A Simple Colorimetric Method to Quantify Total Fecal Oil Using Oil-soluble Dyes in Laboratory Animals and Its Correlation with Liquid Chromatography-Mass Spectrometry Analysis.

We developed a colorimetric method for measuring the amount of oil in mouse stool after co-administering an oil-soluble dye. When the amount of oil in the feces calculated from the amounts of Sudan III and Oil Red O was plotted against the amount of oil detected by liquid chromatography-mass spectrometry, the graph was linear, showing a one-to-one correlation between two analyses. This method may be utilized to determine the efficacy of lipase inhibitors, or to assess fat malabsorption in vivo.

Chitosan dosage regimen to trap fecal oil excretion after peroral lipase inhibitor administration in mice.

This study was designed to investigate the oil entrapment and systemic oil absorption-reducing activities of chitosan. High-molecular-weight chitosan formed gel aggregates with oil and bile salts in vitro. The oil/chitosan ratio and the molecular weight of chitosan were optimized for the in vivo study, and a molecular weight >100,000 was effective in reducing the oil contamination of mouse fur. The oil/chitosan weight ratio required for effective oil entrapment was less than 13 and 5 in the in vitro and in vivo experiments, respectively. Chitosan administration was most effective during meals, and high-molecular-weight chitosan could trap and facilitate the reduction of systemic absorption of oil droplets separated by orlistat. The activity of the lipase inhibitor was not altered by chitosan as evidenced by thin layer chromatography, and orlistat was not absorbed systemically by the co-administration of chitosan.

Absorption mechanism of DHP107, an oral paclitaxel formulation that forms a hydrated lipidic sponge phase.

Paclitaxel is a most widely used anticancer drug with low oral bioavailability, thus it is currently administered via intravenous infusion. DHP107 is a lipid-based paclitaxel formulation that can be administered as an oral solution. In this study, we investigated the mechanism of paclitaxel absorption after oral administration of DHP107 in mice and rats by changing the dosing interval, and evaluated the influence of bile excretion. DHP107 was orally administered to mice at various dosing intervals (2, 4, 8, 12, 24 h) to examine how residual DHP107 affected paclitaxel absorption during subsequent administration. Studies with small-angle X-ray diffraction (SAXS) and cryo-transmission electron microscopy (cryo-TEM) showed that DHP107 formed a lipidic sponge phase after hydration. The AUC values after the second dose were smaller than those after the first dose, which was correlated to the induction of expression of P-gp and CYP in the livers and small intestines from 2 h to 7 d after the first dose. The smaller AUC value observed after the second dose was also attributed to the intestinal adhesion of residual formulation. The adhered DHP107 may have been removed by ingested food, thus resulting in a higher AUC. In ex vivo and in vivo mucoadhesion studies, the formulation adhered to the villi for up to 24 h, and the amount of DHP107 that adhered was approximately half that of monoolein. The paclitaxel absorption after administration of DHP107 was not affected by bile in the cholecystectomy mice. The dosing interval and food intake affect the oral absorption of paclitaxel from DHP107, which forms a mucoadhesive sponge phase after hydration. Bile excretion does not affect the absorption of paclitaxel from DHP107 in vivo.

Photoinduced reversible phase transition of azobenzene-containing polydiacetylene crystals.

An azobenzene-containing supramolecular polydiacetylene (PDA) crystal undergoes a photoinduced reversible blue-to-red phase transition accompanied by crystal tearing.

Synthesis and T-type calcium channel-blocking effects of aryl(1,5-disubstituted-pyrazol-3-yl)methyl sulfonamides for neuropathic pain treatment.

A novel series of aryl(1,5-disubstituted pyrazol-3-yl)methyl sulfonamide derivatives was designed, synthesized, and evaluated for T-type calcium channel (α1G and α1H) inhibitory activity. We identified several compounds, 9a, 9b, 9g, and 9h that displayed good T-type channel inhibitory potency with low hERG channel and CYP450 inhibition. Among them, 9a and 9b exhibited neuropathic pain alleviation effects in mechanical and cold allodynia induced in the SNL rat model. Compounds 9a and 9b displayed better efficacy than mibefradil and gabapentin against cold allodynia. In particular, compound 9a seemed to be valuable as shown fast acting performance in mechanical neuropathic pain model.

