Single Oral Gavage Research Articles

Enrofloxacin against Escherichia coli in turkeys: Which treatment scheme is effective?

The efficacy of enrofloxacin (ENRO) was evaluated against multidrug-resistant avian pathogenic Escherichia coli correlating the minimum inhibitory concentrations (MIC) of 235 E. coli field strains with its pharmacokinetics (PK) in 50 healthy turkeys (5 groups) with a PK/pharmacodynamic approach. The treatments were as follows: a) single oral gavage and b) single subcutaneous (SC) treatment at the recommended dose of 10 mg/kg; c) single oral gavage, d) 5 d of 10-h pulsed water medication, and e) 5 d of 24-h continuous water medication at the doubled dose of 20 mg/kg. Blood samples were collected at established times over 24 h. Plasma was analyzed using a liquid chromatography tandem mass spectrometry method that was validated in house. A monocompartmental and a noncompartmental model were applied to the data to obtain the PK results. After gavage administration, the mean maximum concentration Cmax/MIC50 and area under the curve AUC0–24/MIC50 ratios were, respectively, 3.07 ± 0.62 and 7.01 ± 1.03 and 25.48 ± 3.04 and 57.2 ± 3.73 for the 10 and 20 mg/kg doses, respectively. After SC administration of 10 mg/kg, Cmax/MIC50 and AUC0–24/MIC50 ratios were 3.45 ± 0.75 and 33.96 ± 7.46, respectively. After the administration of 10-h pulsed or 24-h continuous medicated water at 20 mg/kg, lower values of Cmax/MIC50 (10-h pulsed: 3.45 ± 0.7; 24-h continuous: 3.05 ± 0.48) and AUC0–24/MIC50 (10-h pulsed: 42.42 ± 6.17; 24-h continuous: 53.32 ± 5.55) were obtained. Based on these results, the European Union-recommended dosage of 10 mg/kg seems ineffective to achieve adequate drug plasma concentrations and even the 20 mg/kg by 10 h pulsed or continuous medicated water administration did not reach completely efficacious concentrations in plasma against colibacillosis. Although the results obtained were not completely encouraging, the medicated water should preferably be provided continuously. To conclude about the efficacy of ENRO treatment against colibacillosis, target tissue concentration should be extensively considered.

β-cypermethrin-induced acute neurotoxicity in the cerebral cortex of mice

A Type II pyrethroid pesticide β-cypermethrin is widely used in agriculture and domestic applications for pest control. However, the effect of β-cypermethrin on the glutamate neurotransmitter has not been well-documented. In the current study, mice were treated with 20, 40, or 80 mg/kg β-cypermethrin by a single oral gavage, with corn oil as a vehicle control. Four hours after treatment, we investigated glutamate levels and glutamate-metabolizing enzyme (phosphate-activated glutaminase, PAG; glutamine synthetase, GS) activities in the cerebral cortex of mice, using a HPLC system with ultraviolet detectors and a colorimetric assay. Glutamate uptake levels in the synaptosomes of cerebral cortex and mRNA expression levels of PAG, GS, and glutamate transporter-1 (GLT-1) in the cerebral cortex were detected by a radioactive labeling method and qRT-PCR, respectively. Toxic symptoms were observed in mice treated with 40 or 80 mg/kg β-cypermethrin. Compared with the control, significant decreases in glutamate level and GS activity, and an obvious increase in synaptosomal glutamate uptake, were found in the cerebral cortex of mice treated with 80 mg/kg β-cypermethrin. No significant changes were found among groups in PAG activity or PAG, GS, and GLT-1 mRNA expression levels. These results suggest that β-cypermethrin treatment may reduce the glutamate level in the mouse cerebral cortex, which is associated with decreased GS activity and increased synaptosomal glutamate uptake. Our findings provide a partial explanation for the neurotoxic effects of synthetic β-cypermethrin insecticides.

