RESUMO
Metastable and rarely reported GO warped tetragonal phase t-lanthanum vanadate nanocomposites (GO@LaVO4-NCs) are reported for the sensitive electrochemical determination of antifungal drug Clioquinol (CQ). The hydrothermal method was adopted for synthesis of GO@LaVO4-NCs. The electrochemical performance of CQ was examined using cyclic voltammetry (CV) and differential plus voltammetry (DPV) at GO@LaVO4-NCs modified glassy carbon electrode (GCE). The electrocatalytic oxidation of CQ at the GO@LaVO4-NCs/GCE shows the highest anodic peak current at a potential of +0.51 V vs. Ag/AgCl. The proposed sensor provides excellent sensitivity of 4.1894 µA µM-1 cm-2, a very low detection limit (LOD) of 2.44 nM, and a wide range of 25 nM to 438.52 µM towards CQ detection. Finally, the detection of CQ in biological media was successfully done using the GO@LaVO4-NCs/GCE and possesses recoveries of 94.67-98.0%.
Assuntos
Antifúngicos/análise , Antiprotozoários/análise , Clioquinol/análise , Técnicas Eletroquímicas/métodos , Nanocompostos/química , Antifúngicos/sangue , Antifúngicos/química , Antifúngicos/urina , Antiprotozoários/sangue , Antiprotozoários/química , Antiprotozoários/urina , Clioquinol/sangue , Clioquinol/química , Clioquinol/urina , Grafite/química , Humanos , Lantânio/química , Limite de Detecção , Oxirredução , Reprodutibilidade dos Testes , Vanadatos/químicaRESUMO
We developed and validated an ultra-performance liquid chromatographic (UPLC) method coupled with atmospheric pressure chemical ionization (APCI) mass spectrometry for simultaneous determination of levornidazole and its first-pass metabolites, l-chloro-3-(2-hydroxymethyl-5-nitro-l-imidazolyl)-2-propanol (Ml), 2-methyl-5-nitroimidazole (M2) and 3-(2-methyl-5-nitro-1-imidazolyl)-1,2-propanediol (M4), in human plasma and urine. The biological samples were pretreated by protein precipitation and liquid-liquid extraction and analyzed using an ACQUITY UPLC CSH C18 column (2.1×50 mm, 1.7 µm) and a QTRAP mass spectrometer in multiple reaction monitoring mode via APCI. Acetonitrile and 0.1% formic acid in water was used as the mobile phase in gradient elution at a flow rate of 0.6 mL/min. The lower limit of quantification of this method was 0.0100, 0.00500, 0.0200 and 0.00250 µg/mL for levornidazole, M1, M2 and M4, respectively. The linear calibration curves were obtained for levornidazole, M1, M2, and M4 over the range of 0.0100-5.00, 0.00500-2.50, 0.0200-10.0 and 0.00250-1.25 µg/mL, respectively. The intra- and inter-batch precision was less than 12.2% in plasma and less than 10.8% in urine. The intra- and inter-batch accuracy was 87.8-105.7% in plasma and 92.8-109.2% in urine. The mean recovery of levornidazole, M1, M2 and M4 was 91.1-105.1%, 95.8-103.8%, 87.8-96.8%, 96.8-100.6% from plasma and 96.0-100.9%, 96.9-107.9%, 95.1-102.7%, 103.7-105.9% from urine respectively. This method was validated under various conditions, including room temperature, freeze-thaw cycles, long-term storage at -40 ± 5°C, after pretreatment in the autosampler (at 10°C), and 10- and 100-fold dilution. This newly established analytical method was successfully applied in a pharmacokinetic study following single intravenous infusion of levornidazole in 24 healthy Chinese subjects.
