The Experts below are selected from a list of 318 Experts worldwide ranked by ideXlab platform
Lenka Skalova - One of the best experts on this subject based on the ideXlab platform.
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Flubendazole and mebendazole impair migration and epithelial to mesenchymal transition in oral cell lines
Chemico-Biological Interactions, 2018Co-Authors: Vera Kralova, Lenka Skalova, Veronika Hanusova, Kateřina Caltova, Petr Spacek, Martina Hochmalova, Emil RudolfAbstract:Benzimidazole anthelmintics Flubendazole and mebendazole are microtubule-targeting drugs that showed considerable anti-cancer activity in different preclinical models. In this study, the effects of Flubendazole and mebendazole on proliferation, migration and cadherin switching were studied in a panel of oral cell lines in vitro. Both compounds reduced the viability of the PE/CA-PJ15 and H376 oral squamous carcinoma cells and of the premalignant oral keratinocytes DOK with the IC50 values in the range of 0.19-0.26 μM. Normal oral keratinocytes and normal gingival fibroblasts were less sensitive to the treatment. Flubendazole and mebendazole also reduced the migration of the PE/CA-PJ15 cell in concentrations that had no anti-migratory effects on the normal gingival fibroblasts. Levels of the focal adhesion kinase FAK, Rho-A and Rac1 GTPases and the Rho guanine nucleotide exchange factor GEF-H1 were decreased in both PE/CA-PJ15 cells and gingival fibroblasts following treatment. Both drugs also interfered with cadherin switching in the model of TGF-β-induced epithelial to mesenchymal transition (EMT) in the DOK cell line. Levels of N-cadherin were reduced in the TGF-β induced cells co-treated with flubendazol and mebendazole in very low concentration (50 nM). These results suggest direct effects of both benzimidazoles on selected processes of EMT in oral cell lines such as cadherin switching as well as cellular migration.
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the metabolism of Flubendazole in human liver and cancer cell lines
Drug Testing and Analysis, 2018Co-Authors: Lucie Raisova Stuchlikova, Veronika Hanusova, Věra Kralova, Kateřina Lněnickova, Tomas Zarybnický, Petra Matouskova, Martin Ambrož, Z Subrt, Lenka SkalovaAbstract:Flubendazole (FLU), a benzimidazole anthelmintic drug widely used in veterinary medicine, has been approved for the treatment of gut-residing nematodes in humans. In addition, FLU is now considered a promising anti-cancer agent. Despite this, information about biotransformation of this compound in human is lacking. Moreover, there is no information regarding whether cancer cells are able to metabolize FLU in order to deactivate it. For these reasons, the present study was designed to identify all metabolites of Phase I and Phase II of FLU in human liver and in various cancer cells using ultra high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) analysis. Precision-cut human liver slices and 9 cell lines of different origin (breast, colon, oral cavity) were used as in vitro model systems. Our study showed that FLU with a reduced carbonyl group (FLUR) is the only FLU metabolite formed in the human liver. All human cancer cell lines were able to form FLUR. In addition, methylated FLUR was detected in breast cells MCF7 and intestinal SW480 cells. The accumulation of FLU and its reduction to FLUR markedly differed among cells. The extent of FLU reduction was in a good correlation with the detected expression level of carbonyl reductase 1. In most cases, FLU entered in a higher amount and was reduced to a lesser extent in proliferating (metastatic) cells than in differentiated (non-cancerous, non-metastatic) ones. These results support the promising potential of FLU in anti-cancer therapy.
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Flubendazole induces mitotic catastrophe and senescence in colon cancer cells in vitro
Journal of Pharmacy and Pharmacology, 2016Co-Authors: Věra Kralova, Emil Rudolf, Veronika Hanusova, Kristýna Caňova, Lenka SkalovaAbstract:Objectives Flubendazole (FLU), a member of benzimidazole family of anthelmintic drugs, is able to inhibit proliferation of various cancer cells. The aim of present study was to elucidate the mechanisms of antiproliferative effect of FLU on colorectal cancer cells in vitro. Methods The effect of FLU on proliferation, microtubular network, DNA content, caspase activation and senescence induction was studied in SW480 and SW620 cell lines. Key findings Flubendazole significantly affected cell proliferation in a pattern typical for mitotic inhibitor. This was accompanied by decrease in cyclin D1 levels, increase in cyclin B1 levels, activation of caspase 2 and caspase 3/7 and PARP cleavage. Morphological observations revealed disruption of microtubular network, irregular mitotic spindles, formation of giant multinucleated cells and increase in nuclear area and DNA content. In SW620 cell line, 37.5% giant multinucleated cells induced by FLU treatment showed positivity for SA-β-galactosidase staining. Cell lines were able to recover from the treatment and this process was faster in SW480 cells. Conclusion Flubendazole in low concentration temporarily inhibits cell proliferation and induces mitotic catastrophe and premature senescence in human colon cancer cells in vitro.