Acute Oral Safety Study of Sodium Caseinate Glycosylated via Maillard Reaction with Galactose in Rats

In order to potentially use sodium caseinate (SC) glycated with galactose (Gal) in the food industry as a new functional ingredient with proved technological and biological properties, an evaluation of oral acute toxicity has been carried out. An acute safety study with SC-Gal glycoconjugates in the Wistar rat with a single oral gavage dose of 2,000 mg/kg of body weight was conducted. The SC-Gal glycoconjugates were well tolerated; no adverse effects or mortality was observed during the 2-week observation period. No abnormal signs, behavioral changes, body weight changes, or alterations in food and water consumption occurred. After this period, no changes in hematological and serum chemistry parameters, organ weights, or gross pathology or histopathology were detected. It was concluded that SC-Gal glycoconjugates obtained via the Maillard reaction were well tolerated in rats at an acute oral dose of 2,000 mg/kg of body weight. The SC-Gal glycoconjugates have a low order of acute toxicity, and the oral 50 % lethal dose for male and female rats is in excess of 2,000 mg/kg of body weight.

Attenuation of γ-aminobutyric acid (GABA) transaminase activity contributes to GABA increase in the cerebral cortex of mice exposed to β-cypermethrin

The current study investigated the γ-aminobutyric acid (GABA) levels and GABA metabolic enzymes (GABA transaminase (GABA(T)) and glutamate decarboxylase (GAD)) activities at 2 and 4 h after treatment, using a high-performance liquid chromatography with ultraviolet detectors and colorimetric assay, in the cerebral cortex of mice treated with 20, 40 or 80 mg/kg β-cypermethrin by a single oral gavage, with corn oil as vehicle control. In addition, GABA protein (4 h after treatment), GABA(T) protein (2 h after treatment) and GABA receptors messenger RNA (mRNA) expression were detected by immunohistochemistry, Western blot and real-time quantitative reverse transcriptase polymerase chain reaction, respectively. β-Cypermethrin (80 mg/kg) significantly increased GABA levels in the cerebral cortex of mice, at both 2 and 4 h after treatment, compared with the control. Also, GABA immunohistochemistry results suggested that the number of positive granules was increased in the cerebral cortex of mice 4 h after exposure to 80 mg/kg β-cypermethrin when compared with the control. Furthermore, the results also showed that GABA(T) activity detected was significantly decreased in the cerebral cortex of mice 2 h after β-cypermethrin administration (40 or 80 mg/kg). No significant changes were found in GAD activity, or the expression of GABA(T) protein and GABAB receptors mRNA, in the cerebral cortex of mice, except that 80 mg/kg β-cypermethrin caused a significant decrease, compared with the vehicle control, in GABAA receptors mRNA expression 4 h after administration. These results suggested that attenuated GABA(T) activity induced by β-cypermethrin contributed to increased GABA levels in the mouse brain. The downregulated GABAA receptors mRNA expression is most likely a downstream event.

Toxicogenomic Evaluation of Long-term Hepatic Effects of TCDD in Immature, Ovariectomized C57BL/6 Mice

Acute exposure to hepatotoxic doses of 2,3,7,8-tetrachloro- dibenzo-p-dioxin (TCDD) in mice is characterized by differential gene expression that can be phenotypically anchored to elevated levels of serum alanine aminotransferase, increased relative liver weights, hepatic steatosis, inflammation, and hepatocellular necrosis. Unlike most studies that focus on acute exposure effects, this study evaluated the long-term effects of a single oral gavage of 30 μg/kg TCDD at 1, 4, 12, 24, 36, and 72 weeks postdose in ovariectomized C57BL/6 mice. Hepatic TCDD levels were almost completely eliminated by 24 weeks with a calculated half-life of 12 days. Hepatic gene expression analysis identified 395 unique differentially expressed genes between 1 and 12 weeks that decreased to ≤ 8 by 72 weeks, consistent with the minimal hepatic TCDD levels. Hepatic vacuolization, characteristic of short-term exposure, subsided by 4 weeks. Similarly, TCDD-elicited hepatic necrosis and inflammation dissipated by 1 week. Collectively, these results suggest that TCDD-elicited histologic and gene expression responses can be correlated to elevated hepatic TCDD levels, which, once eliminated, elicit minimal hepatic gene expression and histologic alterations.

