Orientador: Carlos Augusto Araújo Valadão / Banca: Firmino Mársico Filho / Banca: Newton Nunes / Resumo: O amitraz possui efeitos sistêmicos resultantes da atividade intrínseca com receptores adrenérgicos do tipo a-2. Nesse estudo, avaliaram-se os efeitos das injeções epidurais de amitraz (0,1 e 0,4 mg/kg), xilazina (0,05 mg/kg ) ou DMSO 10 % (5,0 mL) sobre a freqüência cardíaca (FC), pressão arterial sistólica (PAS), freqüência respiratória (FR), motilidade ruminal (MR), temperatura retal (TR), tônus do esfíncter anal (TEA), altura de cabeça (AC) e as latências da resposta a estímulos nociceptivos nas regiões da coxa (LECC) e coroa do casco (LRRM) de vacas. Houve redução da FC nos grupos amitraz e xilazina, sendo que nessa última a diminuição foi mais acentuada até os 65 minutos. A MR foi inibida nos grupos amitraz até os 240 minutos e xilazina até 180 minutos. Somente a xilazina reduziu a FR, PAS e AC. A LECC foi maior no grupo xilazina até os 240 minutos e no grupo amitraz (0,4 mg/kg) até os 120 minutos. A LRRM foi maior no grupo xilazina dos 15 aos 55 minutos. No grupo amitraz (0,4 mg/kg) o incremento dessa latência ocorreu entre 25 e 120 minutos. A TR aumentou dos 45 aos 210 minutos após tratamento com xilazina e diminuiu nos outros grupos. Houve relaxamento do esfíncter anal no grupo xilazina durante os 240 minutos. Houve diminuição do TEA do momento 35 ao 120 no grupo amitraz (0,4 mg/kg), quando comparado ao grupo DMSO. Salivação excessiva foi observada após tratamento com xilazina. Os animais dos grupos DMSO e amitraz (0,1 mg/kg) apresentaram atividade de ruminação durante o período de observação. Concluiu-se que, em vacas, o amitraz epidural aumenta a latência de resposta a estímulo nociceptivo, sem induzir efeitos colaterais sistêmicos severos nas doses utilizadas, em comparação à dose de 0,05 mg/kg de xilazina epidural. / Abstract: The amitraz is a formamidine compound widely used in the preventive veterinary medicine as an acaricide in small and large animals. Several reports showed that the effects caused by intravenous or epidural administration of this substance are result of its interaction with a-2 adrenoceptors. In the present study, the clinics, behavioral and antinociceptive effects of epidural injection of amitraz were assessed and compared with the effects caused by xylazine administered by the same route. Amitraz (0,1 or 0,4 mg/kg), xylazine (0,05 mg/kg) and 10% DMSO (5,0 mL) were injected epidurally in 4 cow groups and heart rate (HR), systolic arterial pressure (SAP), respiratory rate (RR), ruminal motility (RM), rectal temperature (RT), head height (HH), anal pressure (AP) and latency to heat-evoked reflexes (LSPR - skin of perineal region; LHWR - hoof withdrawal reflex) were evaluated. The HR decreased in amitraz and xylazine groups, but in this group this effect was more evident until 65 minutes. RM was inhibited by amitraz and xylazine until 240 and 180 minutes, respectively. Only xylazine diminished RR, SAP and HH. The LSPR was prolonged in xylazine group (T5-T240) and amitraz 0,4 group (T25-T120). The LHWR after xylazine treatment increased between 15 and 55 minutes, while in amitraz 0,4 group it was higher than basal values between 25 and 120 minutes. The xylazine raised RT. The values of AP decreased during all experimental period after xylazine injection. The animals that received epidural xylazine had ptialism. All the animals of DMSO and amitraz 0,1 group ruminated during the experiment. We concluded that amitraz (0,1 and 0,4 mg/kg) does not produce severe systemic effects after its epidural use, in cows. Xylazine (0,05 mg/kg) causes mild systemic effects following epidural administration. Amitraz (0,4 mg/kg) induces prolongation of the latency to heat-evoked reflexes, in cows. / Mestre

