly compacted structures that are insoluble in water and buffered media. Biocompatible and mostly natural polymers are fabricated into thermodynamically stable nanoparticles, in the absence of organic solvents, using two types of processing: batch and continuous. Careful choice of construction materials and the superposition of several interacting principles during their production allow for the customization of the physicochemical properties of the structures. Among the typical polymers used to assemble nanoparticles, different polysaccharides, natural amines and polyamines were investigated. The entrapped substances tested included proteins, antigens and small drug molecules. The size and charge of nanoparticles is considered to be of primary importance for application in biological systems. Detailed experiments in batch and continuous systems allowed time-dependent stoichiometric characterization of the production process and an understanding of fundamental assembly principles of such supramolecular structures. Continuous-flow production is shown to provide more consistent data in terms of product quality and consistency, with further possibilities of process development and commercialization. To control permeability, polydextran aldehyde, incorporated into the particle core, was used to enable physiologic cross-linking and long-term retention of substances that would otherwise rapidly leak out of the nanoparticles. Results of cross-linking experiments clearly demonstrated that the release rate could be substantially reduced, depending on the degree of cross-linking. For vaccine antigen delivery tests we measured an antibody production following subcutaneous and oral administration. The data indicated that only the cross-linked antigen was immunogenic when the oral route of administration was used. The data presented in this paper address primarily the utility of nanoparticulates for oral delivery of vaccine antigen. This novel technology is extensively discussed in contrast to other technologies, primarily water- and organic solvent-based. The usefulness is demonstrated using several examples, evaluating protein and small drug delivery.