Acute and Repeated Dose (28 Days) Oral Safety Studies of ALIBIRD in Rats

ALIBIRD, a test substance composed of oligosaccharides derived from lactulose, a hydrolysate of a whey protein concentrate, and a supercritical extract of rosemary (1:0.5:0.05), was prepared in the laboratory and evaluated for its safety as a multifunctional food additive. In oral toxicity studies (acute and 28 days repeated dose) using Wistar rats, ALIBIRD was administered in a single oral gavage dose of 2,000 mg/kg of body weight and resulted in no adverse events or mortality; a daily dose of 2,000 mg/kg of body weight for 28 days by gavage also resulted in no adverse effects or mortality. No abnormal clinical signs, behavioral changes, body weight changes, or changes in food and water consumption occurred in either study. There were no changes in hematological and serum chemistry values, organ weights, or gross or histological characteristics. Based on test results, it is concluded that ALIBIRD is well tolerated in rats at an acute and subchronic (28 days) dose of 2,000 mg/kg of body weight.

Integrated pharmacokinetics/pharmacodynamics parameters-based dosing guidelines of enrofloxacin in grass carp Ctenopharyngodon idella to minimize selection of drug resistance

BackgroundAntibiotic resistance has become a serious global problem and is steadily increasing worldwide in almost every bacterial species treated with antibiotics. In aquaculture, the therapeutic options for the treatment of A. hydrophila infection were only limited to several antibiotics, which contributed for the fast-speed emergence of drug tolerance. Accordingly, the aim of this study was to establish a medication regimen to prevent drug resistant bacteria. To determine a rational therapeutic guideline, integrated pharmacodynamics and pharmacokinetics parameters were based to predict dose and dosage interval of enrofloxacin in grass carp Ctenopharyngodon idella infected by a field-isolated A. hydrophila strain.ResultsThe pathogenic A. hydrophila strain (AH10) in grass carp was identified and found to be sensitive to enrofloxacin. The mutant selection window (MSW) of enrofloxacin on isolate AH10 was determined to be 0.5 - 3 μg/mL based on the mutant prevention concentration (MPC) and minimum inhibitory concentration (MIC) value. By using high-performance liquid chromatography (HPLC) system, the Pharmacokinetic (PK) parameters of enrofloxacin and its metabolite ciprofloxacin in grass carp were monitored after a single oral gavage of 10, 20, 30 μg enrofloxacin per g body weight. Dosing of 30 μg/g resulted in serum maximum concentration (Cmax) of 7.151 μg/mL, and concentration in serum was above MPC till 24 h post the single dose. Once-daily dosing of 30 μg/g was determined to be the rational choice for controlling AH10 infection and preventing mutant selection in grass carp. Data of mean residue time (MRT) and body clearance (CLz) indicated that both enrofloxacin and its metabolite ciprofloxacin present similar eliminating rate and pattern in serum, muscle and liver. A withdraw time of more than 32 d was suggested based on the drug eliminating rate and pharmacokinetic model described by a polyexponential equation.ConclusionsBased on integrated PK/PD parameters (AUC/MIC, Cmax/MIC, and T>MPC), the results of this study established a principle, for the first time, on drawing accurate dosing guideline for pharmacotherapy against A. hydrophila strain (AH10) for prevention of drug-resistant mutants. Our approach in combining PK data with PD parameters (including MPC and MSW) was the new effort in aquaculture to face the challenge of drug resistance by drawing a specific dosage guideline of antibiotics.

Comparative Analysis of Temporal and Dose-Dependent TCDD-Elicited Gene Expression in Human, Mouse, and Rat Primary Hepatocytes