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the activity of drug metabolizing enzymes and the biotransformation of selected anthelmintics in the model tapeworm hymenolepis diminuta
Parasitology, 2012Co-Authors: Hana Bartikova, Jiri Lamka, Lenka Skalova, Vladimir Kubicek, Ivan Vokřal, Jana Firbasova, David Briestenský, Barbora SzotakovaAbstract:The drug-metabolizing enzymes of some helminths can deactivate anthelmintics and therefore partially protect helminths against these drugs' toxic effect. The aim of our study was to assess the activity of the main drug-metabolizing enzymes and evaluate the metabolism of selected anthelmintics (albendazole, Flubendazole, mebendazole) in the rat tapeworm Hymenolepis diminuta , a species often used as a model tapeworm. In vitro and ex vivo experiments were performed. Metabolites of the anthelmintics were detected and identified by HPLC with spectrofluorometric or mass–spectrometric detection. The enzymes of H. diminut a are able to reduce the carbonyl group of Flubendazole, mebendazole and several other xenobiotics. Although the activity of a number of oxidation enzymes was determined, no oxidative metabolites of albendazole were detected. Regarding conjugation enzymes, a high activity of glutathione S-transferase was observed. A methyl derivative of reduced Flubendazole was the only conjugation metabolite identified in ex vivo incubations of H. diminuta with anthelmintics. The results revealed that H. diminuta metabolized Flubendazole and mebendazole, but not albendazole. The biotransformation pathways found in H. diminuta differ from those described in Moniezia expanza and suggest the interspecies differences in drug metabolism not only among classes of helminths, but even among tapeworms.
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The effects of Flubendazole and its metabolites on the larval development of Haemonchus contortus (Nematoda: Trichostrongylidae): an in vitro study
Helminthologia, 2010Co-Authors: Hana Bartikova, Jiri Lamka, Lenka Skalova, Barbora Szotakova, M. VáradyAbstract:The anthelmintic effects of Flubendazole (FLU), its two main metabolites reduced Flubendazole (FLU-R) and hydrolyzed Flubendazole (FLU-H), and thiabendazole (TBZ) were compared using an in vitro larval development test in two isolates of Haemonchus contortus , a fully susceptible isolate (HCS) and a multi-resistant isolate (HCR). Results were quantified as 50 % lethal concentration (LC_50), 99 % lethal concentration (LC_99), efficacy factor (EF), and resistance factor (RF). For HCS, both LC_50 and LC_99 of FLU were lower than those of the reference TBZ. The anthelmintic activity of FLU-R in HCS and HCR was 13 and 6 times lower than the activity of FLU, respectively. The anthelmintic activity of FLU-H was negligible (approximately 363–853 times lower) compared to that of FLU. Although a marked resistance of the HCR isolate to TBZ was confirmed, only a low tolerance to FLU-R and slightly higher tolerance to FLU were found.
Barbora Szotakova - One of the best experts on this subject based on the ideXlab platform.
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the activity of drug metabolizing enzymes and the biotransformation of selected anthelmintics in the model tapeworm hymenolepis diminuta
Parasitology, 2012Co-Authors: Hana Bartikova, Jiri Lamka, Lenka Skalova, Vladimir Kubicek, Ivan Vokřal, Jana Firbasova, David Briestenský, Barbora SzotakovaAbstract:The drug-metabolizing enzymes of some helminths can deactivate anthelmintics and therefore partially protect helminths against these drugs' toxic effect. The aim of our study was to assess the activity of the main drug-metabolizing enzymes and evaluate the metabolism of selected anthelmintics (albendazole, Flubendazole, mebendazole) in the rat tapeworm Hymenolepis diminuta , a species often used as a model tapeworm. In vitro and ex vivo experiments were performed. Metabolites of the anthelmintics were detected and identified by HPLC with spectrofluorometric or mass–spectrometric detection. The enzymes of H. diminut a are able to reduce the carbonyl group of Flubendazole, mebendazole and several other xenobiotics. Although the activity of a number of oxidation enzymes was determined, no oxidative metabolites of albendazole were detected. Regarding conjugation enzymes, a high activity of glutathione S-transferase was observed. A methyl derivative of reduced Flubendazole was the only conjugation metabolite identified in ex vivo incubations of H. diminuta with anthelmintics. The results revealed that H. diminuta metabolized Flubendazole and mebendazole, but not albendazole. The biotransformation pathways found in H. diminuta differ from those described in Moniezia expanza and suggest the interspecies differences in drug metabolism not only among classes of helminths, but even among tapeworms.