Made available in DSpace on 2014-06-11T19:23:43Z (GMT). No. of bitstreams: 0 Previous issue date: 2003-03-20Bitstream added on 2014-06-13T20:11:27Z : No. of bitstreams: 1 almeida_rm_me_jabo.pdf: 397967 bytes, checksum: bd42c207ca27e236edf5d9b74ac0d882 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / O amitraz possui efeitos sistêmicos resultantes da atividade intrínseca com receptores adrenérgicos do tipo a-2. Nesse estudo, avaliaram-se os efeitos das injeções epidurais de amitraz (0,1 e 0,4 mg/kg), xilazina (0,05 mg/kg ) ou DMSO 10 % (5,0 mL) sobre a freqüência cardíaca (FC), pressão arterial sistólica (PAS), freqüência respiratória (FR), motilidade ruminal (MR), temperatura retal (TR), tônus do esfíncter anal (TEA), altura de cabeça (AC) e as latências da resposta a estímulos nociceptivos nas regiões da coxa (LECC) e coroa do casco (LRRM) de vacas. Houve redução da FC nos grupos amitraz e xilazina, sendo que nessa última a diminuição foi mais acentuada até os 65 minutos. A MR foi inibida nos grupos amitraz até os 240 minutos e xilazina até 180 minutos. Somente a xilazina reduziu a FR, PAS e AC. A LECC foi maior no grupo xilazina até os 240 minutos e no grupo amitraz (0,4 mg/kg) até os 120 minutos. A LRRM foi maior no grupo xilazina dos 15 aos 55 minutos. No grupo amitraz (0,4 mg/kg) o incremento dessa latência ocorreu entre 25 e 120 minutos. A TR aumentou dos 45 aos 210 minutos após tratamento com xilazina e diminuiu nos outros grupos. Houve relaxamento do esfíncter anal no grupo xilazina durante os 240 minutos. Houve diminuição do TEA do momento 35 ao 120 no grupo amitraz (0,4 mg/kg), quando comparado ao grupo DMSO. Salivação excessiva foi observada após tratamento com xilazina. Os animais dos grupos DMSO e amitraz (0,1 mg/kg) apresentaram atividade de ruminação durante o período de observação. Concluiu-se que, em vacas, o amitraz epidural aumenta a latência de resposta a estímulo nociceptivo, sem induzir efeitos colaterais sistêmicos severos nas doses utilizadas, em comparação à dose de 0,05 mg/kg de xilazina epidural. / The amitraz is a formamidine compound widely used in the preventive veterinary medicine as an acaricide in small and large animals. Several reports showed that the effects caused by intravenous or epidural administration of this substance are result of its interaction with a-2 adrenoceptors. In the present study, the clinics, behavioral and antinociceptive effects of epidural injection of amitraz were assessed and compared with the effects caused by xylazine administered by the same route. Amitraz (0,1 or 0,4 mg/kg), xylazine (0,05 mg/kg) and 10% DMSO (5,0 mL) were injected epidurally in 4 cow groups and heart rate (HR), systolic arterial pressure (SAP), respiratory rate (RR), ruminal motility (RM), rectal temperature (RT), head height (HH), anal pressure (AP) and latency to heat-evoked reflexes (LSPR - skin of perineal region; LHWR - hoof withdrawal reflex) were evaluated. The HR decreased in amitraz and xylazine groups, but in this group this effect was more evident until 65 minutes. RM was inhibited by amitraz and xylazine until 240 and 180 minutes, respectively. Only xylazine diminished RR, SAP and HH. The LSPR was prolonged in xylazine group (T5-T240) and amitraz 0,4 group (T25-T120). The LHWR after xylazine treatment increased between 15 and 55 minutes, while in amitraz 0,4 group it was higher than basal values between 25 and 120 minutes. The xylazine raised RT. The values of AP decreased during all experimental period after xylazine injection. The animals that received epidural xylazine had ptialism. All the animals of DMSO and amitraz 0,1 group ruminated during the experiment. We concluded that amitraz (0,1 and 0,4 mg/kg) does not produce severe systemic effects after its epidural use, in cows. Xylazine (0,05 mg/kg) causes mild systemic effects following epidural administration. Amitraz (0,4 mg/kg) induces prolongation of the latency to heat-evoked reflexes, in cows.

