Plasma concentrations of fenbendazole (FBZ) and oxfendazole in alpacas (Lama pacos) after single intravenous and oral dosing of FBZ

The objective of this study was to determine plasma pharmacokinetics and bioavailability of fenbendazole (FBZ) and oxfendazole (OFZ) after intravenous (iv) and oral administrations of FBZ (5 mg/kg) to alpacas. Plasma concentrations of FBZ and OFZ after administration of FBZ iv and orally (5 mg/kg) were determined by high-performance liquid chromatography with ultraviolet detection. Total clearance (CL) of FBZ was 16.5±4 mL/kg/min (range: 4–31 mL/kg/min), and steady-state volume of distribution (Vd_ss) was 3.3±1 L/kg (range: 1.7–7.4 L/kg). The terminal phase half-life of FBZ after iv administration was 5.9±3.8 hours (range: 0.8–20 hours). After oral administration, the FBZ terminal phase half-life was 23±5 hours (range: 9–37 hours) and the systemic bioavailability of FBZ was 16%±6% (range: 1%–41%). Peak FBZ concentrations after oral administration were 0.13±0.05 µg/mL (range: 0.05–0.28 µg/mL) at 10 hours (range: 8–12 hours). Peak plasma OFZ concentrations after oral dosing with FBZ (5 mg/kg) were 0.14±0.05 µg/mL (0.05–0.3 µg/mL) at 24±7 hours (range: 12–48 hours). FBZ clearance is lower in comparison to that of other species. Systemic availability of FBZ after oral administration is low after oral dosing. Metabolites of FBZ produced by alpacas are similar to those observed in other species.

Toxicity of anthelmintic drugs (fenbendazole and flubendazole) to aquatic organisms

Flubendazole (FLU) and fenbendazole (FEN) belong to benzimidazoles-pharmaceuticals widely used in veterinary and human medicine for the treatment of intestinal parasites as well as for the treatment of systemic worm infections. In recent years, usage of these drugs increased, which resulted in a larger contamination of the environment and possible negative effects on biota. Hence, in our research, we investigated an aquatic ecotoxicity of these pharmaceuticals towards: marine bacteria (Vibrio fischeri), green algae (Scenedesmus vacuolatus), duckweed (Lemna minor) and crustacean (Daphnia magna). Ecotoxicity tests were combined with chemical analysis in order to investigate the actual exposure concentration of the compounds used in the experiment as well as to stability and adsorption studies. As a result, study evaluating sensitivity of different aquatic organisms to these compounds and new ecotoxicological data is presented. The strongest negative impact of FLU and FEN was observed to D. magna.

Screening for anthelmintic resistance in equid strongyles (Nematoda) in Romania

Resistance to anthelmintic medication of equid strongyles is a worldwide phenomenon and for this reason systematic investigations of resistant parasite populations are necessary. The purpose of the present study was to investigate the presence and distribution of equid strongyles resistant to the anthelmintics used in Romania, as well as the pre-treatment and post-treatment prevalence of species of strongylid nematodes. The Faecal Egg Count Reduction Test was performed between 2010 and 2013 on a total number of 588 horses and 23 donkeys from 26 locations (subgroups). Animals of the first group (I) consisting of subgroups no. 1-11 were treated with Albendazole (ABZ), those of the second group (II) consisting of subgroups no. 12-23 with Fenbendazole (FBZ), while Ivermectin (IVM) was used on animals of the third group (III) consisting of subgroups no. 24-26. Resistant strongyles have been found in 82% (average lower limit of the 95% confidence interval, LCL95%, was 65) of the total equids from the group treated with ABZ. In the group of horses treated with FBZ, resistant strongyles were identified in 75% of the subgroups (LCL95% = 44). No resistant strongyles have been identified in IVM-treated horse groups (LCL95% = 98). The pre-treatment prevalence of the species of the Strongylinae Müller, 1780 was 22%, whereas that with nematodes of the subfamily Cyathostominae Molin, 1861 78%. Post-treatment reduction of strongyline nematodes was observed (5%), which demonstrates the sensitivity of large strongyles to common anthelmintics. The post-treatment prevalence of cyathostomes was of 95%, which proves their resistance, especially to ABZ- and FBZ-based anthelmintics.