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The effects of Flubendazole and its metabolites on the larval development of Haemonchus contortus (Nematoda: Trichostrongylidae): an in vitro study
Helminthologia, 2010Co-Authors: Hana Bartikova, Jiri Lamka, Lenka Skalova, Barbora Szotakova, M. VáradyAbstract:The anthelmintic effects of Flubendazole (FLU), its two main metabolites reduced Flubendazole (FLU-R) and hydrolyzed Flubendazole (FLU-H), and thiabendazole (TBZ) were compared using an in vitro larval development test in two isolates of Haemonchus contortus , a fully susceptible isolate (HCS) and a multi-resistant isolate (HCR). Results were quantified as 50 % lethal concentration (LC_50), 99 % lethal concentration (LC_99), efficacy factor (EF), and resistance factor (RF). For HCS, both LC_50 and LC_99 of FLU were lower than those of the reference TBZ. The anthelmintic activity of FLU-R in HCS and HCR was 13 and 6 times lower than the activity of FLU, respectively. The anthelmintic activity of FLU-H was negligible (approximately 363–853 times lower) compared to that of FLU. Although a marked resistance of the HCR isolate to TBZ was confirmed, only a low tolerance to FLU-R and slightly higher tolerance to FLU were found.
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effect of Flubendazole on biotransformation enzymes activities inhaemonchus contortus
The Open Parasitology Journal, 2010Co-Authors: Ivan Vokřal Beatriz Vermelho, Jiri Lamka, Barbora Szotakova, Milan Nobilis, V Křižova, Vladimir Kubicek, Marian Varady, Claudia M Davilalevy, Lenka SkalovaAbstract:The aim of present project was to find out if in vivo contact of Haemonchus contortus with benzimidazole an- thelmintic Flubendazole (FLU) during treatment of its hosts (sheep) with low doses of FLU affects helminths' drug- metabolizing enzyme activities. Four groups of lambs, experimentally infected with H. contortus, were treated three-times orally with 0.0, 0.25, 0.50 or 1.00 mg per kg of body weight of FLU in three consecutive days. Twenty four hours after the last FLU dose, the nematodes were isolated, homogenized and subcellular fractions were prepared. In these subcellular fractions, biotransformation of FLU and the activities of carbonyl reducing enzymes and conjugation enzymes were as- sayed. The results showed that H. contortus enzymes were able to conjugate p-nitrophenol with glucose but not with glu- curonic acid. The exposure of H.contortus to FLU (the highest FLU dose) caused a significant increase in activities of FLU reductases, D,L-glyceraldehyde reductases and glutathion S-transferases.
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Activities of biotransformation enzymes and Flubendazole metabolism in lambs (Ovis aries): effect of gender and Flubendazole therapy
Pharmacological Reports, 2010Co-Authors: Hana Bartikova, Lenka Skalova, Jiří Lamka, Vladimir Kubicek, Veronika Křížová, Martina Štěpničková, Barbora SzotakovaAbstract:The effect of Flubendazole (FLU) therapy on in vitro FLU biotransformation and the activities of selected biotransformation enzymes were investigated in male and female lambs. Four experimental groups were used: control (untreated) ewes and rams and FLU-treated ewes and rams (orally, 15 mg/kg per day, for three consecutive days). Subcellular fractions were prepared from liver and intestinal mucosa 24 h after the final dosage was administered. Activities of cytochromes P450 (CYP), flavine monooxygenases (FMO), carbonyl reducing enzymes, UDP-glucuronosyl transferase (UGT) and glutathione S-transferase were tested. Significant gender differences were observed for FMO-mediated activity (2-fold higher in ram lambs) and UGT activity (up to 30% higher in ewe lambs), but no gender differences were observed in FLU metabolism. FLU-treatment of lambs moderately changed the activities of some CYPs, FMO, and UGT in liver microsomes. In vitro FLU reduction was not altered in the liver, but was slightly higher in the small intestine of FLU pre-treated lambs. This correlated with the higher carbonyl reductase activities measured in the gut mucosa of these animals.