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD)-elicited time- and dose-dependent differential gene expression was compared in human, mouse, and rat primary hepatocytes. Comprehensive time course (10 nM TCDD or dimethyl sulfoxide vehicle control for 1, 2, 4, 8, 12, 24, and 48h) studies identified 495, 2305, and 711 differentially expressed orthologous genes in human, mouse, and rat hepatocytes, respectively. However, only 16 orthologs were differentially expressed across all three species, with the majority of orthologs exhibiting species-specific expression (399 human, 2097 mouse, and 533 rat), consistent with species-specific expression reported in other in vitro and in vivo comparative studies. TCDD also elicited the dose-dependent induction of 397 human, 100 mouse, and 443 rat genes at 12h and 615 human, 426 mouse, and 314 rat genes at 24h. Comparable EC50 values were obtained for AhR battery genes including Cyp1a1 (0.1 nM human, 0.05 nM mouse, 0.08 nM rat at 24h) and Tiparp (0.97 nM human, 0.63 nM mouse, 0.14 nM rat at 12h). Overrepresented functions and pathways included amino acid metabolism in humans, immune response in mice, and energy homeostasis in rats. Differentially expressed genes functionally associated with lipid transport, processing, and metabolism were overrepresented in all three species but exhibited species-specific expression consistent with the induction of hepatic steatosis in mice but not in rats following a single oral gavage of TCDD. Furthermore, human primary hepatocytes showed lipid accumulation following 48h of treatment with TCDD, suggesting that AhR-mediated steatosis in mice more closely resembles human hepatic fat accumulation compared with that in rats. Collectively, these results suggest that species-specific gene expression profiles mediate the species-specific effects of TCDD despite the conservation of the AhR and its signaling mechanism.

Comparison of TCDD-elicited genome-wide hepatic gene expression in Sprague–Dawley rats and C57BL/6 mice

Although the structure and function of the AhR are conserved, emerging evidence suggests that downstream effects are species-specific. In this study, rat hepatic gene expression data from the DrugMatrix database (National Toxicology Program) were compared to mouse hepatic whole-genome gene expression data following treatment with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). For the DrugMatrix study, male Sprague–Dawley rats were gavaged daily with 20μg/kg TCDD for 1, 3 and 5days, while female C57BL/6 ovariectomized mice were examined 1, 3 and 7days after a single oral gavage of 30μg/kg TCDD. A total of 649 rat and 1386 mouse genes (|fold change|≥1.5, P1(t)≥0.99) were differentially expressed following treatment. HomoloGene identified 11,708 orthologs represented across the rat Affymetrix 230 2.0 GeneChip (12,310 total orthologs), and the mouse 4×44K v.1 Agilent oligonucleotide array (17,578 total orthologs). Comparative analysis found 563 and 922 orthologs differentially expressed in response to TCDD in the rat and mouse, respectively, with 70 responses associated with immune function and lipid metabolism in common to both. Moreover, QRTPCR analysis of Ceacam1, showed divergent expression (induced in rat; repressed in mouse) functionally consistent with TCDD-elicited hepatic steatosis in the mouse but not the rat. Functional analysis identified orthologs involved in nucleotide binding and acetyltransferase activity in rat, while mouse-specific responses were associated with steroid, phospholipid, fatty acid, and carbohydrate metabolism. These results provide further evidence that TCDD elicits species-specific regulation of distinct gene networks, and outlines considerations for future comparisons of publicly available microarray datasets.

Mouse Liver Protein Sulfhydryl Depletion after Acetaminophen Exposure

Acetaminophen (APAP)-induced liver injury is the leading cause of acute liver failure in many countries. This study determined the extent of liver protein sulfhydryl depletion not only in whole liver homogenate but also in the zonal pattern of sulfhydryl depletion within the liver lobule. A single oral gavage dose of 150 or 300 mg/kg APAP in B6C3F1 mice produced increased serum alanine aminotransferase levels, liver necrosis, and glutathione depletion in a dose-dependent manner. Free protein sulfhydryls were measured in liver protein homogenates by labeling with maleimide linked to a near infrared fluorescent dye followed by SDS-polyacrylamide gel electrophoresis. Global protein sulfhydryl levels were decreased significantly (48.4%) starting at 1 hour after the APAP dose and maintained at this reduced level through 24 hours. To visualize the specific hepatocytes that had reduced protein sulfhydryl levels, frozen liver sections were labeled with maleimide linked to horseradish peroxidase. The centrilobular areas exhibited dramatic decreases in free protein sulfhydryls while the periportal regions were essentially spared. These protein sulfhydryl-depleted regions correlated with areas exhibiting histopathologic injury and APAP binding to protein. The majority of protein sulfhydryl depletion was due to reversible oxidation since the global- and lobule-specific effects were essentially reversed when the samples were reduced with tris(2-carboxyethy)phosphine before maleimide labeling. These temporal and zonal pattern changes in protein sulfhydryl oxidation shed new light on the importance that changes in protein redox status might play in the pathogenesis of APAP hepatotoxicity.

