RESUMO
Closantel (CLS) is currently used in programs for the strategic control of gastrointestinal nematodes. CLS is extralabel used in different dairy goat production systems. From available data in dairy cows, it can be concluded that residues of CLS persist in milk. The current work evaluated the concentration profiles of CLS in plasma and milk from lactating orally treated dairy goats to assess the residues pattern in dairy products such as cheese and ricotta. Six (6) female Saanen dairy goats were treated orally with CLS administered at 10 mg/kg. Blood and milk samples were collected between 0 and 36 days post-treatment. The whole milk production was collected at 1, 4, 7, and 10 days post-treatment to produce soft cheese and ricotta. CLS concentrations in plasma, milk, cheese, whey, and ricotta were determined by HPLC. The concentrations of CLS measured in plasma were higher than those measured in milk at all sampling times. However, the calculated withdrawal time for CLS in milk was between 39 and 43 days postadministration to dairy goats. CLS residual concentrations in cheese (between 0.93 and 1.8 µg/g) were higher than those measured in the milk used for its production. CLS concentrations in ricotta were sixfold higher than those in the milk and 20-fold higher than those in the whey used for its production. The persistent and high residual concentrations of CLS in the milk and in the cheese and ricotta should be seriously considered before issuing any recommendation on the extralabel use of CLS in dairy goat farms.
Assuntos
Antinematódeos/farmacocinética , Queijo/análise , Resíduos de Drogas/análise , Cabras/metabolismo , Leite/química , Salicilanilidas/farmacocinética , Animais , Antinematódeos/análise , Antinematódeos/sangue , Feminino , Doenças das Cabras/tratamento farmacológico , Doenças das Cabras/parasitologia , Doenças das Cabras/prevenção & controle , Salicilanilidas/análise , Salicilanilidas/sangueRESUMO
The goal of elimination of the human filariases would benefit greatly from the use of a macrofilaricidal agent. In vivo trials in humans and many experimental animal models suggest that flubendazole (FLBZ) is a highly efficacious macrofilaricide. However, since serious injection site reactions were reported in humans after parenteral FLBZ administration, the search for alternative pharmaceutical strategies to improve the systemic availability of FLBZ and its metabolites has acquired urgency in both human and veterinary medicine. The goal of the current work was to compare the systemic exposure of FLBZ formulated as either an aqueous hydroxypropyl-ß-cyclodextrin (CD) or aqueous carboxymethyl cellulose (CMC) suspension or a Tween 80-based formulation (TWEEN) in rats and jirds (Meriones unguiculatus). Healthy animals of both species were allocated into four experimental groups of 44 animals each: FLBZ-CD oral and FLBZ-CDsc, treated with the FLBZ-CD formulation by the oral or subcutaneous routes, respectively; FLBZ-TWEENsc, dosed subcutaneously with the FLBZ-TWEEN formulation; and FLBZ-CMC oral, treated orally with the FLBZ suspension. The FLBZ dose was 5 mg/kg. FLBZ and its hydrolyzed (H-FLBZ) and reduced (R-FLBZ) metabolites were recovered in plasma samples collected from rats and jirds treated with the different FLBZ formulations. In both species, FLBZ parent drug was the main analyte recovered in the bloodstream. In rats, FLBZ systemic exposure (AUC 0-LOQ) was significantly (P < 0.05) higher after the FLBZ-CD treatments, both oral (4.8 ± 0.9 µg.h/mL) and subcutaneous (7.3 ± 0.6 µg.h/mL), compared to that observed after oral administration of FLBZ-CMC suspension (0.93 ± 0.2 µg.h/mL). The same differences were observed in jirds. In both species, parenteral administration of FLBZ-TWEEN did not improve the systemic availability of FLBZ compared to FLBZ-CDoral treatment. In conclusion, formulation approaches that enhance the availability of flubendazole in the rat and jird may have therapeutic implications for a drug with poor or erratic bioavailability.