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Flubendazole metabolism and biotransformation enzymes activities in healthy sheep and sheep with haemonchosis
Journal of Veterinary Pharmacology and Therapeutics, 2010Co-Authors: Hana Bartikova, Jiri Lamka, Lenka Skalova, V Křižova, Vladimir Kubicek, Barbora SzotakovaAbstract:Bartikova, H., Křižova, V., Lamka, J., Kubicek, V., Skalova, L., Szotakova, B. Flubendazole metabolism and biotransformation enzymes activities in healthy sheep and sheep with haemonchosis. J. vet. Pharmacol. Therap. 33, 56–62. The aim of this project was to study the influence of haemonchosis, a common parasitic infection of small ruminants caused by Haemonchus contortus, on the activity of biotransformation enzymes and on in vitro Flubendazole (FLU) biotransformation in liver and small intestine of lambs (Ovis aries). Twelve lambs were divided into three groups: non-infected animals, animals orally infected with larvae of H. contortus ISE strain for 7 weeks and for 11 weeks. At the end of the experiment, hepatic and intestinal subcellular fractions were prepared and used for assays of biotransformation enzymes activities and FLU metabolism testing. The activities of hepatic cytochromes P450, flavine monooxygenases and carbonyl-reducing enzymes were decreased in infected animals. UDP-glucuronosyl transferase activity was significantly lower (by 35%) in 11 weeks infected animals than that in control animals. When in vitro metabolism of FLU was compared in control and infected animals, significantly lower velocity of FLU reduction was found in infected animals. Slower FLU reduction may be beneficial for the haemonchosis treatment using FLU, because FLU will remain longer in the organism and could cause longer contact of parasites with FLU.
Jiri Lamka - One of the best experts on this subject based on the ideXlab platform.
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the activity of drug metabolizing enzymes and the biotransformation of selected anthelmintics in the model tapeworm hymenolepis diminuta
Parasitology, 2012Co-Authors: Hana Bartikova, Jiri Lamka, Lenka Skalova, Vladimir Kubicek, Ivan Vokřal, Jana Firbasova, David Briestenský, Barbora SzotakovaAbstract:The drug-metabolizing enzymes of some helminths can deactivate anthelmintics and therefore partially protect helminths against these drugs' toxic effect. The aim of our study was to assess the activity of the main drug-metabolizing enzymes and evaluate the metabolism of selected anthelmintics (albendazole, Flubendazole, mebendazole) in the rat tapeworm Hymenolepis diminuta , a species often used as a model tapeworm. In vitro and ex vivo experiments were performed. Metabolites of the anthelmintics were detected and identified by HPLC with spectrofluorometric or mass–spectrometric detection. The enzymes of H. diminut a are able to reduce the carbonyl group of Flubendazole, mebendazole and several other xenobiotics. Although the activity of a number of oxidation enzymes was determined, no oxidative metabolites of albendazole were detected. Regarding conjugation enzymes, a high activity of glutathione S-transferase was observed. A methyl derivative of reduced Flubendazole was the only conjugation metabolite identified in ex vivo incubations of H. diminuta with anthelmintics. The results revealed that H. diminuta metabolized Flubendazole and mebendazole, but not albendazole. The biotransformation pathways found in H. diminuta differ from those described in Moniezia expanza and suggest the interspecies differences in drug metabolism not only among classes of helminths, but even among tapeworms.
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The effects of Flubendazole and its metabolites on the larval development of Haemonchus contortus (Nematoda: Trichostrongylidae): an in vitro study
Helminthologia, 2010Co-Authors: Hana Bartikova, Jiri Lamka, Lenka Skalova, Barbora Szotakova, M. VáradyAbstract:The anthelmintic effects of Flubendazole (FLU), its two main metabolites reduced Flubendazole (FLU-R) and hydrolyzed Flubendazole (FLU-H), and thiabendazole (TBZ) were compared using an in vitro larval development test in two isolates of Haemonchus contortus , a fully susceptible isolate (HCS) and a multi-resistant isolate (HCR). Results were quantified as 50 % lethal concentration (LC_50), 99 % lethal concentration (LC_99), efficacy factor (EF), and resistance factor (RF). For HCS, both LC_50 and LC_99 of FLU were lower than those of the reference TBZ. The anthelmintic activity of FLU-R in HCS and HCR was 13 and 6 times lower than the activity of FLU, respectively. The anthelmintic activity of FLU-H was negligible (approximately 363–853 times lower) compared to that of FLU. Although a marked resistance of the HCR isolate to TBZ was confirmed, only a low tolerance to FLU-R and slightly higher tolerance to FLU were found.