Assuntos
Antiprotozoários/sangue , Antiprotozoários/urina , Cromatografia Líquida/métodos , Ornidazol/sangue , Ornidazol/urina , Espectrometria de Massas em Tandem/métodos , Antiprotozoários/química , Feminino , Humanos , Isomerismo , Limite de Detecção , Masculino , Ornidazol/análogos & derivadosRESUMO
Pentavalent antimony (Sb(V)) compounds are the drugs of choice for the treatment of all forms of leishmaniasis. For 20 years there has been an interest in antifungal azoles for treating leishmaniasis, with variable success. In the current study, we examined the effects of co-administration of fluconazole (FLZ) on the pharmacokinetics and pharmacodynamics of Sb(V) in cutaneous leishmaniasis-infected hamsters. Hamsters were divided into four groups. All hamsters were injected with 0.1 mL of 1x10(8)promastigotes/mL into the right foot on Day 1. Treatment was started 5 days after the infection. The antimony group received 80 mg/kg/day of Pentostam intramuscularly whilst the FLZ group received FLZ 20 mg/kg/day orally for 14 days. The combination group received both Pentostam and FLZ at the above mentioned doses for 14 days. Animals in the control group received no treatment. The infected footpads were measured on Days 1 and 14. A pharmacokinetic study was conducted on Days 1 and 14 of treatment, representing single- and multiple-dose pharmacokinetics, respectively. Blood samples were collected at different time intervals up to 24h. Sb(V) was determined using flameless atomic absorption spectrophotometry. Pharmacokinetic parameters were calculated using a non-compartmental analysis. In the single-dose study, there was no statistically significant difference in any of the pharmacokinetic parameters of Sb(V) when given alone or with FLZ. However, on Day 14 a significant increase in peak plasma concentration (C(max)) (three-fold) and area under the concentration-time curve (AUC) (four-fold) of antimony was observed when Sb(V) was co-administered with FLZ. A statistically significant prolongation of the terminal half-life from 1.63 to 8.67 h (P<0.05) was also observed. A significant reduction in clearance was detected. However, FLZ had no effect on the pharmacodynamics of Sb(V) as measured by footpad sizes. In conclusion, FLZ did not improve the therapeutic effect of Sb(V) when given concomitantly despite the significant increase in blood concentration and prolongation of the elimination half-life of Sb(V).
Assuntos
Antifúngicos/farmacologia , Antimônio/farmacocinética , Antiprotozoários/farmacocinética , Fluconazol/farmacologia , Leishmaniose Cutânea/metabolismo , Administração Oral , Animais , Antifúngicos/administração & dosagem , Antimônio/administração & dosagem , Antimônio/sangue , Antimônio/urina , Antiprotozoários/administração & dosagem , Antiprotozoários/sangue , Antiprotozoários/urina , Área Sob a Curva , Cricetinae , Quimioterapia Combinada , Fluconazol/administração & dosagem , Meia-Vida , Injeções Intravenosas , Mesocricetus , Distribuição AleatóriaRESUMO
OBJECTIVE: To study the renal excretion and kidney accumulation of pentamidine, a potentially nephrotoxic compound, in the isolated perfused rat kidney (IPK). MATERIALS AND METHODS: IPK experiments (3-4 per treatment group) were conducted using male Sprague-Dawley rats (250-350 g). Dose proportionality studies were carried out over a pentamidine dosing range of 80-4000 microg, designed to target initial perfusate concentrations from 1 to 50 microg/mL. Separate interaction experiments were conducted between pentamidine (800 microg) and tetraethylammonium (dose 8000 microg) or dideoxyinosine (dose 80 microg). Inulin was used as a glomerular filtration rate (GFR) marker. Control (drug-naive) perfusions were also carried out. Pentamidine was analysed in perfusate, kidney and urine samples by HPLC. Inulin was measured by a colorimetric method. RESULTS: Pentamidine CLR (1.1 +/- 0.6 to 0.05 +/- 0.03 mL/min) and excretion ratio (3.6 +/- 1.5 to 0.56 +/- 0.15) significantly decreased over the range of doses studied. Significant reductions in viability parameters (GFR, Na reabsorption) were noted in kidneys perfused with high dose pentamidine (4000 microg). Tetraethylammonium co-administration reduced pentamidine renal excretion, resulting in significantly greater kidney accumulation of pentamidine and reduced kidney function. Dideoxyinosine administration had minimal effects on pentamidine disposition. CONCLUSIONS: Pentamidine renal transport involves a combination of mechanisms (filtration, secretion and passive reabsorption). Dose proportionality studies demonstrated non-linear excretion of pentamidine. Inhibition of pentamidine renal clearance by tetraethylammonium was consistent with decreased luminal transport. The detrimental effects of pentamidine on kidney function were the result of significant kidney accumulation of drug. The potential exists for drug-drug interactions between pentamidine and organic cations, increasing the risk of drug-induced nephrotoxicity.