Assuntos
Antinematódeos , Mebendazol/análogos & derivados , 2-Hidroxipropil-beta-Ciclodextrina , Animais , Antinematódeos/sangue , Antinematódeos/química , Antinematódeos/farmacocinética , Carboximetilcelulose Sódica/química , Química Farmacêutica , Gerbillinae , Mebendazol/sangue , Mebendazol/química , Mebendazol/farmacocinética , Ratos , Ratos Wistar , beta-Ciclodextrinas/químicaRESUMO
The plasma kinetic profile of moxidectin (MXD) in ewes during the last third of pregnancy was studied after the subcutaneous dose of 0.2 mg/kg of body weight (bw). Two groups of sheep (n = 7) that were equally balanced in body weight were used. Group I (control) was maintained unmated, while Group II (pregnant) was estrous-synchronized and mated with fertile rams. Both groups were maintained under similar conditions regarding management and feeding. When the ewes from Group II fulfilled 120 days of pregnancy, both groups were treated with a subcutaneous injection of 0.2 mg of MXD/kg bw. Blood samples were collected at different set times between 1 h and 40 days post-treatment. After plasma extraction and derivatization, the samples were analyzed using high-performance liquid chromatography with fluorescence detection. A noncompartmental pharmacokinetic analysis was performed, and the data were compared using Student's t-test. The mean pharmacokinetic parameters, including Cmax , Tmax , and the area under the concentration-time curve (AUC), were similar for both groups of sheep. The average of elimination half-life was significantly lower (P = 0.0023) in the pregnant (11.49 ± 2.2 days) vs. the control (17.89 ± 4.84 days) sheep. Similarly, the mean residence time (MRT) for the pregnant group (20.6 ± 3.8 days) was lower (P = 0.037) than that observed in the control group (27.4 ± 9.1 days). It is concluded that pregnancy produces a significant decrease in mean values of half-life of elimination of MXD, indicating that pregnancy can increase the rate of elimination of the drug reducing their permanence in the body.
Assuntos
Antinematódeos/farmacocinética , Macrolídeos/farmacocinética , Ovinos/metabolismo , Animais , Antinematódeos/administração & dosagem , Antinematódeos/sangue , Estudos de Casos e Controles , Feminino , Injeções Subcutâneas/veterinária , Macrolídeos/administração & dosagem , Macrolídeos/sangue , Infecções por Nematoides/tratamento farmacológico , Infecções por Nematoides/prevenção & controle , Infecções por Nematoides/veterinária , Gravidez , Ovinos/parasitologia , Doenças dos Ovinos/tratamento farmacológico , Doenças dos Ovinos/prevenção & controleRESUMO
BACKGROUND: Flubendazole (FLBZ) is a poor water solubility broad-spectrum BZD methylcarbamate anthelmintic compound. Cyclodextrins (CDs) are usually used to increase aqueous solubility of poor hydrosoluble compounds. The comparative in vitro aqueous solubility of FLBZ and other BZD anthelmintics in the presence of hydroxypropyl-ß-cyclodextrin (HPßCD) was evaluated in the current work. Additionally, the comparative pharmacokinetic behaviour of FLBZ (and its metabolites) administered by the intraruminal (i.r.) or intraabomasal (i.a.) routes to sheep as either an aqueous CDs-based solution or a conventional carboximethylcellulose (CMC) suspension was assessed. Drug solubility studies involving albendazole, mebendazole, oxfendazole and FLBZ were performed in an aqueous solution (pH 1.2 or 7.4) with or without HPßCD (10%, w/v). The pharmacokinetic study involved two experiments. Experiment 1: In a crossover study, sheep received either a FLBZ-CDs solution (n = 3) or a FLBZ-CMC suspension (n = 3) by the i.r. route (3.8 mg/kg). The treatment Groups were reversed after a 21-days washout period. Experiment 2: sheep (n = 4) were treated by the i.a. route with the FLBZ-CDs solution (3.8 mg/kg). Plasma and abomasal fluid samples were collected between 0 and 72 h post-treatment. Samples were analysed by HPLC. RESULTS: Improvement of FLBZ aqueous solubility due to CDs resulted markedly higher than that observed for mebendazole and albendazole. However, oppositely to what was expected, the absorption-related pharmacokinetic parameters did not show any marked formulation-dependant effect. After the i.a. administration of FLBZ, the AUC and the Tmax of the parent compound were significantly (P < 0.05) reduced, which is consistent with ruminal bypass. CONCLUSION: The administration of FLBZ as a CDs-based solution, does not seem to achieve great practical relevance for parasite control in sheep.
