Methylated N-(4-N,N-dimethylaminobenzyl) chitosan coated liposomes for oral protein drug delivery.

In the present study, methylated N-(4-N,N-dimethylaminobenzyl) chitosan (TM(56)Bz(42)CS) was synthesised and investigated for oral protein drug delivery by combining it with liposomes entrapped with fluorescein isothiocyanate-conjugated bovine serum albumin (FITC-BSA), a model protein. Liposomes (LPs) composed of 10:2 molar ratios of egg yolk phosphatidylcholine (EPC) and sodium oleate (NaO) were prepared by a thin film hydration method and coated with TM(56)Bz(42)CS. BSA-loaded, TM(56)Bz(42)CS-coated liposomes (TM(56)Bz(42)CS-coated FITC-BSA-LP) were evaluated for their protein transport efficiencies and cytotoxicities in Caco-2 cells. Moreover, the in vitro stabilities of the TM(56)Bz(42)CS-coated LP-BSA were determined by examining the degradation of the protein in simulated intestinal fluid containing 1% w/v pancreatin porcine pancreas. The mean particle size and zeta-potential of the TM(56)Bz(42)CS-coated LP-BSA were 128 ± 15 nm and 5.38 ± 1.66 mV, respectively. Additionally, the initial FITC-BSA to lipid ratio (2.5% w/w) showed the highest entrapment efficiency percentage (50.13%) and FITC-BSA content (8.08 mg/g of lipid) overall. The results of the FITC-BSA transport showed that the TM(56)Bz(42)CS-coated FITC-BSA-LP enhanced protein permeability across the Caco-2 cell monolayers with low cytotoxicity. In addition, these liposomes protected against protein degradation in pancreatin. Our studies demonstrated that TM(56)Bz(42)CS-coated liposomes have the potential to be used in oral protein drug delivery methods.

Methylated N-(4-N,N-dimethylaminocinnamyl) chitosan enhances paracellular permeability across Caco-2 cells.

The effect of methylated N-(4-N,N-dimethylaminocinnamyl) chitosan (TM-CM-CS) was investigated on paracellular permeability and its toxicity towards Caco-2 cells. Fluorescein isothiocyanate dextran 4,400 (FD-4) was used as the model compound for paracellular transport. The factors, i.e. the degree of quaternization (DQ) and the extent of N-substitution (ES) of the derivatives, were studied for the effect on transepithelial electrical resistance (TEER) and permeability. The results revealed that at pH 7.4, TM-CM-CS appeared to increase cell permeability in a dose-dependent manner, and the effect was relatively reversible at lower doses of 0.05-0.5 mM. The difference of the DQ and the ES of TM-CM-CS slightly affected the decrease of TEER values and the FD-4 permeability. The cytotoxicity of TM-CM-CS was concentration-dependent and did not cause an acute cytotoxic effect as analyzed by the MTT assay. These studies demonstrated that this novel modified chitosan has the potential to be used as an intestinal absorption enhancer of therapeutic macromolecules.

In vitro permeability enhancement in intestinal epithelial cells (Caco-2) monolayer of water soluble quaternary ammonium chitosan derivatives.

The aim of this study was to investigate the effects of a type of hydrophobic moiety, extent of N-substitution (ES), and degree of quaternization (DQ) of chitosan (CS) on the transepithelial electrical resistance and permeability of Caco-2 cells monolayer, using fluorescein isothiocyanate dextran 4,400 (FD-4) as the model compound for paracellular tight junction transport. CS was substituted with hydrophobic moiety, an aliphatic aldehyde (n-octyl) or aromatic aldehyde (benzyl), for the improved hydrophobic interaction with cell membrane, and they were quaternized with Quat-188 to render CS soluble. The factors affecting the epithelial permeability have been evaluated in the intestinal cell monolayers, Caco-2 cells. Cytotoxicity was evaluated by using the trypan blue and MTT viability assay. The results revealed that at pH 7.4 CSQ appeared to increase cell permeability in dose-dependent manner, and this effect was relatively reversible at the lower doses of 0.05-1.25 mM. The higher DQ and ES caused the higher permeability of FD-4. Cytotoxicity of CSQ was concentration, %DQ, and %ES dependent. Substitution with hydrophobic moiety caused decreasing in permeability of FD-4 and cytotoxicity by benzyl group had more effect than octyl group. These studies demonstrated that these novel modified chitosan derivatives had potential for using as absorption enhancers.