Assuntos
Antiprotozoários/urina , Rim/metabolismo , Pentamidina/urina , Algoritmos , Animais , Transporte Biológico Ativo , Cromatografia Líquida de Alta Pressão , Didanosina/farmacologia , Relação Dose-Resposta a Droga , Taxa de Filtração Glomerular , Técnicas In Vitro , Testes de Função Renal , Masculino , Perfusão , Ligação Proteica , Ratos , Ratos Sprague-Dawley , Compostos de Tetraetilamônio/farmacologiaRESUMO
Following the regimen used to treat equine protozoal myeloencephalitis, sulfadiazine (20 mg/kg) and pyrimethamine (1mg/kg) were administered orally once daily to 12 physically conditioned Thoroughbred horses for 4 consecutive days. The horses were randomly assigned to two test groups in a crossover design, with each horse serving as its own control. A stepwise exercise stress test was conducted to exhaustion. No effect on athletic performance was observed, and only marginal effects were noted in some hematologic and serochemical measurements, including decreased total white blood cell counts, red blood cell distribution width, total hemoglobin, serum sodium, and serum chloride. Serum folic acid concentration decreased significantly following sulfadiazine/pyrimethamine treatment.
Assuntos
Antiprotozoários/farmacologia , Cavalos/fisiologia , Condicionamento Físico Animal/fisiologia , Pirimetamina/farmacologia , Sulfadiazina/farmacologia , Animais , Antiprotozoários/sangue , Antiprotozoários/farmacocinética , Antiprotozoários/urina , Contagem de Células Sanguíneas , Glicemia , Creatinina/sangue , Creatinina/urina , Quimioterapia Combinada , Teste de Esforço/efeitos dos fármacos , Teste de Esforço/veterinária , Feminino , Ácido Fólico/sangue , Frequência Cardíaca/efeitos dos fármacos , Masculino , Consumo de Oxigênio/efeitos dos fármacos , Pirimetamina/sangue , Pirimetamina/farmacocinética , Pirimetamina/urina , Sulfadiazina/sangue , Sulfadiazina/farmacocinética , Sulfadiazina/urina , Vitamina B 12/sangueRESUMO
Cyclic voltammetry was used to explore the adsorption behavior of secnidazole on a hanging mercury drop electrode (HMDE). The effects of various operational parameters on the accumulation behavior of the adsorbed species were tested. Thus, a sensitive stripping voltammetry procedure for the determination of secnidazole with an adsorptive accumulation on the surface of HMDE has been developed. Measurements were taken by differential-pulse voltammetry after determination of the optimum conditions. The linear concentration range was 1 x 10(-8)-1 x 10(-7) s when using a 120 s preconcentration at -0.1 V vs. Ag/AgCl in acetate buffer of pH 4.0. The detection limit of secnidazole was 5 x 10(-9) M. The precision, expressed by the coefficient of variation, was 2.5% (n = 10) at a concentration of 1 x 10(-7) m. The method was successfully applied to the analysis of secnidazole in urine.
