Development and In Vitro Characterization of Galactosylated Low Molecular Weight Chitosan Nanoparticles Bearing Doxorubicin

The aim of the present research was to evaluate the potential of galactosylated low molecular weight chitosan (Gal-LMWC) nanoparticles bearing positively charged anticancer, doxorubicin (DOX) for hepatocyte targeting. The chitosan from crab shell was depolymerized, and the lactobionic acid was coupled with LMWC using carbodiimide chemistry. The depolymerized and galactosylated polymers were characterized. Two types of Gal-LMWC(s) with variable degree of substitution were employed to prepare the nanoparticles using ionotropic gelation with pentasodium tripolyphosphate anions. Factors affecting nanoparticles formation were discussed. The nanoparticles were characterized by transmission electron microscopy and photon correlation spectroscopy and found to be spherical in the size range 106–320 nm. Relatively higher percent DOX entrapment was obtained for Gal-LMWC(s) nanoparticles than for LMWC nanoparticles. A further increase in drug entrapment was found with nanoparticles prepared by Gal-LMWC with higher degree of substitution. A hypothesis which correlates the ionic concentration of DOX in nanoparticles preparation medium and percent DOX entrapment in cationic polymer has been proposed to explain the enhanced DOX entrapment. In-vitro drug release study demonstrated an initial burst release followed by a sustained release. The targeting potential of the prepared nanoparticles was assessed by in vitro cytotoxicity study using the human hepatocellular carcinoma cell line (HepG2) expressing the ASGP receptors on their surfaces. The enthusiastic results showed the feasibility of Gal-LMWC(s) to entrap the cationic DOX and targeting potential of developed Gal-LMWC(s) nanoparticles to HepG2 cell line

Effects of proteins on the permeability of monolayers of cultured bovine arterial endothelium.

1. Monolayers of arterial endothelium on porous membranes were exposed to a pressure of 15 cmH2O at 37 degrees C, or of 30 cmH2O at 0 degree C. At constant pressure, the rate of liquid flow per unit area (Jv/A) through each monolayer decreased with time, in the way previously described for cultured endothelium. This phenomenon has been called sealing. After Jv/A stabilized, the pressure was reduced and the hydraulic permeability (Lp) of the endothelium was calculated from the relationship between Jv/A and pressure. Endothelium was seen to be damaged after some experiments at 37 degrees C, but appeared undamaged after experiments at 0 degree C. 2. Bovine serum albumin (BSA) did not influence the Lp of cultured endothelium. At 37 degrees C, the mean (+/- S.E.M.) endothelial Lp was 47.2 +/- 7.3 x 10(-7) cm s-1 cmH2O-1 (n = 10) in the presence of BSA (5 g (100 ml)-1). This is not significantly different from the mean (+/- S.E.M.) Lp of 53.4 +/- 9.0 x 10(-7) cm s-1 cmH2O-1 (n = 9) in the absence of added protein (P greater than 0.10). At 0 degree C also, there was no significant difference between mean Lps in the presence of BSA (0.1 g (100 ml)-1) and in the absence of added protein. 3. Solutions of BSA (5 g (100 ml)-1 or of the neutral polymer Ficoll 70 (4 g (100 ml)-1) did not exert any effective osmotic pressure across endothelium at 37 or 0 degrees C, respectively. 4. BSA (0.1 g (100 ml)-1) did not enable solutions of Ficoll 70 (4 g (100 ml)-1) to exert an effective osmotic pressure across endothelium at 0 degree C. 5. The mean Lp of endothelium at 0 degree C was significantly lower in the presence of cationized ferritin (CF; 0.1 g (100 ml)-1) than in the absence of added protein (P less than 0.001). Native ferritin (NF; 0.1 g (100 ml)-1) had no effect on Lp. 6. In the presence of CF (0.1 g (100 ml)-1), solutions of Ficoll 70 (4 g (100 ml)-1) exerted a mean effective osmotic pressure of 27.7 cmH2O (n = 5) across endothelium at 0 degree C. The mean effective osmotic pressure exerted across endothelium by solutions of Ficoll 70 (4 g (100 ml)-1) plus NF (0.1 g (100 ml)-1) was 1.2 cmH2O (n = 4)