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effect of Flubendazole on biotransformation enzymes activities inhaemonchus contortus
The Open Parasitology Journal, 2010Co-Authors: Ivan Vokřal Beatriz Vermelho, Jiri Lamka, Barbora Szotakova, Milan Nobilis, V Křižova, Vladimir Kubicek, Marian Varady, Claudia M Davilalevy, Lenka SkalovaAbstract:The aim of present project was to find out if in vivo contact of Haemonchus contortus with benzimidazole an- thelmintic Flubendazole (FLU) during treatment of its hosts (sheep) with low doses of FLU affects helminths' drug- metabolizing enzyme activities. Four groups of lambs, experimentally infected with H. contortus, were treated three-times orally with 0.0, 0.25, 0.50 or 1.00 mg per kg of body weight of FLU in three consecutive days. Twenty four hours after the last FLU dose, the nematodes were isolated, homogenized and subcellular fractions were prepared. In these subcellular fractions, biotransformation of FLU and the activities of carbonyl reducing enzymes and conjugation enzymes were as- sayed. The results showed that H. contortus enzymes were able to conjugate p-nitrophenol with glucose but not with glu- curonic acid. The exposure of H.contortus to FLU (the highest FLU dose) caused a significant increase in activities of FLU reductases, D,L-glyceraldehyde reductases and glutathion S-transferases.
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Flubendazole metabolism and biotransformation enzymes activities in healthy sheep and sheep with haemonchosis
Journal of Veterinary Pharmacology and Therapeutics, 2010Co-Authors: Hana Bartikova, Jiri Lamka, Lenka Skalova, V Křižova, Vladimir Kubicek, Barbora SzotakovaAbstract:Bartikova, H., Křižova, V., Lamka, J., Kubicek, V., Skalova, L., Szotakova, B. Flubendazole metabolism and biotransformation enzymes activities in healthy sheep and sheep with haemonchosis. J. vet. Pharmacol. Therap. 33, 56–62. The aim of this project was to study the influence of haemonchosis, a common parasitic infection of small ruminants caused by Haemonchus contortus, on the activity of biotransformation enzymes and on in vitro Flubendazole (FLU) biotransformation in liver and small intestine of lambs (Ovis aries). Twelve lambs were divided into three groups: non-infected animals, animals orally infected with larvae of H. contortus ISE strain for 7 weeks and for 11 weeks. At the end of the experiment, hepatic and intestinal subcellular fractions were prepared and used for assays of biotransformation enzymes activities and FLU metabolism testing. The activities of hepatic cytochromes P450, flavine monooxygenases and carbonyl-reducing enzymes were decreased in infected animals. UDP-glucuronosyl transferase activity was significantly lower (by 35%) in 11 weeks infected animals than that in control animals. When in vitro metabolism of FLU was compared in control and infected animals, significantly lower velocity of FLU reduction was found in infected animals. Slower FLU reduction may be beneficial for the haemonchosis treatment using FLU, because FLU will remain longer in the organism and could cause longer contact of parasites with FLU.
