Preparation and Characterization of Camptothecin Grafted Chitosan Oligosaccharide Nanomicelles

Abstract

Water soluble chitosan oligosaccharide (CHO) was hydrophobically modified with camptothecin (CPT) in different molar ratios of CPT, and characterized by FT‐IR and 1H‐NMR spectroscopy. Nanomicelles prepared by these copolymers were analyzed for size, zeta, and length of time they remain stable. The critical micelle concentration (CMC) and dissociation of micelles at physiological pH and acidic pH were also investigated. FT‐IR and 1H‐NMR spectroscopy approved chemical modification of CHO. Fluorometry study showed that the CMC of grafted copolymer decreased from 27.2×10 to 6.1×10 g/L with an increasing feeding ratio from 2.5 to 7.5. Particle size of CPT‐CHO‐2.5 and CPT‐CHO‐7.5 was 539 ± 152.15 and197.8±66 nm, respectively. The dissociation study showed that the micelles are stable, and the disassembly was not observed in water at 37ºC neither at pH of 7.4 nor at pH of 5.5. These phenomena make CPT‐CHO micelles as stable polymeric micelles for drug delivery.