Animals were treated with equivalent doses of DOX (3 mg/kg) and NChitosan-DMNPs suspended in PBS by intravenous injection every 2 days for 12 days. At predetermined time periods, the length

of the minor axis (2a) and major axis (2b) of each tumor was measured using a caliper. Each tumor volume was then calculated using the formula for ellipsoid QNZ ic50 [(4/3)π × a2b]. MR imaging In vivo MR imaging experiments were performed using a 3.0 T clinical MRI instrument with a micro-47 surface coil (Intera; Philips Medical Systems, Best, The Netherlands). The T2 weights of nude mice injected with nanoparticles were measured by Carr-Purcell-Meiboom-Gill sequence at room temperature with the following parameters: TR = 10 s, echoes = 32 with 12 ms even echo space, number of acquisitions = 1, point resolution = 156 × 156 μm, and section thickness = 0.6 mm. For T2-weighted MR imaging in the nude mouse model, the following parameters were adopted: resolution = 234 × 234 μm2, section thickness = 2.0 mm, TE = 60 ms, TR = 4,000 ms, and number of acquisitions = 1. Results and discussion Characterization selleck chemicals of N-naphthyl-O-dimethymaleoyl chitosan

N-naphthyl-O-dimethymaleoyl chitosan was synthesized by modifying chitosan with naphthyl groups at amino groups to complement their solubility and introduce amphiphilic properties [79]. Chitosan was reacted with naphthaldehyde to obtain an imine (Schiff base), which is easily converted into an www.selleckchem.com/products/Dasatinib.html N-naphthyl derivate by

reduction with sodium borohydride or sodium cyanoborohydride (Figure 2a). Afterward, N-NapCS was introduced into the hydroxyl groups of chitosan by maleoylation with dimethylmaleic anhydride in DMF/DMSO to obtain N-nap-O-MalCS (Figure 2b) [67, 68]. This synthetic compound was characterized by a 1H-NMR spectrum, and satisfactory analysis data were obtained (Figure 3). N-nap-O-MalCS was used to form nanopolymeric micelles by dialysis in various MycoClean Mycoplasma Removal Kit pH solutions. They were less than 200 nm at pH 7.2 to 8.0 but rapidly increased in size as the acidity of solution increased (Figure 4). Their sizes could not be measured at pH 5.5 and 6.0 (Figure 4a) due to aggregation. This was a result of the weakened solubility of N-nap-O-MalCS in the aqueous phase caused by acid hydrolysis of its maleoyl groups [80, 81]. This phenomenon accelerated at 37°C compared to 25°C (Figure 4b). N-Nap-O-MalCS has a potential as a drug carrier because it can self-assemble with pH-sensitive behavior [67, 68, 79, 82]. Figure 3 1 H-NMR spectrum of N -nap- O -MalCS. (a) -CH- in aromatic ring. (b) -CH2-. (c) -CH. (d) -CH3. Figure 4 Effect of N -nap- O -MalCS polymeric micelles in various pH conditions and temperatures. (a) Stability. (b) Particle size.