Cellular transport of anti-inflammatory pro-drugs originated from a herbal formulation of Zingiber cassumunar and Nigella sativa.

BACKGROUND: The rhizome of Zingiber cassumunar and the seed of Nigella sativa are two ingredients in Thai traditional medicine to relieve dysmenorrhea and adjust the menstrual cycle. Mixture of these two herbs produces three esters, namely (E)-4-(3,4-dimethoxyphenyl)but-3-en-1-yl linoleate (1), (E)-4-(3,4-dimethoxyphenyl)but-3-en-1-yl oleate (2) and (E)-4-(3,4-dimethoxyphenyl)but-3-en-1-yl palmitate (3). The aim of this study is to examine in vitro absorption of these esters and evaluate their transport across the membrane. METHODS: In vitro transport of these three esters was observed in Caco-2 cell monolayers. The ester compounds 1, 2 and 3 at a concentration of 10 microM were hydrolyzed by porcine liver esterase. RESULTS: All esters transported across the Caco-2 cell without enzymatic hydrolysis. The apparent permeability coefficients P(app) of compound 1 at 53 microM and 106 microM were 13.94 (0.60) x 10(-6) and 14.33 (0.17) x 10(-6) cm/s respectively, while those of compound 2 were 9.45 (0.29) x 10(-6) and 10.08 (0.32) x 10(-6) cm/s, respectively. Papp values of compound 3 were 7.48 (0.31) x 10(-6) cm/s at 53 microM and 8.60 (0.55) x 10(-6) cm/s at 106 microM. P(app) values of the parent compound (compound D), i.e. (E)-4-(3,4-dimethoxyphenyl)but-3-en-1-ol were 8.53 (0.83) x 10(-6) cm/s at 53 microM and 16.38 (0.61) x 10(-6) cm/s at 106 microM. The ester hydrolysis of compounds 1, 2 and 3 by porcine liver esterase was monitored by HPLC and the hydrolysis reactions were completed within 10 minutes. CONCLUSION: Using the Caco-2 cell monolayer model, the present study finds that compounds (E)-4-(3,4-dimethoxyphenyl)but-3-en-1-yl linoleate (1), (E)-4-(3,4-dimethoxyphenyl)but-3-en-1-yl oleate (2) and (E)-4-(3,4-dimethoxyphenyl)but-3-en-1-yl palmitate (3) originated from Prasaplai preparation (a Thai herbal formula) may be transported through a facilitated mechanism and serve as pro-drugs to increase the compound D level in the blood.

Methylated N-(4-N,N-dimethylaminobenzyl) chitosan, a novel chitosan derivative, enhances paracellular permeability across intestinal epithelial cells (Caco-2).

The aim of this study was to investigate the effect of methylated N-(4-N,N-dimethylaminobenzyl) chitosan, TM-Bz-CS, on the paracellular permeability of Caco-2 cell monolayers and its toxicity towards the cell lines. The factors affecting epithelial permeability, e.g., degree of quaternization (DQ) and extent of dimethylaminobenzyl substitution (ES), were evaluated in intestinal cell monolayers of Caco-2 cells using the transepithelial electrical resistance and permeability of Caco-2 cell monolayers, with fluorescein isothiocyanate dextran 4,400 (FD-4) as a model compound for paracellular tight-junction transport. Cytotoxicity was evaluated with the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide viability assay. The results revealed that, at pH 7.4, TM-Bz-CS appeared to increase cell permeability in a concentration-dependent manner, and this effect was relatively reversible at lower doses of 0.05-0.5 mM. Higher DQ and the ES caused the permeability of FD-4 to be higher. The cytotoxicity of TM-Bz-CS depended on concentration, %DQ, and %ES. These studies demonstrated that this novel modified chitosan has potential as an absorption enhancer.