Made available in DSpace on 2014-06-11T19:23:42Z (GMT). No. of bitstreams: 0 Previous issue date: 2007-07-27Bitstream added on 2014-06-13T20:30:35Z : No. of bitstreams: 1 escobar_a_me_jabo.pdf: 469077 bytes, checksum: 4db0fafd9bab3f1993358cf18a557b9d (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Foram avaliados os efeitos cardiovasculares e comportamentais após a administração intravenosa de amitraz ou xilazina em oito gatos. Todos os animais foram submetidos aos três tratamentos, a saber: GXil - 1 mg/kg de xilazina; GAmz - 1 mg/kg de amitraz em diluente lipídico; e GDil - volume de diluente lipídico idêntico ao utilizado nos animais tratados com amitraz, respeitando-se um intervalo mínimo de 15 dias entre eles. Imediatamente antes dos tratamentos, avaliaram-se à pressão arterial sistólica (PAS), temperatura retal (T), freqüência respiratória (f), ritmo, freqüência (FC), índice (IC) e contratilidade cardíaca. Os demais registros foram realizados aos 5, 10, 15, 20, 30, 40, 50 e 60 minutos após os tratamentos. Empregou-se análise de variância (ANOVA) de uma única via e teste de Friedman, ambos seguidos pelo teste de Tukey (p=0,05), respectivamente para os dados paramétricos e não-paramétricos. Tanto o amitraz como a xilazina causaram bloqueios atrioventriculares de 1º grau e redução da FC, frações de ejeção (FE) e de encurtamento (FS), IC, PAS e T. Complexos ventriculares prematuros foram observados após a aplicação de amitraz ou do diluente, e a f aumentou. O amitraz induziu sedação menos intensa do que a xilazina. Conclui-se que ambos induzem bradicardia e BAV de 1º grau, observando-se maior depressão da contratilidade cardíaca para a xilazina. A dose empregada do amitraz produz efeito sedativo em gatos. / To evaluate the cardiovascular and behavioral alterations, eight cats were submitted to amitraz or xylazine intravenous injection: GXil - 1 mg/kg of xylazine; GAmz - 1 mg/kg of amitraz; and GDil - diluent in equal volume used on GAmz. The same cats were used after a 15 day interval. Systolic arterial blood pressure (SAP), temperature (T), respiratory (RR) and heart rates (HR), cardiac index (CI), rhythm and contractility (ejection fraction - EF and shortening fraction - SF) were measured before treatments and 5, 10, 15, 20, 30, 40, 50 and 60 minutes after each treatment. One way analysis of variance (ANOVA) and Friedman test, followed by Tukey test (p=0.05), were used to compare parametric and non-parametric data, respectively. Amitraz and xylazine induced first-degree A-V block, decreased HR, EF, SF, CI, SAP and T. Ventricular premature complexes were noted after amitraz or diluent injection, and RR increased. Amitraz induced a lower sedative effect compared to xylazine. It was concluded that both a2-agonists produce bradycardia and first-degree A-V block, but xylazine causes greater cardiac contractility depression. Additionally, amitraz produces a sedative effect in cats.