Development of a two-step high-resolution melting (HRM) analysis for screening sequence variants associated with resistance to the QoIs, benzimidazoles and dicarboximides in airborne inoculum of Botrytis cinerea

A rapid, high-resolution melting (HRM) analysis protocol was developed to detect sequence variations associated with resistance to the QoIs, benzimidazoles and dicarboximides in Botrytis cinerea airborne inoculum. HRM analysis was applied directly in fungal DNA collected from air samplers with selective medium. Three and five different genotypes were detected and classified according to their melting profiles in BenA and bos1 genes associated with resistance to benzimidazoles and dicarboximides, respectively. The sensitivity of the methodology was evident in the case of the QoIs, where genotypes varying either by a single nucleotide polymorphism or an additional 1205-bp intron were separated accurately with a single pair of primers. The developed two-step protocol was completed in 82 min and showed reduced variation in the melting curves' formation. HRM analysis rapidly detected the major mutations found in greenhouse strains providing accurate data for successfully controlling grey mould.

Benzimidazoles: novel mycobacterial gyrase inhibitors from scaffold morphing

Type II topoisomerases are well conserved across the bacterial species, and inhibition of DNA gyrase by fluoroquinolones has provided an attractive option for treatment of tuberculosis (TB). However, the emergence of fluoroquinolone-resistant strains of Mycobacterium tuberculosis (Mtb) poses a threat for its sustainability. A scaffold hopping approach using the binding mode of novel bacterial topoisomerase inhibitors (NBTIs) led to the identification of a novel class of benzimidazoles as DNA gyrase inhibitors with potent anti-TB activity. Docking of benzimidazoles to a NBTI bound crystal structure suggested that this class of compound makes key contacts in the enzyme active site similar to the reported NBTIs. This observation was further confirmed through the measurement of DNA gyrase inhibition, and activity against Mtb strains harboring mutations that confer resistance to aminopiperidines based NBTIs and Mtb strains resistant to moxifloxacin. Structure-activity relationship modification at the C-7 position of the left-hand side ring provided further avenue to improve hERG selectivity for this chemical series that has been the major challenges for NBTIs.

Facile and efficient one-pot synthesis of benzimidazoles using lanthanum chloride

BACKGROUND

We report the synthesis of benzimidazoles using lanthanum chloride as an efficient catalyst. One-pot synthesis of 2-substituted benzimidazole derivatives from o-phenylenediamine and a variety of aldehydes were developed under mild reaction conditions.

RESULTS

We have examined the effect of different solvents using the same reaction conditions. The yield of the product varied with the nature of the solvents, and better conversion and easy isolation of products were found with acetonitrile. In a similar manner, the reaction with o-phenylenediamine and 3,4,5-trimethoxybenzaldehyde was carried out without any solvents. The observation shows that the reaction was not brought into completion, even after starting for a period of 9 h, and the reaction mixture showed a number of spots in thin-layer chromatography.

CONCLUSIONS

In conclusion, lanthanum chloride has been employed as a novel and efficient catalyst for the synthesis of benzimidazoles in good yields from o-phenylenediamine and a wide variety of aldehydes. All of the reactions were carried out in the presence of lanthanum chloride (10 mol%) in acetonitrile at room temperature.

Synthesis and Anti-inflammatory Evaluation of Novel Benzimidazole and Imidazopyridine Derivatives

Sepsis, an acute inflammatory disease, remains the most common cause of death in intensive care units. A series of benzimidazole and imidazopyridine derivatives were synthesized and screened for anti-inflammatory activities, and the imidazopyridine series showed excellent inhibition of the expression of inflammatory cytokines in LPS-stimulated macrophages. Compounds X10, X12, X13, X14, and X15 inhibited TNF-α and IL-6 release in a dose-dependent manner, and X12 showed no cytotoxicity in hepatic cells. Furthermore, X12 exhibited a significant protection against LPS-induced septic death in mouse models. Together, these data present a series of new imidazopyridines with potential therapeutic effects in acute inflammatory diseases.