469 Fingolimod (Gilenya®), a New Oral Treatment for Relapsing Forms of Multiple Sclerosis, Causes Bradycardia and Prolongs the QTC Interval

Fingolimod hydrochloride (Gilenya®) is a new oral agent that was approved on March 9 2011 by Health Canada for treating relapsing forms of Multiple Sclerosis (MS) in adults. Fingolimod is used to reduce the frequency of flare-ups (clinical exacerbations) and delay physical disability. It is a sphingosine 1-phosphate receptor modulator that reduces the migration of autoagressive lymphocytes into the CNS. Interestingly, as of February 27 2012, eleven fingolimod-associated sudden deaths have been reported internationally. Four of these 11 reports involved serious heart-related events including one severe cardiac arrhythmia. A patient in the United States died within 24 hours of taking its first dose. Of note, as specified in the product labelling, QTc interval prolongation has been reported during clinical studies with fingolimod. Our aim was to evaluate the effects of fingolimod on cardiac electrophysiology. 1) Ex vivo Langendorff retroperfusion experiments: Isolated hearts from male Hartley guinea pigs (n=4) were either let at their natural sinus rhythm (SR) or paced at basic cycle lengths (BCL) of 250 or 200 ms. They were allowed to stabilize and were then exposed for 15 minutes to fingolimod 10 or 100 nmol/L to assess drug-induced effect on monophasic action potential duration measured at 90% repolarization (MAPD90). 2) In vivo wireless cardiac telemetry experiments: Guinea pigs (n=4) implanted with radio transmitters were administered a single oral gavage dose of fingolimod 0.0625 mg/kg and 24h ECG recordings were made. See table.Tabled 1 Previous clinical studies have shown steady-state plasma concentrations of fingolimod of ≈11 nmol/L at a standard dose of 0.5 mg/day. In the present study, fingolimod had no significant ex vivo effect on MAPD90 at clinically relevant concentrations (10-100 nmol/L). However, in vivo, the drug caused significant prolongations of the RR, QT and QTc intervals. A trend towards PR prolongation was also observed. Interestingly, reversible AV blocks were observed in 4/4 of the animals after a single oral administration of fingolimod. When used at recommended dose, fingolimod may therefore increase the risk for severe arrhythmias, including life-threatening torsades de pointes, thus explaining cases of cardiac sudden deaths.

Perforated dried blood spot accurate microsampling: the concept and its applications in toxicokinetic sample collection

Dried blood spot (DBS) sampling has gained considerable interest as a microsampling technique to support drug discovery and development owing to its enormous ethical and practical benefits. Quantitative determinations of drugs and/or their metabolites collected in DBS matrix in its current format, however, have encountered technical challenges and regulatory uncertainty. The challenges of DBS bioanalysis are largely ascribed to the way how samples are collected and analyzed. Currently, an uncontrolled amount of a blood sample, e.g. 20 µl, is collected per time point per sample and spotted onto cellulose paper. Quantitation is based on removal of a fixed area of the DBS sample, resulting in sample waste, a need for mechanical punching and concomitant potential punching carryover, uncertainty in recovery assessment and the adverse impact of hematocrit on accurate quantitation. Here, we describe the concept and applications of a novel concept, namely perforated dried blood spot (PDBS), for accurate microsampling that addresses previous challenges. Advantages of PDBS are enumerated and compared with conventional DBS in the context of microsampling and liquid chromatography tandem mass spectrometry bioanalysis. Two approaches for accurate microsampling of a small volume of blood (5 µl) are proposed and demonstrated, i.e. Microsafe® pipettes and the Drummond incremental pipette. Two online sample enrichment techniques to enhance liquid chromatography tandem mass spectrometry sensitivity for microsampling bioanalysis are discussed. The PDBS concept was successfully applied for accurate sample collection (5 µl) in a toxicokinetic study in rats given a single oral gavage dose of acetaminophen. Perspectives on bioanalytical method validation for regulated DBS/PDBS microsampling are also presented.