The vest-collar as a rodent collar to prevent licking and scratching during experiments.

Various types of restraint collars have been used for research animals, and the Elizabethan collar (E-collar) is the most commonly used. However, animals can be choked by the E-collar or they tend to remove it; furthermore, repeated rubbing and scratching of the collar may chafe the neck. We developed a new restraint collar with a vest to overcome these limitations. The vest-collar (V-collar) can be worn similarly to a vest, in contrast to the E-collar, which is fixed around the neck. A cone-shaped collar is attached to the vest in the V-collar and is made of Eva foam to surround the chest softly, accompanied by a transparent polyvinyl chloride (PVC) film for visibility. To evaluate the performance of the V-collar, we conducted experiments with mice wearing the V-collar and the E-collar. Both groups showed normal weight gain and food intake. Glucose and stress hormone levels showed no significant differences, and no stress-associated leukocyte profiles were observed during the experiments. However, despite the short experimental duration, more than half of the mice in the E-collar group showed injury to the skin on the neck, with increased thickness of the epidermal and keratin layers. Moreover, inflammatory cell counts were higher in the E-collar group than in the V-collar group. In conclusion, the V-collar, in contrast to the E-collar, does not cause skin injuries in animals and is thus beneficial for animals and investigators. Investigators can effectively use the V-collar to enhance laboratory animal welfare.

Novel intraarterial therapy for liver cancer using ethylbromopyruvate dissolved in an iodized oil.

RATIONALE AND OBJECTIVES: In spite of various therapies developed, hepatocellular carcinoma still shows poor prognosis. In this study, we introduced ethylbromopyruvate (EBrP), a hydrophobic derivative of 3-bromopyruvate, as an agent for intraarterial therapy of hepatocellular carcinoma. MATERIALS AND METHODS: In in vitro study, we evaluated whether EBrP induced apoptotic cell death in Huh-BAT cells. Chemical degradation products of EBrP were identified by performing proton nuclear magnetic resonance spectroscopy and thin layer chromatography. VX2 carcinoma was implanted and grown in the liver of 25 rabbits for in vivo study. By transfemoral intraarterial approach, 0.4 mL of 10 mM and 40 mM EBrP dissolved in an iodized oil (Lipiodol) was infused into the proper hepatic artery in 8 and 10 rabbits, respectively. In the remaining seven rabbits, 0.4 mL of Lipiodol alone was intraarterially injected as a control. One week later, tumor necrosis rate was calculated with histopathologic examination and hepatotoxicity was evaluated with biochemical analysis. RESULTS: EBrP induced apoptosis in human HCC cells via mitochondrial apoptotic signaling cascades. EBrP dissociated into 3-bromopyruvate and ethanol in the aqueous environment. In VX2 liver tumor models, the group of intraarterial delivery of 40 mM EBrP/Lipiodol solution showed higher tumor necrosis rates (96.1% ± 3.8) than the other groups (38.9% ± 15.9 of a control, 90.5% ± 2.9 in 10 mM) (P < .05). There was transient elevation of AST and ALT enzyme levels without any mortality. CONCLUSIONS: Intraarterial infusion of EBrP/Lipiodol solution is a feasible intraarterial therapy for liver tumors with potent antitumor effects and transient hepatotoxicity.

The antitumor effect and hepatotoxicity of a hexokinase II inhibitor 3-bromopyruvate: in vivo investigation of intraarterial administration in a rabbit VX2 hepatoma model.