Influence of Alternative Tubulin Inhibitors on the Potency of a Epirubicin-Immunochemotherapeutic Synthesized with an Ultra Violet Light-Activated Intermediate: Influence of incorporating an internal/integral disulfide bond structure and Alternative Tubulin/Microtubule Inhibitors on the Cytotoxic Anti-Neoplastic Potency of Epirubicin-(C3-amide)-Anti-HER2/neu Synthesized Utilizing a UV-Photoactivated Anthracycline Intermediate

Immunochemotherapeutics, epirubicin-(C₃-amide)-SS-[anti-HER2/neu] with an internal disulfide bond, and epirubicin-(C₃-amide)-[anti-HER2/neu] were synthesized utilizing succinimidyl 2-[(4,4'-azipentanamido) ethyl]-1,3'-dithioproprionate or succinimidyl 4,4-azipentanoate respectively. Western blot analysis was used to determine the presence of any immunoglobulin fragmentation or IgG-IgG polymerization. Retained HER2/neu binding characteristics of epirubicin-(C₃-amide)-[anti-HER2/neu] and epirubicin-(C₃-amide)-SS-[anti-HER2/neu] were validated by cell-ELISA using a mammary adenocarcinoma (SKBr-3) population that highly over-expresses trophic HER2/neu receptor complexes. Cytotoxic anti-neoplastic potency of epirubicin-(C₃-amide)-[anti-HER2/neu] and epirubicin-(C₃-amide)-SS-[anti-HER2/neu] between epirubicin-equivalent concentrations of 10^-10 M and 10^-6 M was determined by measuring the vitality/proliferation of chemotherapeutic-resistant mammary adenocarcinoma (SKBr-3 cell type). Cytotoxic anti-neoplastic potency of benzimidazoles (albendazole, flubendazole, membendazole) and griseofulvin were assessed between 0-to-2 μg/ml and 0-to-100 μg/ml respectively while mebendazole and griseofulvin were analyzed at fixed concentrations of 0.35 μg/ml and 35 g/ml respectively in dual combination with gradient concentrations of epirubicin-(C₃-amide)-[anti-HER2/neu] and epirubicin-(C₃-amide)-SS-[anti-HER2/neu]. Cytotoxic anti-neoplastic potency for epirubicin-(C₃-amide)-[anti-HER2/neu] and epirubicin-(C₃-amide)-SS-[anti-HER2/neu] against chemotherapeutic-resistant mammary adenocarcinoma (SKBr-3) was nearly identical at epirubicin-equivalent concentrations of 10^-10 M and 10^-6 M. The benzimadazoles also possessed cytotoxic anti-neoplastic activity with flubendazole and albendazole being the most and least potent respectively. Similarly, griseofulvin had cytotoxic anti-neoplastic activity and was more potent than methylselenocysteine. Both mebendazole and griseofulvin when applied in dual combination with either epirubicin-(C₃-amide)-[anti-HER2/neu] or epirubicin-(C₃-amide)-SS-[anti-HER2/neu] produced enhanced levels of cytotoxic anti-neoplatic potency.

Combined Pd/C and Montmorillonite Catalysis for One-Pot Synthesis of Benzimidazoles

A series of nineteen benzimidazoles are prepared from ortho-nitroanilines via one-pot transfer hydrogenation, condensation, and dehydrogenation enabled by the concurrent use of two heterogeneous catalysts: montmorillonite-K10 and Pd/C. This strategy is further employed to accomplish a five-step, three-component synthesis of an antifungal benzimidazoquinazoline using a simple one-pot procedure.

Benzimidazoles as Potent and Orally Active mGlu5 Receptor Antagonists with an Improved PK Profile

A focused chemical optimization effort of compound 1 based on metabolite elucidation is described, resulting in 15i, a highly potent and selective mGlu5 receptor antagonist with an improved pharmacokinetic profile compared to 1. Characterization of 15i in vivo in the fear-potentiated startle (FPS) paradigm revealed a robust reduction of conditioned fear behavior. This effect nicely correlates with the rat brain pharmacokinetics.

Synthesis, characterization, and biological evaluation of benzimidazole derivatives as potential anxiolytics

The synthesized benzimidazoles compounds were prepared from the condensation reaction between o-Phenylenediamine and various carbonyl compounds, in the presence of ammonium chloride as a catalyst. Ammonium chloride is a commercial and environmentally benign catalyst. The yield of all benzimidazole derivatives was found to be in the range of 75 - 94%. The purity of the compounds was ascertained by melting point and TLC. The synthesized compounds were characterized by using IR,(1)H NMR, and MASS spectral data together with elemental analysis. The synthesized benzimidazole compounds were screened for acute and chronic anti-anxiety activity in Wistar rats by using an elevated plus maze model with standard Diazepam. The synthesized compounds Z(B), Z(E), Z(F), Z(G), and Z(H) showed potent anti-anxiety activity when compared to the standard Diazepam. The compound Z(H) exhibited a higher anti-anxiety activity when compared to other prepared benzimidazoles. The results were subjected to statistical analysis by using one-way ANOVA followed by the Tukey-Kramer test, to calculate the significance.