Assuntos
Antiprotozoários/urina , Metronidazol/análogos & derivados , Eletroquímica , Eletrodos , Humanos , Concentração de Íons de Hidrogênio , Indicadores e Reagentes , Mercúrio/química , Metronidazol/urina , OxirreduçãoRESUMO
Colostomized chickens given oral doses of 3,5-dinitrobenzamide (nitromide) cleared nitromide predominantly through the urine (58% of dose) and feces (21% of dose). Rats cleared 52% of nitromide via urinary excretion and 44% via feces. Major urinary metabolites for both chickens and rats include: 3-amino-5-nitrobenzamide, 3-acetamido-5-nitrobenzamide, 3-acetamide-5-aminobenzamide, and 3,5-diacetamidobenzamide. The major fecal metabolite in chickens was 3-acetamido-5-nitrobenzamide (67% of fecal 14C) and 3-acetamido-5-aminobenzamide in rats (approximately 50%).
Assuntos
Antiprotozoários/farmacocinética , Benzamidas/farmacocinética , Administração Oral , Ração Animal , Animais , Antiprotozoários/metabolismo , Antiprotozoários/urina , Benzamidas/metabolismo , Benzamidas/urina , Galinhas , Colostomia/veterinária , Fezes/química , Aditivos Alimentares , Masculino , Ratos , Ratos Sprague-DawleyRESUMO
Tandem mass spectrometry is usually employed to achieve rapid screening or structure elucidation. We have used liquid chromatography-tandem mass spectrometry in order to detect metabolites of the antiprotozoal drug pentamidine in urine. Samples of urine from rat and man were analysed both by direct injection and after solid-phase extraction. The present paper discusses advantages and disadvantages of using direct injection of urine samples, optimization of chromatographic conditions with regard to the performance of the mass spectrometer, automation and stability of the entire system.
Assuntos
Antiprotozoários/urina , Cromatografia Líquida/métodos , Espectrometria de Massas/métodos , Pentamidina/urina , Animais , Antiprotozoários/química , Antiprotozoários/metabolismo , Humanos , Pentamidina/química , Pentamidina/metabolismo , Ratos , Reprodutibilidade dos TestesRESUMO
A number of parameters influencing the electrokinetic processing of pentamidine by micellar electrokinetic chromatography (MEKC) were studied in order to develop an analytical method for this compound. The parameters considered were: pH, ionic strength, and SDS concentration of electrolyte, temperature and working voltage. On the basis of the results obtained, the best analytical conditions for the detection of pentamidine in serum and urine by MEKC were determined. Analysis by MEKC permitted determination of the drug in 10 min. Good linearity, reproducibility and accuracy were obtained in the range 0-30 micrograms/ml for both samples, with a correlation coefficient r > or = 0.9998 and a recovery of 87-92% in serum and 90-108.9% in urine. We examined the metabolism of pentamidine using rat liver homogenates in order to exclude any possible interference of metabolites in the analysis of pentamidine.
Assuntos
Antiprotozoários/análise , Cromatografia Líquida de Alta Pressão/métodos , Pentamidina/análise , Animais , Antiprotozoários/sangue , Antiprotozoários/urina , Eletroquímica , Humanos , Concentração de Íons de Hidrogênio , Modelos Lineares , Fígado/química , Masculino , Micelas , Concentração Osmolar , Pentamidina/sangue , Pentamidina/urina , Ratos , Ratos Sprague-Dawley , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Dodecilsulfato de Sódio/química , Tensoativos/química , TemperaturaRESUMO
A sensitive and selective high-performance liquid chromatographic (HPLC) method was developed for the determination of 1,3-di(4-imidazolino-2-methoxyphenoxy)propane (DMP) in rat, dog and human plasma (50-5000 ng/ml) and urine (0.1-10 micrograms/ml). DMP and DMPent (dimethoxyimidizolinopentamidine, the internal standard), are extracted from alkanized plasma with n-butyl chloride-n-butanol (9:1, v/v). The organic phase is dried under nitrogen, reconstituted in mobile phase, and washed with hexane. Separation is achieved by ion-pair chromatography on a Zorbax Rx C8 column with fluorescence detection. The analysis of pooled plasma (80, 400, and 4000 ng/ml) and urine controls (0.3, 1.6, and 8 micrograms/ml) demonstrated excellent precision and accuracy over a three-day period. The recovery of DMP is > 90% from rat, dog, and human plasma and > 85% from rat and human urine, and 60-70% from dog urine. The limit of quantitation (LOQ) of the assay is 50 ng/ml in rat, dog and human plasma. Using the high-sensitivity assay, the limit of quantitation was decreased to 5, 2 and 0.6 ng/ml in rat, dog and human plasma, respectively. The LOQ of the assay is 0.1 microgram/ml in rat, dog and human urine. The assay was used to determine plasma and urine concentrations of DMP in pharmacokinetic studies in rat and dog.