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liquid chromatography mass spectrometric identification of benzimidazole anthelminthics metabolites formed ex vivo by dicrocoelium dendriticum
Rapid Communications in Mass Spectrometry, 2009Co-Authors: V Cvilink, Hana Bartikova, Ivan Vokral, Jiri Lamka, Barbora Szotakova, Lenka SkalovaAbstract:With further use of chemical agents in the control of parasitic infections, an increased number of drug resistance occurrences to antiparasitic drugs has been reported. Induction of enzymes responsible for detoxification of given drugs can contribute to drug resistance development in a parasitic organism. The identification of formed metabolites allows the characterization of the enzymes participating in biotransformation and possibly in drug resistance development. The objective of our work was to find and identify phase I and phase II metabolites of the anthelminthic drugs albendazole, Flubendazole and mebendazole formed in ex vivo incubations by the parasitic helminth Dicrocoelium dendriticum, a parasite of ruminants and other grazing animals, using liquid chromatography/mass spectrometric (LC/MS) techniques. In the ex vivo study, approximately 50 living D. dendriticum adults were incubated in 5 mL RPMI-1640 medium in the presence of 10.0 µmol L−1 benzimidazole drug (5% CO2, 38°C) for 24 h. The bodies of the parasite were then removed from the medium. After homogenization of parasites, both parasite homogenates and medium from the incubation were separately extracted using solid-phase extraction. The extracts were analyzed using LC/MS with electrospray ionization. The results showed that D. dendriticum enzymatic systems are capable of phase I oxidation and reduction as well as phase II conjugation reactions. Detected phase I metabolites comprised albendazole sulfoxide, reduced Flubendazole and reduced mebendazole. As for phase II metabolites, methyl derivatives of both reduced Flubendazole and reduced mebendazole were observed. Copyright © 2009 John Wiley & Sons, Ltd.
Milan Nobilis - One of the best experts on this subject based on the ideXlab platform.
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effect of Flubendazole on biotransformation enzymes activities inhaemonchus contortus
The Open Parasitology Journal, 2010Co-Authors: Ivan Vokřal Beatriz Vermelho, Jiri Lamka, Barbora Szotakova, Milan Nobilis, V Křižova, Vladimir Kubicek, Marian Varady, Claudia M Davilalevy, Lenka SkalovaAbstract:The aim of present project was to find out if in vivo contact of Haemonchus contortus with benzimidazole an- thelmintic Flubendazole (FLU) during treatment of its hosts (sheep) with low doses of FLU affects helminths' drug- metabolizing enzyme activities. Four groups of lambs, experimentally infected with H. contortus, were treated three-times orally with 0.0, 0.25, 0.50 or 1.00 mg per kg of body weight of FLU in three consecutive days. Twenty four hours after the last FLU dose, the nematodes were isolated, homogenized and subcellular fractions were prepared. In these subcellular fractions, biotransformation of FLU and the activities of carbonyl reducing enzymes and conjugation enzymes were as- sayed. The results showed that H. contortus enzymes were able to conjugate p-nitrophenol with glucose but not with glu- curonic acid. The exposure of H.contortus to FLU (the highest FLU dose) caused a significant increase in activities of FLU reductases, D,L-glyceraldehyde reductases and glutathion S-transferases.
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sensitive chiral high performance liquid chromatographic determination of anthelmintic Flubendazole and its phase i metabolites in blood plasma using uv photodiode array and fluorescence detection application to pharmacokinetic studies in sheep
Journal of Chromatography B, 2008Co-Authors: Jiri Lamka, Barbora Szotakova, Milan Nobilis, Z Vybiralova, V Křižova, Vladimir Kubicek, Marie Soukupova, Lenka SkalovaAbstract:Abstract Although benzimidazole anthelmintic Flubendazole, methyl ester of [5-(4-fluorobenzoyl)-1H-benzimidazol-2-yl]carbamic acid, is extensively used in veterinary and human medicine for the treatment of gastrointestinal parasitic helmint infections, reliable data about its pharmacokinetics in various species have not been reported. Our previous work [M. Nobilis, Th. Jira, M. Lisa, M. Holcapek, B. Szotakova, J. Lamka, L.Skalova, J. Chromatogr. A 1149 (2007) 112–120] had described the stereospecificity of carbonyl reduction during phase I metabolic experiments in vitro. For in vivo pharmacokinetic studies, further improvement and optimization of bioanalytical HPLC method in terms of sensitivity and selectivity was necessary. Hence, a modified chiral bioanalytical HPLC method involving both UV photodiode-array and fluorescence detection for the determination of Flubendazole, both enantiomers of reduced Flubendazole and hydrolyzed Flubendazole in the extracts from plasma samples was tested and validated. Albendazole was used as an internal standard. Sample preparation process involved a pH-dependent extraction of the analytes from the blood plasma into tert-butylmethyl ether. Chromatographic separations were performed on a Chiralcel OD-R 250 mm × 4.6 mm column with mobile phase methanol-1 M NaClO4 (75:25, v/v) at the flow rate 0.5 ml min−1. In quantitation, selective UV absorption maxima of 290 nm (for reduced Flubendazole), 295 nm (for albendazole), 310 nm (for Flubendazole) and 330 nm (for hydrolyzed Flubendazole) were used in the UV photodiode-array detection, and λ(exc.)/λ(emis.) = 228 nm/310 nm (for reduced Flubendazole) and λ(exc.)/λ(emis.) = 236 nm/346 nm (for albendazole) were set on the fluorescence detector. The fluorescence detection was approximately 10-times more sensitive than the UV detection. Each HPLC run lasted 27 min. The validated chiral HPLC-PDA-FL method was employed in the pharmacokinetic studies of Flubendazole in sheep. The stereospecificity of the enzymatic carbonyl reduction of Flubendazole was also observed in vivo. (+)-Reduced Flubendazole was found to be the principal metabolite in ovine blood plasma and only low concentrations of hydrolyzed Flubendazole, the parent Flubendazole and (−)-reduced Flubendazole were detected in this biomatrix.