Direct thrombin inhibitors versus vitamin K antagonists or low molecular weight heparins for prevention of venous thromboembolism following total hip or knee replacement

BACKGROUND

Patients who have undergone total hip or knee replacement (THR, TKR) have a high risk of developing venous thromboembolism (VTE) following surgery, despite appropriate anticoagulation with warfarin or low molecular weight heparin (LMWH). New anticoagulants are under investigation.

OBJECTIVES

To examine the efficacy and safety of prophylactic anticoagulation with direct thrombin inhibitors (DTIs) versus LMWH or vitamin K antagonists in the prevention of VTE in patients undergoing THR or TKR.

SEARCH STRATEGY

The Cochrane Peripheral Vascular Disease Group searched their Specialized Register (last searched 12 March 2010) and CENTRAL (last searched 2010, Issue 2).

SELECTION CRITERIA

Randomised controlled trials.

DATA COLLECTION AND ANALYSIS

Three reviewers independently assessed methodological quality and extracted data in pre-designed tables. The reported follow-up events were included

MAIN RESULTS

We included 14 studies included involving 21,642 patients evaluated for efficacy and 27,360 for safety. No difference was observed in major VTE in DTIs compared with LMWH in both types of operations (odds ratio (OR) 0.91; 95% confidence interval (CI) 0.69 to 1.19), with high heterogeneity (I(2) 71%). No difference was observed with warfarin (OR 0.85; 95% CI 0.63 to 1.15) in TKR, with no heterogeneity (I(2) 0%).More total bleeding events were observed in the DTI group (in ximelagatran and dabigatran but not in desirudin) in patients subjected to THR (OR 1.40; 95% CI 1.06, 1.85; I(2) 41%) compared with LMWH. No difference was observed with warfarin in TKR (OR 1.76; 95% CI 0.91 to 3.38; I(2) 0%). All-cause mortality was higher in the DTI group when the reported follow-up events were included (OR 2.06; 95% CI 1.10 to 3.87).Studies that initiated anticoagulation before surgery showed less VTE events; those that began anticoagulation after surgery showed more VTE events in comparison with LMWH. Therefore, the effect of the DTIs compared with LMWH appears to be influenced by the time of initiation of coagulation more than the effect of the drug itself.The results obtained from sensitivity analysis, did not differ from the analysed results; this strengthens the value of the results.

AUTHORS' CONCLUSIONS

Direct thrombin inhibitors are as effective in the prevention of major venous thromboembolism in THR or TKR as LMWH and vitamin K antagonists. However, they show higher mortality and cause more bleeding than LMWH. No severe hepatic complications were reported in the analysed studies. Use of ximelagatran is not recommended for VTE prevention in patients who have undergone orthopedic surgery. More studies are necessary regarding dabigatran.

Resistance to benzimidazole anthelmintics in small strongyles (Cyathostominae) of horses in Denmark

This study was undertaken to establish whether anthelmintic resistance was present in nematode parasites of horses in Denmark. Sixteen horse farms were selected for faecal egg count reduction (FECR) tests to measure the efficacy of the anthelmintic used. Resistance to benzimidazole anthelmintics was found on 13 of the 16 farms, with FECR values ranging from 80.0% to -101.3%. On the remaining 3 farms FECR was 100.0%, 99.3% and 97.2%. Results of a questionnaire study on anthelmintic usage, parasite control measures and management practices showed that horses in this study were treated on average 7.1 times/year. Horse owners changed between preparations of drugs but almost only within the same class of anthelmintics. Nine owners gave an anthelmintic treatment to purchased horses before they were introduced on the farm. On 14 farms, the same paddock was grazed every year and the average stocking rate was estimated to be 2.4 horses/ha. Strategies to avoid development of anthelmintic resistance are discussed and recommendations of parasite control on horse farms are presented.