Polymer as Novel Drug Carrier

Aakanchha Jain, Sourabh Jain, Vikas Jain, and Dharmveer Kohli  

Chitosan is a second abundant heteropolysaccharide composed of /3-[l-4]-2-deoxy-2-amino and -2-acetamino D-glucopyranose units [31]. Chitosan is the partial deacetylated (involving alkaline hydrolysis] product of chitin. Chltln is the main component of outer skeleton of small insects, cuticles, and the shells of shrimp, crab, lobster, etc. Chitosan has been expansively investigated in the pharmaceutical industries for the development of various sustained and controlled release drug delivery systems due to its versatile biological activity [as food and non-food items] and excellent biocompatibility. Hirano [22] conducted an experiment with both healthy and infected skin and found the LD50 in case of orally administered mouse to be [ 16 g/kg]. Wu et al. [76] worked on 

Handbook of Sustainable Polymers Processing and Applications Edited byVijay KumarThakur and Manju KumariThakur Copyright 2016 Pan Stanford Pubiishing Pte. Ltd. iSBN 978-981-4613-53-8 (Hardcover), 978-981-4613-54-5 (eBook) WWW. pa n sta nford. com 

Chitosan as a polymer is so well known that it has found place in many official books, encyclopedias, monographs, American Standard Testing Materials, and in Pharmacopoeias of various countries. 

The three main active functional groups of chitosan include an amino/acetamido group and both primary and secondary hydroxyl groups at the C2, C3, and C6 positions, respectively. Easy generation of both inter- and intra-molecular hydrogen bonds, which causes variation in their structures and physicochemical properties is mainly associated with the amount of amino contents 

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Yokoyama, M. Miyauchi, M. Yamada, N. Okano, T. Sakurai, Y. Kataoka, K. Inoue, S. Polymer micelles as novel drug carrier—adriamycin-conjugated poly(ethylene glycol) poly(aspartic acid) block copolymer. J. Control. Release 1990, 11 (1-3), 269-278. 

Zhou et al. described the synthesis of pH-sensitive biodegradable PUs. They used a novel pH-sensitive macrodiol containing acid-cleavable hydrazone linkers, poly(E-caprolactone)-hydrazone-poly(ethylene glycol)-hydiazone- ly(E-caprolactone) diol (PCL-Hyd-PEG-Hyd-PCL). The macrodiol was used with L-lysine ethyl ester diisocyanate (LDI) and L-lysine-derived tripeptide as chain extender [47]. These PUs could self-assemble into micelles in aqneons solutions. Later, the same research group synthesized pH-sensitive polymers nsing 1,4-bntanediol as chain extenders and suggested its use as antitumor drug carriers [41]. 

Piskin E, Haitian X, Denkbas EB, Kucukyavuz Z. Novel PDLLA/PEG copolymer micelles as drug carriers. J Biomater Sci Polymer Edn 1995 7 359-373. 

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