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lc with fluorimetric detection for sensitive analysis of reduced Flubendazole in biological samples
Chromatographia, 2008Co-Authors: Vladimir Kubicek, Barbora Szotakova, Milan Nobilis, V Křižova, Marie Soukupova, Lenka SkalovaAbstract:A validated LC method is proposed for analysis of Flubendazole and its metabolites in biological samples of Haemonchus contortus. Two detectors were used—photodiode-array and spectrofluorimetric. The native fluorescence of reduced Flubendazole, the key substance investigated during biological experiments, was used for its fluorimetric detection with a very low limit of quantification (0.63 nmol L−1).
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biotransformation of Flubendazole and selected model xenobiotics in haemonchus contortus
Veterinary Parasitology, 2008Co-Authors: V Cvilink, Jiri Lamka, Barbora Szotakova, Milan Nobilis, V Křižova, Vladimir Kubicek, Marian Varady, M Kuběnova, Romana Novotna, Martina GavelovaAbstract:Abstract Haemonchus contortus is one of the most pathogenic parasites of small ruminants (e.g., sheep and goat). The treatment of haemonchosis is complicated because of frequent resistance of H. contortus to common anthelmintics. The development of resistance can be facilitated by the action of drug metabolizing enzymes of parasites that can deactivate anthelmintics and thus protect parasites against the toxic effect of the drug. The aim of this project was to investigate the Phase I biotransformation of benzimidazole anthelmintic Flubendazole in H. contortus and to determine the biotransformation of other model xenobiotics. For this purpose, in vitro (subcellular fractions of H. contortus homogenate) as well as ex vivo (live nematodes cultivated in flasks with medium) experiments were used. The results showed that cytosolic NADPH-dependent enzymes of H. contortus metabolize Flubendazole via reduction of its carbonyl group. The apparent kinetic parameters of this reaction were determined ( V ′ max = 39.8 ± 2.1 nM mi n − 1 , K ′ m = 1.5 ± 0.3 μ M ). The reduction of Flubendazole in H. contortus is stereospecific, the ratio of (−):(+) enantiomers of reduced Flubendazole formed was 90:10. Reduced Flubendazole was the only Phase I metabolite found. Effective reduction of other xenobiotics with carbonyl group (metyrapon, daunorubicin, and oracin) was also found. Significant activity of carbonyl-reducing enzymes may be important for H. contortus to survive the attacks of anthelmintics or other xenobiotics with carbonyl group.