Orientador: Nelson Eduardo Durán Caballero / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Química / Made available in DSpace on 2018-08-27T11:57:43Z (GMT). No. of bitstreams: 1 BerniNeto_EliasAntonio_D.pdf: 2747484 bytes, checksum: 572541fe31adfbc199cbcb02da6c1cbe (MD5) Previous issue date: 2014 / Resumo: O Brasil se destaca por ter uma das maiores pecuárias bovinas do mundo,movimentando cerca de R$ 164 bilhões ao ano. Contudo, este setor apresenta ainda algumas dificuldades, principalmente relacionadas com a sanidade dos animais. Dentre as principais patologias responsáveis por perdas podemoscitar o ataque de ectoparasitas,como o Boophilumicroplus, que gera perdas da ordem de US$ 4 bilhão ao ano, e a mastite bovina (inflamação no ubre de vacas) causada por microorganismos como Staphylococcus aureus e a Escherichia colie que gera perdas nos valores de U$ 185 por animal ao ano. Baseado nesses fatos, a área de nanoliberação ou drug release foi escolhida como alternativa para aumentar a eficácia dos carrapaticidas e dos medicamentos usados no combate a mastite. Com o uso de nanopartículas poliméricas de poli(?-caprolactona) (PCL) eutilizando a técnica de nanoprecipitação ou deslocamento do solvente recobertas com o polímero quitosana, foi possível aumentar tanto a estabilidade como asolubilidade dos ativos, bem como diminuir sua toxicidade contra células 3T3. Foram estudados 4 sistemas distintos, QS_PCLnp (sem ativo), QS_PCLnp _ami (contendo o ativo amitraz), QS_PCLnp_flu (contendo o ativo fluazuron) e QS_PCLnp_vio (contendo o ativo violaceína). O sistema QS_PCLnp_vioapresentou um tamanho de 260±10 nm e carga superficial de +30±2 mV, com uma concentração final de violaceína de 180 ?g mL-1eeficiência de 91±1% para uma capacidade de encapsulamento de 11±1% em relação a massa de PCL, sendo testado contra as bactérias E. coli e S. aureus no combate a Mastite bovina. O sistemaQS_PCLnp_amiapresentou o tamanho de 275±30 nm e carga superficial de +43±7 mV, com uma concentração final de amitraz de 1,0 mg mL-1e eficiência de 77±1% para uma capacidade de encapsulamento de 39±1% com relação a massa de PCL. Já o sistema QS_PCLnp_flu apresentou o tamanho de 295±35nm com um potencial zeta de +44±10econcentração de 0,5 mg mL-1 de fluazurono, onde obteve-se uma eficiência de 89±1% para uma capacidade de encapsulamento de 22±1% com relação a massa de PCL. Sendo que os sistemas QS_PCLnp_ami e QS_PCLnp_flu foram usados no combate ao carrapato B. microplus. Em todos os sistemas contendo ativos foi observado que os mesmos estavam dispersos molecularmente na matriz polimérica interna de PCL bem como na camada superficial de quitosana, influenciando na estabilidade estérica das nanopartículas no pH acima de 7. Todos os sistemas se mostraram estáveis em soluções salinas deconcentração de 1,25 mol L-1de NaCl e com o aumento da temperatura até 50°C. No estudo da mastite,o sistema QS_PCLnp_vio mostrou uma maior ação contra a S. aureus, enquanto que a violaceína pura se mostrou mais eficaz contra a E. coli,resultados que possibilitam um estudo de um sistema híbrido contendoQS_PCLnp_vio e violaceína pura. No caso do combate ao carrapato B. microplus o uso dos sistemas QS_PCLnp_ami e QS_PCLnp_flu em conjunto, possibilitou uma dose menor do ativo fluazuron do que a praticada comercialmente, deixando o animal livre de carrapatos por um período de 28 dias, necessitando de espaços maiores entre os banhos daqueles praticados atualmente / Abstract: Brazil plays a pivotal role in livestock market, moving around R$ 164 billions per year. However, this market shows yet some difficulties, mainly related to the health of animals being the main pathologies which affect the ectoparasites such as Boophilus microplus that generates losses of US$ 4 billion per year, and bovine mastitis (inflammation of the udders of cows) caused by microorganisms such as Staphylococcus aureus and Escherichia coli, that generates losses in the amounts of US$ 185 per cow per year. For this reason the drug release was chosen as an alternative to increase the effectiveness of acaricides and drugs used against bovine mastitis. Using polymeric nanoparticles of poly (?