OBJECTIVE: The purpose of this study was to compare the antitumor effect and hepatotoxicity of an intraarterial delivery of low-dose and high-dose 3-bromopyruvate (3-BrPA) and those of a conventional Lipiodol-doxorubicin emulsion in a rabbit VX2 hepatoma model. MATERIALS AND METHODS: This experiment was approved by the animal care committee at our institution. VX2 carcinoma was implanted in the livers of 36 rabbits. Transcatheter intraarterial administration was performed using low dose 3-BrPA (25 mL in a 1 mM concentration, n = 10), high dose 3-BrPA (25 mL in a 5 mM concentration, n = 10) and Lipiodol-doxorubicin emulsion (1.6 mg doxorubicin/ 0.4 mL Lipiodol, n = 10), and six rabbits were treated with normal saline alone as a control group. One week later, the proportion of tumor necrosis was calculated based on histopathologic examination. The hepatotoxicity was evaluated by biochemical analysis. The differences between these groups were statistically assessed with using Mann-Whitney U tests and Kruskal-Wallis tests. RESULTS: The tumor necrosis rate was significantly higher in the high dose group (93% +/- 7.6 [mean +/- SD]) than that in the control group (48% +/- 21.7) (p = 0.0002), but the tumor necrosis rate was not significantly higher in the low dose group (62% +/- 20.0) (p = 0.2780). However, the tumor necrosis rate of the high dose group was significantly lower than that of the Lipiodol-doxorubicin treatment group (99% +/- 2.7) (p = 0.0015). The hepatotoxicity observed in the 3-BrPA groups was comparable to that of the Lipiodol-doxorubicin group. CONCLUSION: Even though intraarterial delivery of 3-BrPA shows a dose-related antitumor effect, single session treatment seems to have limited efficacy when compared with the conventional method.

Efficacy and tissue distribution of DHP107, an oral paclitaxel formulation.

Paclitaxel is indispensable in treating human cancers. Due to poor drug solubility and efflux systems in the gastrointestinal tract, peroral delivery of paclitaxel has been a significant challenge. We developed a mucoadhesive oral formulation (DHP107) that can directly and effectively deliver paclitaxel to intestinal endothelial cells without concomitant use of P-glycoprotein inhibitors. Here, we evaluated the tissue distribution of paclitaxel, the antitumor efficacy and the absorption mechanism of DHP107. DHP107, which contains 10 mg/mL of paclitaxel in a mixture of monoolein, tricarprylin, and Tween 80 was administered p.o. to female BALB/c mice at a 50 mg/kg dose. Diluted Taxol was administered via bolus tail-vein injection at 10 mg/kg as a control. Blood and tissue samples were harvested at various time points and analyzed by high-performance liquid chromatography. Tissue sections were observed using light microscopy after immunohistochemical and Oil Red O staining. By day 27, tumor volume after DHP107 and Taxol treatments was one-third of that in the untreated group. After p.o. administration, paclitaxel was widely distributed in various organs (T(max) = 2 h), especially liver, spleen, and lung. DHP107 was effectively absorbed through the intestinal lipid transport system. DHP107 changed spontaneously into <100-mum droplets and micelles in the intestine, which in turn adhered to mucoepithelial cells, were absorbed via lipid uptake mechanism, and formed lipid bodies in the epithelium. Paclitaxel in DHP107 was effectively absorbed through the gastrointestinal tract via lipid uptake mechanism and was distributed in various tissues. The detailed uptake mechanism is currently under investigation.

FDG-PET for evaluating the antitumor effect of intraarterial 3-bromopyruvate administration in a rabbit VX2 liver tumor model.

OBJECTIVE: We wanted to investigate the feasibility of using FDG-PET for evaluating the antitumor effect of intraarterial administration of a hexokinase II inhibitor, 3-bromopyruvate (3-BrPA), in a rabbit VX2 liver tumor model. MATERIALS AND METHODS: VX2 carcinoma was grown in the livers of ten rabbits. Two weeks later, liver CT was performed to confirm appropriate tumor growth for the experiment. After tumor volume-matched grouping of the rabbits, transcatheter intraarterial administration of 3-BrPA was performed (1 mM and 5 mM in five animals each, respectively). FDG-PET scan was performed the day before, immediately after and a week after 3-BrPA administration. FDG uptake was semiquantified by measuring the standardized uptake value (SUV). A week after treatment, the experimental animals were sacrificed and the necrosis rates of the tumors were calculated based on the histopathology. RESULTS: The SUV of the VX2 tumors before treatment (3.87+/-1.51 [mean+/-SD]) was significantly higher than that of nontumorous liver parenchyma (1.72+/-0.34) (p < 0.0001, Mann-Whitney U test). The SUV was significantly decreased immediately after 3-BrPA administration (2.05+/-1.21) (p = 0.002, Wilcoxon signed rank test). On the one-week follow up PET scan, the FDG uptake remained significantly lower (SUV 1.41+/-0.73) than that before treatment (p = 0.002), although three out of ten animals showed a slightly increasing tendency for the FDG uptake. The tumor necrosis rate ranged from 50.00% to 99.90% (85.48%+/-15.87). There was no significant correlation between the SUV or the SUV decrease rate and the tumor necrosis rate in that range. CONCLUSION: Even though FDG-PET cannot exactly reflect the tumor necrosis rate, FDG-PET is a useful modality for the early assessment of the antitumor effect of intraarterial administration of 3-BrPA in VX2 liver tumor.

