Carboxymethyl chitosan CMCS

Figure 10.11 Schematic diagram of (a) formation of small interfering RNA (siRNA) loaded polyethylene glycol (PEG)- carboxymethyl chitosan (CMCS)/CaP hybrid anionic nanoparticles (NPPEG-CMCS/CaP/siRNA). (b) NPPEG-CMCS/CaP/siRNA for systemic delivery of human telomerase reverse transcriptase (hTERT) siRNA in anticancer therapy.

Many PECs are prepared using chitosan as the polycationic component, therefore they will be discussed separately. Chitosan, the product of N-deacetylation of chitin, is one of the most commonly used cationic polymers of pharmaceutical interest due to its biocompatibility, nontoxicity, and mucoadhesivity. It is frequently used to form PECs, often in combination with alginate, carrageenan," hyaluronic acid, chondroitin sulfate (CS)," carboxymethyl cellulose (CMC), or poly(galacturonic acid), since these are natural anionic polysaccharides with favorable pharmaceutical properties. 

As a cationic biopolymer, chitosan may react with any other anionically charged polyelectrolyte, giving rise to the formation of PEC [101, 104]. There are reports of PEC between chitosan and carboxymethyl cellulose (CMC) [105-108], alginate [109-112], poly(acrylic acid) [107, 113, 114], pectin [73, 115-117], carrageenans [118-121], heparin [122] and others [123-131]. 

In order to develop an efficient drug delivery carrier it is important for it to possess the following qualities. It should be immediately and completely removed after delivering drugs, it should not be accumulative or toxic in nature. Recent studies have proved the applicability of some chitin derivatives such as carboxymethyl chitin (CMC), chitosan hydrogel, and hydroxy-ethyl chitin have been shown to possess such characteristics (Ishihara et al., 2006 Dev et al., 2010). 

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