Some polymers which are used in drugs are discussed below. 5. Chitosan is a polysaccharide polymer. Department of Applied Science, Indian Institute of Information Technology, Deoghat, Jhalwa, Allahabad, India, Creative Commons Attribution 4.0 International License. Biocompatible polymers provide better control over the toxicity of the samples; this leads to more reliable drug delivery and ensures patient’s safety. 2. Such dendrimers are very useful carriers for anti-tumour drugs [2] . The major benefits of smart polymer-based drug delivery systems includes reduced dosing frequency, ease of preparation, maintenance of desired therapeutic concentration with single dose, prolonged release of incorporated drug, reduced side effects and improved stability4, 5, 6. The Nobel Prize in Chemistry was awarded in 2000 for work on conductive polymers including polypyrrole. Diffusion based drug delivery systems (as shown in Figure 1) and solvent activated drug delivery systems are the other areas being explored for utilizing the polymers [1] . It is synthesized via free radical polymerization and is readily functionalized making it useful in a variety of applications. It is a biodegradable thermoplastic aliphatic polyester derived from renewable resources, such as co r n starch (in the United States and Canada), tapioca roots, chips or starch (mostly in Asia), or sugarcane (in the rest of the world). They patented this material in 1953. This is quite common. It has a variant, atelocollagen. From early beginnings using off-the-shelf mate … This work and the related PDF file are licensed under a Creative Commons Attribution 4.0 International License. There is a physiological labile bond between the drug and the polymer. Diffusion based drug delivery system [6] . Magneto/optical nanoparticles whether polymer coated or targeted are composed of iron oxides/polymers which are known to be safe, therefore have great future. One day a company of soft drinks sent them one sample of their product which became thick and sticky. Polymers used in colloidal drug carrier systems, consisting of small particles, show great advantage in drug delivery systems be-cause of optimized drug loading and releasing property. Surface modification of drug carriers e.g. Particle shape and size depend on variable parameters; among them, polymer type and concentration, stirring speed, pH and type of solvent. Development of smart polymer systems may lead to more accurate and programmable drug delivery. The polymer composition, the nature of the ionizable groups, the hydrophilicity of the polymer backbone and the cross linking density decide the behaviour of the smart polymers. They are being used in drug formulations and in drug delivery devices. Some smart polymer are formed by the cross linking of the pH sensitive smart polymeric chains. Examples of pharmaceutical polymers and the principles of controlled drug delivery are outlined and applications of polymers for controlled drug delivery are described. Alginate gel beads are co-precipitated with a biologically active agent to form a sustained release gels. They are used for production of hydrogels and other materials. Polymers used in colloidal drug carrier systems, consisting of small particles, show great advantage in drug delivery systems because of optimized drug loading and releasing property. Gamma PGA is formed by bacterial fermentation. ・ Polyesters: They have esters bond in the main chain [19] . Topical polymers are mostly prepared by organic polymers such as carbomers [21] . Polymers play a versatile role in such conventional formulations; they serve as binding agents in capsules, film coating agents in tablets and viscosity enhancers in emulsions and suspensions. ・ Polyorthoesters: A number of studies have been done on the use of polyorthoesters as encapsulating material for various drugs. Gelatin is a thermoreversible polymer [19] . Atelocollagen preparation involves removal of the telopeptide from collagen. 18. Polymers in Novel Drug Delivery Systems. They are stable colloidal system with solid hydrophobic core. It is composed of an FA tablet containing PVA, magnesium stearate and microcrystalline cellulose. POLYMER USED IN CONTROL DRUG DELIVERY SYSTEM Polymers are becoming increasingly important in the field of drug delivery. Polymer selection greatly influences the performance of the drug delivery system. It is a type of organic polymer formed by polymerization of pyrrole. The polymers mostly used in the non-biodegradable implants include polyvinyl alcohol (PVA), silicone and ethylene vinyl acetate (EVA). The use of these two biodegradable polymers have great advantages for sustained injectable drug delivery systems. Drugs are bound with magnetic nanoparticles e.g. PEGylation was considered to minister many diseases like hepatits B and C, neutropaenia connected with cancer chemotherapy (PEG-GCSF) 28 and various types of cancers [PEG] glutaminase merged with a glutamine anti-metabolite 6-diazo-5-oxo-norleucine (DON]. The total dose of a drug is lower than other drug delivery systems. Sialylated dendrimers are inhibitors of the haemagglutinin of human erythrocytes by influenza viruses [2] . Polymers are playing important role in pharmaceuticals. 12. Polyglutamic acid (PGA) is a polymer of the amino acid glutamic acid (GA). They can be easily removed from the body because they can be degraded into their diacid counter parts in vivo [19] . PVA is used as controlled elution membrane in the release area because they are permeable to various lipophilic drugs. Implants approved by the FDA for eye: Retisert, Vitrasert, and Ozurdex [2] . Copyright © 2020 by authors and Scientific Research Publishing Inc. Chemical engineers, pharmacologists and scientists are using polymers for developing controlled drug release systems and sustained release formulations [3] . The distribution of the size should be as narrow as possible since the rate at which the drug will be released as well as syringability depends on the size of the sphere directly. Among these, PLGA, the copolymer of PLA and PGA are mostly used polymers in drug delivery [18] [23] . Difficult to scale the process up and production in high amounts is expensive as microspheres are batch operations inherently [9] . Peer review under responsibility of Institute of Materia Medica, Chinese Academy of Medical Sciences and Chinese Pharmaceutical Association. Synthetic biodegradable polymers are also present that include PLA, PLGA, PGA, poly(phosphazenes), poly(caprolactone), poly(anhydride), poly(phosphoesters), poly(cyanoacry- lates), poly(acrylic acid), poly(amides), poly(ortho esters), polyethylene glycol, and polyvinyl alcohol and poly (isobutylcynoacrylate), poly(ethylene oxide), and poly(paradioxane). Download the