Assuntos
Antiprotozoários/análise , Pentamidina/análogos & derivados , Administração Oral , Animais , Antiprotozoários/administração & dosagem , Antiprotozoários/sangue , Antiprotozoários/urina , Cromatografia Líquida de Alta Pressão , Cães , Humanos , Indicadores e Reagentes , Injeções Intravenosas , Pentamidina/administração & dosagem , Pentamidina/análise , Pentamidina/sangue , Pentamidina/urina , Controle de Qualidade , Ratos , Espectrometria de FluorescênciaRESUMO
There are no safe and effective oral drugs to treat leishmaniasis and Chagas' disease. The safety, pharmacokinetics, and metabolism of single and multiple oral doses of allopurinol riboside, an investigational antiparasitic agent, were evaluated in a randomized, double-blinded, placebo-controlled study in 32 healthy male volunteers, at levels up to 25 mg/kg q.i.d. for 13 doses. No significant toxicity was detected. Allopurinol riboside peaks in plasma 1.6 hours after administration, has an elimination half-life of 3 hours, and steady-state concentrations in the therapeutic range. However, in contrast to preclinical studies in dogs (plasma levels proportional to oral doses up to 200 mg/kg), we found that plasma levels were unexpectedly low and did not rise with increasing dose. Furthermore, allopurinol and oxypurinol (unanticipated metabolites) were detected at levels proportional to the dose of allopurinol riboside. We present a model that includes incomplete absorption, metabolism of residual drug by enteric flora, and absorption of bacterial metabolites to explain these findings in humans.
Assuntos
Alopurinol/análogos & derivados , Antiprotozoários/farmacocinética , Ribonucleosídeos/farmacocinética , Adolescente , Adulto , Alopurinol/efeitos adversos , Alopurinol/sangue , Alopurinol/farmacocinética , Alopurinol/urina , Antiprotozoários/efeitos adversos , Antiprotozoários/sangue , Antiprotozoários/urina , Método Duplo-Cego , Avaliação de Medicamentos , Meia-Vida , Humanos , Análise dos Mínimos Quadrados , Masculino , Pessoa de Meia-Idade , Oxipurinol/sangue , Purinas/sangue , Ribonucleosídeos/efeitos adversos , Ribonucleosídeos/sangue , Ribonucleosídeos/urinaRESUMO
1H-NMR and MS were employed to identify 13 rat urinary metabolites of 14C-labeled cis-3a,4,5,6,7,7a- hexahydro-3-(1-methyl-5-nitro-1H-imidazol-2-yl)-1,2-benzisoxazole (MK-0436). The major free (unconjugated) metabolite was cis-3a,4,5,6,7, 7a-hexahydro-3-carboxamido-1,2-benzisoxazole; it was also the second most abundant metabolite released during hydrolysis of the conjugated fraction. All other identified metabolites were hydroxylated analogues substituted at C(4)-C(7a) of the cyclohexane ring. the 4-equatorial,5-axial,7a-triol was the second most abundant metabolite excreted in an unconjugated form. Four monohydroxy (5-axial, 6-axial, 6-equatorial, 7-equatorial) metabolites of the drug were identified; they were found in the conjugated fraction only and were released by hydrolysis. The 5-axial hydroxy compound is the major conjugated metabolite and is overall the most abundant of all the metabolites. Six dihydroxy metabolites were identified: one was found exclusively in the free state, three as conjugates only (including the 7-axial,7a-diol, which is the major dihydroxy species), and two both free and conjugated. A second triol was found both free and conjugated.