Induction of immunity against hepatitis B virus surface antigen by intranasal DNA vaccination using a cationic emulsion as a mucosal gene carrier.

Delivery of DNA vaccines to airway mucosa would be an ideal method for mucosal immunization. However, there have been few reports of a suitable gene delivery system. In this study we used a cationic emulsion to immunize mice via the intranasal route with pCMV-S coding for Hepatitis B virus surface antigen (HBsAg). Complexing pCMV-S with a cationic emulsion dramatically enhanced HBsAg expression in both nasal tissue and lung, and was associated with increases in the levels of HBs-specific Abs in serum and mucosal fluids, of cytotoxic T lymphocytes (CTL) in the spleen and cervical and iliac lymph nodes, and of delayed-type hypersensitivity (DTH) against HBsAg. In contrast, very weak humoral and cellular immunities were observed following immunization with naked DNA. In support of these observations, a higher proliferative response of spleenocytes was detected in the group immunized with the emulsion/pCMV-S complex than in the group immunized with naked pCMV-S. These findings may facilitate development of an emulsion-mediated gene vaccination technique for use against intracellular pathogens that invade mucosal surfaces.

Intraarterial gene delivery in rabbit hepatic tumors: transfection with nonviral vector by using iodized oil emulsion.

PURPOSE: To evaluate the feasibility of an iodized oil emulsion that is used for the chemoembolization of hepatocellular carcinoma as a modifier of a nonviral gene transfer system for intraarterial gene delivery in experimentally induced hepatic tumors. MATERIALS AND METHODS: Experiments were performed in accordance with National Institutes of Health guidelines for the care and use of laboratory animals and were approved by the animal research committee at Seoul National University Hospital. VX2 carcinoma was implanted into the liver of 26 rabbits. Four nonviral gene transfer systems were prepared by using pCMV-luc+ as a reporter gene. The first system consisted of a DNA and polyethylenimine (PEI) complex (n = 7); the second, of a DNA and PEI complex mixed with iopamidol and iodized oil (n = 7); the third, of a DNA and PEI complex mixed with iopamidol (n = 7); and the fourth, of a DNA and PEI complex mixed with iodized oil (n = 5). For the DNA and PEI complex that was mixed with iopamidol and iodized oil, iopamidol was used to stabilize the emulsion. Twenty days after tumor implantation, intraarterial gene delivery was performed by selective catheterization of the hepatic artery. Rabbits were euthanized 24 hours after gene delivery. Luciferase activity was assayed in the tumor, left hepatic lobe, right hepatic lobe, and other organs and was statistically analyzed for comparison between complexes by using the Kruskal-Wallis test. RESULTS: Luciferase activity in the tumor was significantly higher for the group that received DNA, PEI, iopamidol, and iodized oil than for any other group (Kruskal-Wallis test, P < .05). Luciferase activity in the left hepatic lobe, right hepatic lobe, and other organs was not significantly different between complexes. Selective gene expression in tumor cells was confirmed by means of immunohistochemical analysis for luciferase. CONCLUSION: It is feasible to use an iodized oil emulsion system for the intratumoral transfection of nonviral vectors in experimentally induced hypervascular hepatic tumors.

Cell-permeable and biocompatible polymeric nanoparticles for apoptosis imaging.

Here, we report for the first time cell-permeable and biocompatible polymeric nanoparticles consisting of a polymer conjugated to a near-infrared (NIR) fluorescence (Cy5.5)-linked effector caspase-specific peptide. The close spatial proximity of the NIR fluorochromes in polymeric nanoparticles results in an autoquenched state, but polymer nanoparticles give rise to strong NIR fluorescence signal under apoptotic cells. Thus, the smart polymeric nanoparticle developed here is an attractive probe for real-time imaging of apoptosis in single cells.