powerpoint by liking us on Facebook Hydrogels have an ability to rapidly swell with water which may lead to faster release of the loaded drug than desired followed by the degradation of the polymer [10] . In past two decades poly lactic-co-glycolic acid (PLGA) has been among the most attractive polymeric candidates used to fabricate devices for drug delivery and tissue engineering applications. They offer protection against chemical degradation. Gold nanoparticles are easy to prepare, good capability of co existence, and their capacity to attach with other biomolecules without changing their properties. Figure 4. The pharmaceutical applications of polymers range from their use as binders in tablets to viscosity and flow controlling agents in liquids, suspensions and emulsions. Dendrimers also act as carriers (vectors), in gene therapy [26] . Polymers which are used in its preparation include the natural gums tragacanth, pectin, agar, alginic acid and carrageenan; semi synthetic materials such as hydroxyethyl cellulose, methylcellulose, carboxymethyl cellulose and hydroxypropylmethyl cellulose; and the synthetic polymer, carbopol [21] . Due to the presence of amide groups and hydrogen bonds, they have good mechanical properties and show high polar behaviour [19] . Polymer drug conjugates such as Zoladex, Lupron Depot, On Caspar PEG intron are used in treatment of prostate cancer and lymphoblastic leukemia. We focus on all drugs in pellet form achieving a highly desired physicochemical and pharmacokinetic profile, which ensures finely controlled dosing and optimal drug efficacy. Polymer nanoparticles for drug carrier systems can be prepared in a diversity of methods. Dendrimers are hyperbranched, monodisperse (uniform size particles in a dispersed phase), 3-D molecules of size 1 - 100 nm macromolecules. Advantages of controlled release dosage forms: The major advantage of a controlled release drug delivery system is that it allows the release of drugs at controlled rates over long periods; it can be from days to months. Through this paper we emphasize on the role of polymers in existing and novel drug delivery systems both as formulations and in devices, their advantages and limitations. Non toxic, biodegradable and biocompatible polymers are available. 2. 6. Recent advancements in polymer based encapsulations and controlled drug release systems help in regulating drug administration by preventing under or overdosing [2] . They are amphiphilic. The versatility of polymer sources and their combinatorial synthesis make it possible to tune polymer sensitivity to a given stimulus within a narrow range. Poly (methacrylic acid) jointure with PEG, referred to as P (MAA-g-EG) has been used for oral protein delivery [3] . Collagen also has a poor mechanical strength and it cannot easily develop reproducible release rates [14] . Liposomes are vesicles composed of phospholipids and cholesterol. Polysaccharides are frequently used in the ocular mucoadhesive delivery system. The branching starts from α-1,3 linkages [1] . Like other dendrimers, PAMAMs have a sphere-like shape overall, and are typified by an internal molecular architecture consisting of tree-like branching, with each outward “layer”, or generation, containing exponentially more branching points. Linear structure is formed by covalent bonding between monomer units such as amides, ester, orthoesters, and glycosidic bonds [19] . Polymers can be used as film coatings PANAM (polyamidoamine) dendrimers are also being used as carrier of genetic material. These are hydrophilic polymers and have linear structures used in topical drug delivery. They are used as binders in tablet, increases solubility of poorly soluble drugs, used as film coatings on drugs to disguise their taste and enhances their stability etc. The permeability and thickness of the polymer, the solubility and the release area of the drug determines the release kinetics of the drug form the diffusion controlled system. In targeted drug delivery systems the site of action should be clearly known. Polymeric porous particles are currently used for various applications in biotechnology, tissue engineering and pharmaceutical science, e.g., floating drug delivery systems and inhaled formulations. PAMAM dendrimers, sometimes referred to by the trade name Starburst, have been extensively studied since their synthesis in 1985, and represent the most well-characterized dendrimer family as well as the first to be commercialized. The cross linking density affects the permeability of the solute inversely, the higher the cross linking density, the lower the permeability [27] . The following review presents an overview of the different biodegradable polymers that are currently being used and their properties, as well as new developments in their applications. Download : Download full-size image; Figure 1. Internally Regulated Systems. 13. It has been studied in phase III trials. These systems introduced the following advantages compared with other methods of delivery: (1) the possibility of maintaining plasma drug levels in the optimal therapeutic range, (2) the eventuality to remove or decrease damaging side effects from systemic drug delivery by the local administration from a controlled release system, (3) drug execution may be improved and facilitated in organs that are not … A number of polymers have been studied systematically from this point of view and there is every indication that the systems described have the potential to become clinically valuable and therefore marketable drug delivery systems. It is a temperature responsive polymer that was first synthesized in the 1950s.It can be synthesized from N-isopropylacrylamide which is commercially available. The total dose of a drug is lower than other drug delivery systems. Whether the drug delivery system relies on a biodegradable implant to deliver medicine subcutaneously or deep within the body, biodegradable polymers provide a safe framework for delivering medicine without harm. Biodegradable polymers break due to cleavage of covalent bonds between them and bio erodible polymers bring about erosion of the polymer due to dissolution of linking chains without bringing about any change in chemical structure of the molecule [2] . Implants for controlled release of drug delivery system in which the release area because they can be into... Surrounds the core of solid drugs first synthesized in the ocular mucoadhesive delivery system polymers are ruptured biologically. Be classified as non-biodegradable and biodegradable feature, PLA, PGA and copolymer! Undergo a negative temperature-dependent phase transition can not easily develop reproducible release rates [ 14 ] lipid are! 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