Patterns of early gut colonization shape future immune responses of the host.

The most important trigger for immune system development is the exposure to microbial components immediately after birth. Moreover, targeted manipulation of the microbiota can be used to change host susceptibility to immune-mediated diseases. Our aim was to analyze how differences in early gut colonization patterns change the composition of the resident microbiota and future immune system reactivity. Germ-free (GF) mice were either inoculated by single oral gavage of caecal content or let colonized by co-housing with specific pathogen-free (SPF) mice at different time points in the postnatal period. The microbiota composition was analyzed by denaturing gradient gel electrophoresis for 16S rRNA gene followed by principal component analysis. Furthermore, immune functions and cytokine concentrations were analyzed using flow cytometry, ELISA or multiplex bead assay. We found that a single oral inoculation of GF mice at three weeks of age permanently changed the gut microbiota composition, which was not possible to achieve at one week of age. Interestingly, the ex-GF mice inoculated at three weeks of age were also the only mice with an increased pro-inflammatory immune response. In contrast, the composition of the gut microbiota of ex-GF mice that were co-housed with SPF mice at different time points was similar to the gut microbiota in the barrier maintained SPF mice. The existence of a short GF postnatal period permanently changed levels of systemic regulatory T cells, NK and NKT cells, and cytokine production. In conclusion, a time window exists that enables the artificial colonization of GF mice by a single oral dose of caecal content, which may modify the future immune phenotype of the host. Moreover, delayed microbial colonization of the gut causes permanent changes in the immune system.

Iloperidone (Fanapt®), a novel atypical antipsychotic, is a potent HERG blocker and delays cardiac ventricular repolarization at clinically relevant concentration

QT interval prolongation on the electrocardiogram (ECG) has extensively been reported with iloperidone, a novel antipsychotic drug. The objective of the present study was to evaluate the effects of iloperidone on cardiac ventricular repolarization at three different levels; in vitro, ex vivo and in vivo. (1) In vitro level: whole-cell patch-clamp experiments were performed on HERG-transfected HEK293 cells exposed to iloperidone 0.01–1μmol/L (n=35cells, total) to assess drug effect on HERG current. (2) Ex vivo level: Langendorff retroperfusion experiments were performed on isolated hearts from male Hartley guinea pigs (n=7) exposed to iloperidone 100nmol/L with/without chromanol 293B 10μmol/L to assess drug-induced prolongation of monophasic action potential duration measured at 90% repolarization (MAPD90). (3) In vivo level: ECG recordings using wireless cardiac telemetry were performed in guinea pigs (n=5) implanted with radio transmitters and treated with a single oral gavage dose of iloperidone 3mg/kg. (1) Patch-clamp experiments revealed an estimated IC50 for iloperidone on HERG current of 161±20nmol/L. (2) While pacing the hearts at stimulation cycle lengths of 200 or 250ms, or during natural sinus rhythm (no external pacing), iloperidone 100nmol/L prolonged MAPD90 by respectively 9.2±0.9, 11.2±1.6 and 21.4±2.3ms. After adding chromanol 293B, MAPD90 was further prolonged by 7.3±3.3, 11.5±2.3 and 29.2±6.7ms, respectively. (3) Iloperidone 3mg/kg p.o. caused a maximal 42.7±10.2ms prolongation of corrected QT interval (QTcF), 40min after administration. Iloperidone prolongs the QT interval, the cardiac action potentials and is a potent HERG blocker. Patients are at increased risk of cardiac proarrhythmia during iloperidone treatment, as this drug possesses significant cardiac repolarization-delaying properties at clinically relevant concentration.