Hydrophobically modified glycol chitosan nanoparticles as carriers for paclitaxel.

Self-assembled nanoparticles based on hydrophobically modified glycol chitosan (HGC) were prepared as a carrier for paclitaxel. HGC conjugates were prepared by chemically linking 5beta-cholanic acid to glycol chitosan chains using 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide chemistry. In phosphate-buffered saline (PBS; pH 7.4), the synthesized HGC conjugates formed nano-sized particles with a diameter of 200 nm and exhibited high thermodynamic stability as reflected by their low critical aggregation concentration (0.03 mg/ml). Paclitaxel was efficiently loaded into HGC nanoparticles up to 10 wt.% using a dialysis method. The paclitaxel-loaded HGC (PTX-HGC) nanoparticles were 400 nm in diameter and were stable in PBS for 10 days. These PTX-HGC nanoparticles also showed sustained release of the incorporated of paclitaxel (80% of the loaded dose was released in 8 days at 37 degrees C in PBS). Owing to sustained release, the PTX-HGC nanoparticles were less cytotoxic to B16F10 melanoma cells than free paclitaxel formulated in Cremophor EL. Injection of PTX-HGC nanoparticles into the tail vein of tumor-bearing mice prevented increases in tumor volume for 8 days. Finally, PTX was less toxic to the tumor-bearing mice when formulated in HGC nanoparticles than when formulated with Cremophor EL.

Self-assembled nanoparticles based on glycol chitosan bearing hydrophobic moieties as carriers for doxorubicin: in vivo biodistribution and anti-tumor activity.

Self-assembled nanoparticles, formed by polymeric amphiphiles, have been demonstrated to accumulate in solid tumors by the enhanced permeability and retention effect, following intravenous administration. In this study, hydrophobically modified glycol chitosans capable of forming nano-sized self-aggregates were prepared by chemical conjugation of fluorescein isothiocyanate or doxorubicin to the backbone of glycol chitosan. Biodistribution of self-aggregates (300 nm in diameter) was evaluated using tissues obtained from tumor-bearing mice, to which self-aggregates were systemically administered via the tail vein. Irrespective of the dose, a negligible quantity of self-aggregates was found in heart and lung, whereas a small amount (3.6-3.8% of dose) was detected in liver for 3 days after intravenous injection of self-aggregates. The distributed amount of self-aggregates gradually increased in tumor as blood circulation time increased. The concentration of self-aggregates in blood was as high as 14% of dose at 1 day after intravenous injection and was still higher than 8% even at 3 days. When self-aggregates loaded with doxorubicin were administered into the tumor-bearing mice via the tail vein, they exhibited lower toxicity than but comparable anti-tumor activity to free doxorubicin. These results revealed the promising potential of self-aggregates on the basis of glycol chitosan as a carrier for hydrophobic anti-tumor agents.

Bioadhesive drug delivery system using glyceryl monooleate for the intravesical administration of paclitaxel.

BACKGROUND: Many reports have shown that the efficacy of intravesical therapy for bladder cancer is in part limited by the poor penetration of drugs into the urothelium. The present study evaluated the effect of glyceryl monooleate (GMO) on the absorption of intravesically administered paclitaxel in a rabbit model of bladder cancer. METHODS: Urine, plasma, and tissue pharmacokinetics were determined in rabbits treated for 120 min with paclitaxel (500 microg/20 ml) by intravesical instillation. Two formulations of GMO/paclitaxel were evaluated using different proportions of water, 15 and 30%, and Taxol was used as a control. Animals were observed for clinical signs of toxicity and necropsy was performed. RESULTS: 120 min after instillation, the bladder was emptied and excised. In the urine, paclitaxel concentration was decreased by 39.6 and 41.2% in the two experimental groups and by 25.2% in the control group. The paclitaxel concentrations in the urothelium were 53 and 56% of the urine concentration in both experimental groups, but 11% in the control group. The concentration then declined exponentially in the underlying capillary-perfused tissues, reaching equilibrium at a depth of 1,400-1,700 microm. The plasma concentrations were extremely low compared with concentrations in urine and bladder tissues and were not associated with clinical toxicity. CONCLUSIONS: We conclude that GMO has a significantly increased bioadhesiveness to bladder mucosa. Therefore, intravesical administration of GMO/paclitaxel/water provides a significant advantage for drugs targeting the bladder tissue, and paclitaxel represents a viable option for intravesical bladder cancer therapy.