Assuntos
Antinematódeos/farmacocinética , Ciclodextrinas/química , Mebendazol/análogos & derivados , Doenças dos Ovinos/tratamento farmacológico , Abomaso , Albendazol/farmacocinética , Animais , Antinematódeos/administração & dosagem , Antinematódeos/sangue , Antinematódeos/química , Área Sob a Curva , Benzimidazóis/farmacocinética , Líquidos Corporais/química , Química Farmacêutica , Estudos Cross-Over , Meia-Vida , Mebendazol/administração & dosagem , Mebendazol/sangue , Mebendazol/química , Mebendazol/farmacocinética , Ovinos , Doenças dos Ovinos/parasitologia , SolubilidadeRESUMO
A pharmaco-parasitological assessment of four different albendazole (ABZ) formulations was carried out in lambs infected with multiple resistant gastrointestinal (GI) nematodes. The comparative drug systemic exposure profiles (ABZ sulphoxide plasma concentrations) and anthelmintic efficacies (clinical endpoint measured through the faecal nematode eggs reduction counts) were determined for a reference formulation (RF) and three different test (T1, T2, T3) generic ABZ preparations. Fifty (50) Corriedale lambs naturally infected with multiple resistant GI nematodes were allocated into five experimental groups (n = 10). Animals in each group received treatment with either the RF, one of the test ABZ formulations (5 mg/kg by the intraruminal route) or were kept as untreated control. Blood samples were collected over 48 h post-treatment. ABZ parent drug was not recovered in the bloodstream. The ABZ sulphoxide (ABZSO) and sulphone (ABZSO(2) ) metabolites were measured in plasma by ultraviolet high-performance liquid chromatography over 36-48 h post-treatment. A faecal nematode egg count reduction test (FECRT) was performed at day 10th post-treatment to lambs from all treated and untreated groups, which indicated the predominance of nematodes with high level of resistance to ABZ. Both ABZSO C(max) and AUC(0-LOQ) values obtained for the RF (pioneer product) were significantly higher (P < 0.05) than those obtained for the T1 and T3 preparations. Based on the currently available bioequivalence criteria, the test (generic) ABZ formulations under evaluation could not be considered equivalent to the RF regarding the rate (C(max) ) and extent (AUC(0-LOD) ) of drug absorption (indirectly estimated through the ABZSO metabolite). A large variation in nematode egg counts did not permit to obtain statistically significant differences among formulations. However, a favourable trend in the efficacy against the most resistant nematodes was observed for the formulations with the highest ABZSO systemic exposure.
Assuntos
Albendazol/farmacocinética , Antinematódeos/farmacocinética , Hemoncose/veterinária , Doenças dos Ovinos/tratamento farmacológico , Tricostrongilose/veterinária , Albendazol/sangue , Albendazol/uso terapêutico , Animais , Antinematódeos/sangue , Antinematódeos/uso terapêutico , Disponibilidade Biológica , Química Farmacêutica , Cromatografia Líquida de Alta Pressão , Fezes/parasitologia , Feminino , Hemoncose/sangue , Hemoncose/tratamento farmacológico , Hemoncose/parasitologia , Contagem de Ovos de Parasitas , Ovinos , Doenças dos Ovinos/sangue , Doenças dos Ovinos/parasitologia , Equivalência Terapêutica , Tricostrongilose/sangue , Tricostrongilose/tratamento farmacológico , Tricostrongilose/parasitologiaRESUMO
Moxidectin (MXD) is a milbemycin endectocide compound active at extremely low dosages against a wide variety of nematode and arthropod parasites. Different pharmacological approaches are currently being tested to delay the bile-faecal elimination and to obtain increased systemic availability for endectocide molecules in ruminants. Loperamide (LPM) is an opioid derivative, whose main pharmacological action is to abolish intestinal propulsive peristaltic waves. The influence of LPM on the pattern of faecal excretion of MXD and on its plasma disposition following intravenous (i.v.) and subcutaneous (s.c.) administrations to cattle was evaluated in the current work. Parasite-free calves were treated with MXD given either alone at 200 microg/kg by i.v. (Experiment 1) and s.c. (Experiment 2) administrations or coadministered with LPM subcutaneously injected at 0.4 mg/kg. Blood and faecal samples were collected over a period of 20 (Experiment 1) and 40 (Experiment 2) days post-treatment. The recovered plasma and faecal samples were extracted and analysed by high-performance liquid chromatography (HPLC) using fluorescence detection. Significantly higher MXD plasma concentrations were obtained after the coadministration of MXD + LPM compared with treatments with MXD alone by both routes. The higher MXD plasma concentration profiles measured after the coadministration with LPM accounted for the significantly higher AUC values obtained following the i.v. (> 46%) and s.c. (> 38%) treatments. A reduced MXD body clearance was observed in the presence of LPM. The appearance of MXD in faeces was significantly delayed after the i.v. and s.c. coadministrations of MXD with LPM (T(1/2app)=5.87 and 10.6 h, respectively) than that observed after the treatment with MXD alone (T(1/2app)=3.48 and 5.12 h). A delayed MXD peak concentration in faeces collected from MXD + LPM-treated animals compared with those receiving MXD alone, was observed. The delayed intestinal transit time caused by LPM and a potential competition between MXD and LPM for the P-glycoprotein-mediated bile/intestinal secretion processes, may account for the enhanced MXD systemic availability measured in cattle in the current work.