Tofogliflozin, a Potent and Highly Specific Sodium/Glucose Cotransporter 2 Inhibitor, Improves Glycemic Control in Diabetic Rats and Mice

Sodium/glucose cotransporter 2 (SGLT2) is the predominant mediator of renal glucose reabsorption and is an emerging molecular target for the treatment of diabetes. We identified a novel potent and selective SGLT2 inhibitor, tofogliflozin (CSG452), and examined its efficacy and pharmacological properties as an antidiabetic drug. Tofogliflozin competitively inhibited SGLT2 in cells overexpressing SGLT2, and K(i) values for human, rat, and mouse SGLT2 inhibition were 2.9, 14.9, and 6.4 nM, respectively. The selectivity of tofogliflozin toward human SGLT2 versus human SGLT1, SGLT6, and sodium/myo-inositol transporter 1 was the highest among the tested SGLT2 inhibitors under clinical development. Furthermore, no interaction with tofogliflozin was observed in any of a battery of tests examining glucose-related physiological processes, such as glucose uptake, glucose oxidation, glycogen synthesis, hepatic glucose production, glucose-stimulated insulin secretion, and glucosidase reactions. A single oral gavage of tofogliflozin increased renal glucose clearance and lowered the blood glucose level in Zucker diabetic fatty rats. Tofogliflozin also improved postprandial glucose excursion in a meal tolerance test with GK rats. In db/db mice, 4-week tofogliflozin treatment reduced glycated hemoglobin and improved glucose tolerance in the oral glucose tolerance test 4 days after the final administration. No blood glucose reduction was observed in normoglycemic SD rats treated with tofogliflozin. These findings demonstrate that tofogliflozin inhibits SGLT2 in a specific manner, lowers blood glucose levels by increasing renal glucose clearance, and improves pathological conditions of type 2 diabetes with a low hypoglycemic potential.

Comparing anti-hyperglycemic activity and acute oral toxicity of three different trivalent chromium complexes in mice

Three different ligands (rutin, folate and stachyose) of chromium(III) complexes were compared to examine whether they have similar effect on anti-hyperglycemic activity as well as the acute toxicity status. Anti-hyperglycemic activities of chromium rutin complex (CrRC), chromium folate complex (CrFC) and chromium stachyose complex (CrSC) were examined in alloxan-induced diabetic mice with daily oral gavage for a period of 2weeks at the dose of 0.5–3.0mg Cr/kg. Acute toxicities of CrRC and CrFC were tested using ICR mice at the dose of 1.0–5.0g/kg with a single oral gavage and observed for a period of 2weeks. Biological activities results indicated that only CrRC and CrFC could decrease blood glucose level, reduce the activities of aspartate transaminase, alanine transaminase, alkaline phosphatase, and increase liver glycogen level. In acute toxicity study, LD50 values for both CrRC and CrFC were above 5.0g/kg. The minimum lethal dose for CrFC was above 5.0g/kg, while that for CrRC was 1.0g/kg. Anti-diabetic activity of those chromium complexes was not similar and their acute toxicities were also different. CrFC represent an optimal chromium supplement among those chromium complexes with potential therapeutic value to control blood glucose in diabetes and non-toxicity in acute toxicity.

Enhanced Anti-Diabetic Activity of a Combination of Chromium(III) Malate Complex and Propolis and its Acute Oral Toxicity Evaluation

In order to obtain the additional benefit of anti-diabetic activity and protective effects of liver injury for diabetes, the anti-diabetic effect and acute oral toxicity of a combination of chromium(III) malate complex (Cr(2)(LMA)(3)) and propolis were assessed. The anti-diabetic activity of the combination of the Cr(2)LMA(3) and propolis was compared with Cr(2)(LMA)(3) and propolis alone in alloxan-induced diabetic mice by daily oral gavage for a period of 2 weeks. Acute oral toxicity of the combination of the Cr(2)LMA(3) and propolis was tested using ICR mice at the dose of 1.0-5.0 g/kg body mass by a single oral gavage and observed for a period of 2 weeks. The results of the anti-diabetic activity of the combination from the aspects of blood glucose level, liver glycogen level, and the activities of aspartate transaminase, alanine transaminase, and alkaline phosphatase indicated that the increased anti-diabetic activity and the protective efficacy of liver injury for diabetes were observed. In acute toxicity study, LD(50) (median lethal dose) value for the combination was greater than 5.0 g/kg body mass. The combination of Cr(2)LMA(3) and propolis might represent the nutritional supplement with potential therapeutic value to control blood glucose and exhibit protective efficacy of liver injury for diabetes and non-toxicity in acute toxicity.