Assuntos
Antiprotozoários/urina , Nitroimidazóis/urina , Animais , Antiprotozoários/metabolismo , Biotransformação , Hidrólise , Espectrometria de Massas , Nitroimidazóis/metabolismo , Ratos , Ratos EndogâmicosRESUMO
The pharmacokinetics of imidocarb, administered as an IV bolus dose (4 mg/kg), was studied in normal and Escherichia coli endotoxin-induced febrile dogs and goats. In the febrile group, the drug was administered 1 hour after injection of the endotoxin. The plasma and urine concentrations of imidocarb were measured by spectrophotometry. The decline in plasma drug concentrations in both species was analyzed, using a 2-compartment open model. With the exception of the coefficient A and the volume of central compartment, E coli endotoxin-induced fever produced the same changes in kinetic determinants in both species. Fever significantly decreased the distribution rate constant in both dogs (P less than 0.05) and goats (P less than 0.01). The elimination rate constant and, in turn, the half-life were not altered by the endotoxin-induced fever in either species. The volume of distribution at steady-state was significantly lower (P less than 0.01) in the febrile dogs and goats. The body clearance of imidocarb was also significantly lower in the febrile dogs (P less than 0.05) and goats (P less than 0.01). The decreased apparent volume of distribution and lower body clearance of imidocarb could explain the higher plasma values of the drug in the febrile, compared with normal, animals.
Assuntos
Antiprotozoários/metabolismo , Carbanilidas/metabolismo , Doenças do Cão/metabolismo , Cães/metabolismo , Febre/veterinária , Cabras/metabolismo , Imidocarbo/metabolismo , Animais , Antiprotozoários/sangue , Antiprotozoários/urina , Endotoxinas/toxicidade , Escherichia coli , Febre/etiologia , Febre/metabolismo , Meia-Vida , Imidocarbo/análogos & derivados , Imidocarbo/sangue , Imidocarbo/urina , Especificidade da EspécieRESUMO
Metabolite fractions from the urine of a dog dosed with 3a,4,5,6,7a-hexahydro-3-(1-methyl-5-nitro-1H-imidazol-2-yl)-1,2-benzisoxazole (MK-0436) were obtained by the use of high-performance liquid chromatography. These fractions were of suitable purity for structural elucidation. Data obtained by mass spectrometry and NMR spectroscopy allowed the identification of seven major metabolites of this drug. Biotransformation in each case involved hydroxylation (mono or di) of the hexahydrobenzisoxazole ring.
Assuntos
Antiprotozoários/urina , Isoxazóis/urina , Nitroimidazóis/urina , Oxazóis/urina , Animais , Antiprotozoários/metabolismo , Cromatografia Gasosa , Cromatografia Líquida de Alta Pressão , Cães , Cromatografia Gasosa-Espectrometria de Massas , Isoxazóis/metabolismo , Espectroscopia de Ressonância Magnética , Nitroimidazóis/metabolismoRESUMO
The antiprotozoal drug 3a,4,5,6,7,7a-hexahydro-3-(1-methyl-5-nitro-1H-imidazol-2-yl)-1,2-benzisoxazole (I), which exhibits activity against trypanosomiasis, is also antibacterial in vivo. Since the urine from a dog dosed with I showed a broader spectrum of antibacterial activity than I itself, metabolites from this urine were isolated and partially characterized. The metabolites were mono- and dihydroxy-substituted species with the hydroxyl groups on carbons 4--7 of the hexahydrobenzisoxazole ring. These observations led to the synthesis of several such hydroxy derivatives of I, and their properties fully supported the proposed positions of metabolic hydroxylation. One synthetic compound, the 6,7-cis-dihydroxy compound, exhibited higher antibacterial activity against Salmonella schottmuelleri in mice and greater trypanocidal activity in vivo against Trypanosoma cruzi (Brazil strain) than I.