Microsphere in Herbal Drug Delivery System

Abstract

Microspheres constitute an important part of these particulate drug delivery systems by virtue of their small size and efficient carrier capacity. The success of these microspheres is limited due to their short residence time at site of absorption. It would, therefore be advantageous to have means for providing an intimate contact of the drug delivery system with the absorbing membrane. Microspheres are characteristically free flowing powders consisting of proteins or synthetic polymers which are biodegradable in nature and ideally having a particle size less than 200 μm.The oral route of drug administration constitutes the most convenient and preferred means of drug delivery to systemic circulation of body. This can be achieved by coupling bioadhesion characteristics to microspheres and developing bioadhesive microspheres. Bioadhesive microspheres have advantages like efficient absorption and enhanced bioavailability of the drugs due to a high surface to volume ratio, a much more intimate contact with the mucus layer and specific targeting of drugs to the absorption site. Polyethylene microspheres are commonly used as permanent or temporary filler. Lower melting temperature enables polyethylene microspheres to create porous structures in ceramics and other materials. High sphericity of polyethylene microspheres, as well as availability of colored and fluorescent microspheres, makes them highly desirable for flow visualization and fluid flow analysis, microscopy techniques, health sciences process troubleshooting and numerous research applications. Charged polyethylene microspheres are also used in electronic paper digital displays. Microspheres may be coated with Capture molecules, such as antibodies, oligonucleotides, peptides, etc. for use in Diagnostic or separation applications. Microsphere coatings are typically optimized to achieve desired specific activity, while minimizing nonspecific interactions. Consideration should also be given to the required stability, development time frame And budget, and the specific bimolecular to be coated. These factors will aid in determining the most fitting coating strategy for both short- and long-term objectives. Standard microsphere products support three basic coating strategies: adsorption, covalent coupling, and affinity binding. Better drug utilization will improve the bioavailability and reduce the incidence or intensity of adverse effects.