Effects of Berberine and Hwangryunhaedok-Tang on Oral Bioavailability and Pharmacokinetics of Ciprofloxacin in Rats

Hwangryunhaedok-Tang (HR) and berberine-containing single herbs are used to treat bacterial infection and inflammatory diseases in eastern Asia. The combination of berberine-containing herbal medicines and ciprofloxacin can be an excellent antibacterial chemotherapy against multidrug resistance bacteria. To evaluate the pretreatment effect of berberine and HR, vehicle, berberine (25 and 50 mg/kg/day), and HR (1.4 g/kg/day) were daily administered to rats for five consecutive days. On day 6, ciprofloxacin was administered (10 mg/kg, i.v. and 20 mg/kg, p.o.) to rats. To assess cotreatment effect of berberine and ciprofloxacin, berberine (50 mg/kg) and ciprofloxacin (20 mg/kg) were coadministered by single oral gavage. Pharmacokinetic data were estimated by noncompartmental model. Compared with ciprofloxacin alone (control group), coadministration of berberine (50 mg/kg) and ciprofloxacin significantly decreased C max of ciprofloxacin (P < 0.05). In addition, the pretreatment of berberine (50 mg/kg/day) and HR (1.4 g/kg/day) significantly decreased C max and AUC0→∞, compared with control group (P < 0.05). The oral bioavailability of ciprofloxacin was reduced by cotreatment of berberine and pretreatment of berberine and HR. Our results suggest that the expression of P-glycoprotein and organic anion and/or organic cation transporters (OAT/OCT) could take a role in reduced oral bioavailability of ciprofloxacin by berberine and HR.

Pharmacokinetics and Tissue Distribution of Norfloxacin in Eel Following Oral Gavage

The pharmacokinetics of norfloxacin were investigated in the European eel after a single oral gavage of 10 mg norfloxacin per kg body weight. The concentrations of norfloxacin in the main tissues (kidney, muscle, hepatopancreas and blood) were simultaneously detected by HPLC. All of the concentration-time curves of norfloxacin in the plasma, muscle and liver were consistent with absorption of a two-compartment open kinetic model. Norfloxacin was widely distributed in different tissues in the European eel. Apparent volume of distribution (Vd) was 52.025 L/kg, 34.589 L/kg, 2.795 L/kg, and 0.969 L/kg, in plasma, muscle, liver and kidney, respectively. Norfloxacin in the eel was proved to eliminate slowly, and half-time (tβ1/2) in plasma, muscle, liver and kidney, was 201.222 h, 123.789 h, 120.634 h and 627473.495 h, respectively. Body clearance was 0.689 L / ( kg•h ), 1.793 L/( kg•h ), 0.097 L/( kg•h ) and 0.028 L /( kg•h ), in plasma, muscle, liver and kidney, respectively.

Pharmacokinetics and Tissue Distribution of Norfloxacin in Eel Following Oral Gavage

The pharmacokinetics of norfloxacin were investigated in the European eel after a single oral gavage of 10 mg norfloxacin per kg body weight. The concentrations of norfloxacin in the main tissues (kidney, muscle, hepatopancreas and blood) were simultaneously detected by HPLC. All of the concentration-time curves of norfloxacin in the plasma, muscle and liver were consistent with absorption of a two-compartment open kinetic model. Norfloxacin was widely distributed in different tissues in the European eel. Apparent volume of distribution (Vd) was 52.025 L/kg, 34.589 L/kg, 2.795 L/kg, and 0.969 L/kg, in plasma, muscle, liver and kidney, respectively. Norfloxacin in the eel was proved to eliminate slowly, and half-time (tβ1/2) in plasma, muscle, liver and kidney, was 201.222 h, 123.789 h, 120.634 h and 627473.495 h, respectively. Body clearance was 0.689 L / ( kg•h ), 1.793 L/( kg•h ), 0.097 L/( kg•h ) and 0.028 L /( kg•h ), in plasma, muscle, liver and kidney, respectively.