Airway gene transfer using cationic emulsion as a mucosal gene carrier.

BACKGROUND: Delivery of genes to airway mucosa would be a very valuable method for gene therapy and vaccination. However, there have been few reports on suitable gene delivery systems for administration. In this study, we use a cationic emulsion system, which is physically stable and facilitates the transfer of genes in the presence of up to 90% serum, as a mucosal gene carrier. METHODS AND RESULTS: Cationic lipid emulsion was formulated with squalene and 1,2-dioleoyl-sn-glycero-3-trimethylammoniumpropane (DOTAP) as major components. Emulsions formed stable complexes with DNA and protected and transferred DNA to target cells against DNase I digestion in the presence of mucosal destabilizers such as heparin sulfate (a polysaccharide of the glycosaminoglycan family in mucosa) and Newfectan (a natural lung extract of bovine) in an in vitro system. In contrast, commercial liposomes and counter liposomes, made with an identical lipid composition of emulsions, failed. After in vivo intranasal instillation, the cationic emulsion showed at least 200 times better transfection activity than the liposomal carriers in both nasal tissue and lung. CONCLUSIONS: These findings show that cationic emulsions can mediate gene transfection into airway epithelium, making it a good choice for transferring therapeutic genes and for genetic vaccination against an pathogenic infection via an airway route.

Polycations enhance emulsion-mediated in vitro and in vivo transfection.

To enhance the in vitro and in vivo transfection activity of the cationic lipid emulsion (LE), three natural polycations, protamine sulfate (PS), poly-L-lysine and spermine, were selected as DNA condensing active agents. Formation of the LE/polycation/DNA ternary complexes was identified by using agarose gel retardation study. The structure of these complexes was characterized by measuring the complex size and the decrease of the DNA fluorescence in the presence of ethidium bromide (EtBr). By adding a polycation, the particle size of the complex decreased, and DNA in the complex became highly condensed and resistant to intercalation of EtBr. Among the polycations, PS yielded the most highly compacted ternary complex. In vitro and in vivo transfection activities of the complexes were determined using various cell lines and Balb/c mouse intravenously and intranasally, respectively. The transfection activity of the ternary complex increases by at least 2.5-5-fold in vitro cell culture system in the presence of 80% serum as well as in vivo mouse system, as compared with LE/DNA binary complexes. More importantly, after intravenous and intranasal administrations, the in vivo transfection efficiency of the LE/PS/DNA complex was ca. 30 and 50 times higher than that of the liposome (LP)/DNA complex in spleen and lung, respectively. On the other hand, cell toxicity of the ternary complex is lower than that of binary complex. Thus, we conclude that the pre-condensation of DNA with polycations can be a promising approach to further increase in vitro and in vivo transfection efficiency of cationic lipid emulsion.

Self-assembled nanoparticles containing hydrophobically modified glycol chitosan for gene delivery.

A self-assembled nanoparticle was prepared using a hydrophobically modified glycol chitosan for gene delivery. A primary amine of glycol chitosan was modified with 5beta-cholanic acid to prepare a hydrophobically modified glycol chitosan (HGC). The modified chitosan spontaneously formed DNA nanoparticles by a hydrophobic interaction between HGC and hydrophobized DNA. As the HGC content increased, the encapsulation efficiencies of DNA increased while the size of HGC nanoparticles decreased. Upon increasing HGC contents, HGC nanoparticle became less cytotoxic. The increased HGC contents also facilitated endocytic uptakes of HGC nanoparticles by COS-1 cells, which were confirmed by a confocal microscopy. The HGC nanoparticles showed increasing in vitro transfection efficiencies in the presence serum. In vivo results also showed that the HGC nanoparticles had superior transfection efficiencies to naked DNA and a commercialized transfection agent. The HGC nanoparticles composed of hydrophobized DNA and hydrophobically modified glycol chitosan played a significant role in enhancing transfection efficiencies in vitro as well as in vivo.