Assuntos
Antibacterianos/farmacocinética , Antidiarreicos/farmacologia , Antinematódeos/farmacocinética , Bovinos/metabolismo , Loperamida/farmacologia , Animais , Animais Recém-Nascidos , Antibacterianos/administração & dosagem , Antibacterianos/sangue , Antibacterianos/uso terapêutico , Antidiarreicos/administração & dosagem , Antinematódeos/administração & dosagem , Antinematódeos/sangue , Antinematódeos/uso terapêutico , Área Sob a Curva , Disponibilidade Biológica , Doenças dos Bovinos/tratamento farmacológico , Cromatografia Líquida de Alta Pressão/veterinária , Sinergismo Farmacológico , Fezes/química , Infusões Intravenosas/veterinária , Injeções Subcutâneas/veterinária , Loperamida/administração & dosagem , Macrolídeos , Masculino , Infecções por Nematoides/tratamento farmacológico , Infecções por Nematoides/veterináriaRESUMO
The time of parasite exposure to active drug concentrations determines the persistence of the antiparasitic activity of endectocide compounds. This study evaluates the disposition kinetics of moxidectin (MXD) in plasma and in different target tissues following its subcutaneous (s.c.) administration to cattle. Eighteen male, 10-month old Holstein calves weighing 120-140 kg were subcutaneously injected in the shoulder area with a commercially available formulation of MXD (Cydectin 1%, American Cyanamid, Wayne, NJ, USA) at 200 micrograms/kg. Two treated calves were killed at each of the following times post-treatment: 1, 4, 8, 18, 28, 38, 48, 58 and 68 days. Abomasal and small intestine mucosal tissue and fluids, bile, faeces, lung, skin and plasma samples were collected, extracted, derivatized and analysed to determine MXD concentrations by high performance liquid chromatography (HPLC) with fluorescence detection. MXD was extensively distributed to all tissues and fluids analysed, being detected (concentrations > 0.1 ng/g; ng/mL) between 1 and 58 days post-treatment. MXD peak concentrations were attained during the first sampling day. MXD maximum concentration (Cmax) values ranged from 52.9 (intestinal mucosa) up to 149 ng/g (faeces). The mean residence time (MRT) in the different tissues and fluids ranged from 6.8 (abomasal mucosa) up to 11.3 (bile) days. MXD concentrations in abomasal and intestinal mucosal tissue were higher than those detected in plasma; however, there was a high correlation between MXD concentrations observed in plasma and those detected in both gastrointestinal mucosal tissues. MXD concentrations were markedly greater in the mucosa than in its respective digestive fluid (P < 0.01). MXD concentrations in skin were higher than those found in plasma (P < 0.01). Drug concentrations recovered in the dermis were greater than those detected in the hypodermal tissue (P < 0.05). Large concentrations of MXD were excreted in bile and faeces. These findings may contribute to an understanding of the relationship between the kinetic behaviour and the persistence of the antiparasite activity of MXD against different ecto-endoparasites in cattle.