Nanopolymers in drug delivery system

Abstract

Polymers have played an integral role in the advancement of drug delivery technology by providing controlled release of therapeutic agents in constant doses over long periods, cyclic dosage, and tunable release of both hydrophilic and hydrophobic drugs. Among the synthetic and biodegradable polymers, aliphatic polyesters such as poly (glycolic acid), poly (lactic acid), poly (caprolactone) and polydioxanone, are most commonly used and applied to drug delivery systems. The use of biodegradable polymeric nanoparticles (NPs) for controlled drug delivery has shown significant therapeutic potential. In cancer, targeted polymeric NPs can be used to deliver chemotherapies to tumor cells with greater efficacy and reduced cytotoxicity on peripheral healthy tissues. Through the manipulation of size, surface characteristics and material used, the nanoparticles can be developed into smart systems, encasing therapeutic and imaging agents as well as bearing stealth property. Further, these systems can deliver drug to specific tissues and provide controlled release therapy. Several nanotechnologies, mostly based on nanoparticles, can facilitate drug delivery to tumors like Hydrogels, Micelles and liposomes, Nanomaterial formulation, Nanosystems, Nanocells, Dendrimers, Nanotubes, etc. The larger the size of the drug, the more tumor penetration becomes a fundamental limitation. Lack of drug penetration becomes even more significant when using nanoparticles, as their perivascular accumulation and slow release pose a severe hindrance to drug delivery. The key advantages of nanoparticles are (1) improved bioavailability by enhancing aqueous solubility, (2) increasing resistance time in the body (increasing half life for clearance/increasing specificity for its cognate receptors and (3) targeting drug to specific location in the body (its site of action). Most important advantages offered by the polymeric nanoparticles include the following: (1) provide controlled release to the desired site, (2) provide stability to labile molecules (e.g., proteins), and (3) provide ability to modify surfaces with ligands for stealth and targeted drug delivery purposes.