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achiral and chiral high performance liquid chromatographic determination of Flubendazole and its metabolites in biomatrices using uv photodiode array and mass spectrometric detection
Journal of Chromatography A, 2007Co-Authors: Milan Nobilis, Jiri Lamka, Barbora Szotakova, Thomas Jira, Miroslav Lisa, Michal Holcapek, Lenka SkalovaAbstract:Flubendazole, methyl ester of [5-(4-fluorobenzoyl)-1H-benzimidazol-2-yl]carbamic acid, belongs to the group of benzimidazole anthelmintics, which are widely used in veterinary and human medicine. The phase I Flubendazole biotransformation includes a hydrolysis of the carbamoyl methyl moiety accompanied by a decarboxylation (hydrolysed Flubendazole) and a carbonyl reduction of Flubendazole (reduced Flubendazole). Flubendazole is a prochiral drug, hence a racemic mixture is formed during non-stereoselective reductions at the carbonyl group. Two bioanalytical HPLC methods were developed and validated for the determination of Flubendazole and its metabolites in pig and pheasant hepatic microsomal and cytosolic fractions. Analytes were extracted from biomatrices into tert-butylmethyl ether. The first, achiral method employed a 250 mm × 4 mm column with octylsilyl silica gel (5m) and an isocratic mobile phase acetonitrile–0.025 M KH2PO4 buffer pH 3 (28:72, v/v). Albendazole was used as an internal standard. The whole analysis lasted 27 min at a flow rate of 1 ml/min. The second, chiral HPLC method, was performed on a Chiralcel OD-R 250 mm × 4.6 mm column with a mobile phase acetonitrile–1 M NaClO4 (4:6, v/v). This method enabled the separation of both reduced Flubendazole enantiomers. The enantiomer excess was evaluated. The column effluent was monitored using a photodiode-array detector (scan or single wavelength at λ = 246 nm). Each of the analytes under study had characteristic UV spectrum, in addition, their chemical structures were confirmed by high-performance liquid chromatography–mass spectrometry (HPLC–MS) experiments. Stereospecificity in the enzymatic carbonyl reduction of Flubendazole was observed. While synthetic racemic mixture of reduced Flubendazole was separated to equimolar amounts of both enantiomers, practically only one enantiomer was detected in the extracts from all incubates.
Hongkun Zhao - One of the best experts on this subject based on the ideXlab platform.
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solubility and preferential solvation of Flubendazole dissolved in aqueous co solvent mixtures of 1 4 dioxane dimethyl sulfoxide n n dimethylformamide and isopropanol
The Journal of Chemical Thermodynamics, 2019Co-Authors: Min Zheng, Jingchao Han, Jinhua Liang, Hongkun ZhaoAbstract:Abstract The equilibrium solubility of Flubendazole in four co-solvent mixtures of dimethyl sulfoxide (DMSO,1) + water (2), N,N-dimethylformamide (DMF,1) + water (2), isopropanol (1) + water (2) and 1,4-dioxane (1) + water (2) at temperature range from (283.15 to 333.15) K was reported. At the same composition of DMSO, DMF, isopropanol or 1,4-dioxane and temperature, the mole fraction solubility of Flubendazole was highest in DMSO (1) + water (2) mixtures, and lowest in isopropanol (1) + water (2) mixtures. By using the Jouyban-Acree model, van’t Hoff-Jouyban-Acree model and Apelblat-Jouyban-Acree model, Flubendazole solubility was well correlated obtaining RAD lower than 5.08% and RMSD lower than 0.20 × 10−4. Quantitative values for the local mole fraction of DMSO (DMF, isopropanol or 1,4-dioxane) and water around the Flubendazole were computed by using the Inverse Kirkwood–Buff integrals method applied to the determined solubility data. Flubendazole was preferentially solvated by water in water-rich compositions; while in intermediate and co-solvent-rich composition for DMF (DMSO, 1,4-dioxane) (1) + water (2) mixtures, Flubendazole is preferentially solvated by the co-solvent. While for the isopropanol (1) + water (2) mixture, Flubendazole was preferentially solvated by water in water-rich and co-solvent-rich compositions; and preferentially solvated by isopropanol in intermediate compositions. The preferential solvation magnitude of Flubendazole was highest in 1,4-dioxane mixtures than in the other three co-solvent mixtures.
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solubility modeling and solvent effect for Flubendazole in 12 neat solvents
Journal of Chemical & Engineering Data, 2019Co-Authors: Jinhua Liang, Min Zheng, Jingchao Han, Hongkun ZhaoAbstract:The method of shake-flask was used in studying the solubility of Flubendazole in water, n-propanol, ethanol, isopropyl alcohol, methanol, isobutyl alcohol, n-butanol, N,N-dimethylformamide, 1,4-dioxane, 2-butanone, dimethyl sulfoxide (DMSO), and N-methyl-2-pyrrolidone. The determination was made over the temperatures from 283.15 K to 333.15 K under ambient pressure p = 101.2 kPa. The values of Flubendazole solubility in mole fraction in these solvents increased with rising temperature. They were highest in DMSO and lowest in water. The gained solubility was mathematically described through the Apelblat equation. The maximum average relative deviation and root-mean-square deviation were 2.69% and 3.60 × 10–5, respectively. In addition, using the relationship analysis of linear solvation energy of solvent effect, the degree and type of solvent–solvent and solute–solvent interactions were identified.