What are Polymeric Nanoparticles ? As name only suggest polymeric nanoparticles are nanoparticles which are prepared from polymers. The drug is dissolved, entrapped, encapsulated or attached to a nanoparticles and depending upon the method of preparation, nanoparticles, nanospheres or nanocapsules can be obtained. Nanocapsules are vesicular systems in which the drug is confined to a cavity surrounded by a polymer membrane, while nanospheres are matrix systems in which the drug is physically and uniformly dispersed. In recent years, biodegradable polymeric nanoparticles have attracted considerable attention as potential drug delivery devices in view of their applications in drug targeting to particular organs/tissues, as carriers of DNA in gene therapy, and in their ability to deliver proteins, peptides and genes through a per oral route of administration. . In spite of development of various synthetic and semi synthetic polymers, natural polymers still enjoy their popularity in drug delivery, some of them are listed bellow.        Gums (Ex. Acacia, Guar, etc.)        Chitosan        Gelatin        Sodium alginate        Albumin A range of materials have been employed to delivery of bioactive agents. Pharmaceutical Scientist borrowed polymers intended for other, non biological uses. A polymer used in controlled drug delivery formulations, must be chemically inert, non-toxic and free of leachable impurities. It must also have an appropriate physical structure, with minimal undesired aging, and be readily processable. Some of the polymeric materials are listed bellow.      Cellulosics.        Poly(2-hydroxy ethyl methacrylate).      Poly(N-vinyl pyrrolidone).      Poly(methyl methacrylate).      Poly(vinyl alcohol).      Poly(acrylic acid).      Polyacrylamide.      Poly(ethylene-co-vinyl acetate).      Poly(ethylene glycol).      Poly(methacrylic acid). However, in recent years additional polymers are designed primarily for medical applications and have entered the arena of controlled release of bioactive agents. Many of these materials are designed to degrade within the body, most popular ones are;        Polylactides (PLA).        Polyglycolides (PGA).        Poly(lactide-co-glycolides) (PLGA).        Polyanhydrides.        Polyorthoesters.        Polycyanoacrylates        Polycaprolactone Originally, polylactides and polyglycolides were used as absorbable suture material. The main advantage of these degradable polymers is that they are broken down into biologically acceptable molecules that are metabolized and removed from the body via normal metabolic pathways. However, biodegradable materials do produce degradation by-products that must be tolerated with little or no adverse reactions within the biological environment. Abraxane is the first polymeric nanoparticle based product from American Pharmaceutical Partners, Inc., and American Bioscience, Inc. (ABI). It was approved in year 2005 and is consisting of albumin-bound paclitaxel nanoparticles. This product is free of toxic solvents like cremophor-EL, which is used until now to solubalize paclitaxel in order to administer it intravenously to the patient. cremophor-EL is known to cause life-threatening allergic reactions.  Success of Abraxane show that nanotechnology can bring many exciting products which can overcome many hurdle of formulation scientist.

Companies

Am. Pharm Partners BioAlliance Pharma Copernicus Therapeutics Insert Therapeutics SoluBest

Polymer Suppliers

Boehringer Ingelheim Purac Brimingham Polymers Sigma-Aldrich

How Polymeric Nanoparticles are Engineered? Polymeric nanoparticles are engineered by various methods and some of them are listed bellow; Emulsification followed by solvent evaporation/cross-linking Emulsion polymerization Spray drying Supercritical fluid technology Electrospray method Related Publications DNA nano-carriers from biodegradable cationic branched polyesters are formed by a modified solvent displacement method NEW Journal of Controlled Release, 2006, 371-381, 111,371-381   G-CSF loaded biodegradable PLGA nanoparticles prepared by a single oil-in- water emulsion method International Journal of Pharmaceutics, 2006, 311, 223-228. Biodegradable polymeric nanoparticles as drug delivery devices Journal of Controlled Release, 2001, 70, 1-20. A novel controlled release formulation for the anticancer drug paclitaxel (Taxol (R)): PLGA nanoparticles containing vitamin E TPGS Journal of Controlled Release, 2003, 86, 33-48. Preparation and evaluation of thiol-modified gelatin nanoparticles for intracellular DNA delivery in response to glutathione Bioconjugate Chemistry, 2005, 16, 1423-1432. Patent Watch Vitamin B12 --biodegradable micro particulate conjugate carrier systems for peroral delivery of drugs, therapeutic peptides/proteins and vaccines Chalasani ,   et al.  USPT 6,482,413, November 19, 2002. Method of forming nanoparticles and microparticles of controllable size using supercritical fluids with enhanced mass transfer    Gupta ,   et al. USPT 6,620,351, September 16, 2003   Drug targeting to the nervous system by nanoparticles Kreuter ,   et al.  USPT 6,117,454  September 12, 2000

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