-caprolactone) (PCL) coated with the polymer chitosan, and synthesized by displacement solvent technique was possible to increase both stability and solubility assets as well as decreasing its toxicity against 3T3 cells. In this work, 4 different systems were studied, QS_PCLnp (without assets), QS_PCLnp_vio (containing the active violacein) QS_PCLnp_ami (containing the active amitraz) and QS_PCLnp_flu (containing the active fluazuron). The QS_PCLnp_vio system showed a size of 260±10 nm and surface charge of +30±2 mV, with a final concentration of 180 mg mL-1 of violacein and efficiency of 91±1% for a loading capacity of 11±1% compared with PCL mass, this system were being tested against the bacteria S. aureus and E. coli against bovine mastitis. The QS_PCLnp_ami system shows a size of 275±30 nm and surface charge of +43±7 mV, with a final concentration of 1.0 mg mL-1 of amitraz, and an efficiency of 77±1% for a loading capacity of 39±1 % compared with PCL mass, while QS_PCLnp_flu shows a size of 295±35 nm and surface charge of +44±10 mV and 0.5 mg ml-1 of fluazuron, which gave an efficiency of 89±1% for a loading capacity of 22±1% compared with PCL mass. Both system QS_PCLnp_ami and QS_PCLnp_flu were used against B. microplus. All systems shows molecularly dispersed active compound in the polymer matrix of PCL inside and the surface layer of chitosan influencing the steric stability of nanoparticles in pH above 7. All systems were stable in saline concentration of 1.25 mol L-1 of NaCl and with temperature increase up to 50°C. In the study of mastitis, the QS_PCLnp_vio system showed greater activity against S. aureus, while the pure violacein is more effective against E. coli. This result motivates a study of a hybrid system contain QS_PCLnp_vio and pure violacein. In the case of B. microplus tick were used QS_PCLnp_ami and QS_PCLnp_flu together, which provided a lower dose of the active fluazuron than commercially practiced, leaving the animal free of ticks for a period of 28 days, requiring larger spaces between the bathing those currently practiced nowadays / Doutorado / Físico-Química / Doutor em Ciências

Made available in DSpace on 2016-01-26T18:55:45Z (GMT). No. of bitstreams: 1 Dissertacao Cleidemar.pdf: 291699 bytes, checksum: 46535cd36bde0f3bcd3e5d22ca0f3899 (MD5) Previous issue date: 2008-03-28 / The objective was to validate a sensitive, single, rapid and low cost analytical method is presented for determination of amitraz concentration in cat plasma samples using gas chromatography with capillary column and thermionic specific detector (GC-TSD). The method was linear between 20 to 400 ng ml-1 with regression coefficients corresponding to 0.9987 and the coefficient of variation of the points of the calibration curve lower than 20%. The detection limits and quantification were 10 and 20 ng ml-1 respectively. The proposed method was useful and efficient for detection of the amitraz in the plasma of cats intoxicated with this product in a dipping bath. / O objetivo foi validar um método analítico simples, rápido e de baixo custo para determinação da concentração de amitraz no plasma de gatos intoxicados experimentalmente através de banho, empregando-se a cromatografia gasosa com coluna capilar e detector termiônico específico (CG-DTE). O método mostrou-se linear na faixa entre 20 a 400 ng/mL com coeficiente de correlação igual a 0,9987 e o coeficiente de variação dos pontos da curva de calibração abaixo de 15%. Os limites de detecção e quantificação foram 10 ng/mL e 20 ng/mL respectivamente. A metodologia empregada se mostrou útil e eficiente para detecção do amitraz no plasma de gatos intoxicados com este produto.

Made available in DSpace on 2016-07-18T17:53:18Z (GMT). No. of bitstreams: 1 Dissertacao Cleidemar.pdf: 291699 bytes, checksum: 46535cd36bde0f3bcd3e5d22ca0f3899 (MD5) Previous issue date: 2008-03-28 / The objective was to validate a sensitive, single, rapid and low cost analytical method is presented for determination of amitraz concentration in cat plasma samples using gas chromatography with capillary column and thermionic specific detector (GC-TSD). The method was linear between 20 to 400 ng ml-1 with regression coefficients corresponding to 0.9987 and the coefficient of variation of the points of the calibration curve lower than 20%. The detection limits and quantification were 10 and 20 ng ml-1 respectively. The proposed method was useful and efficient for detection of the amitraz in the plasma of cats intoxicated with this product in a dipping bath. / O objetivo foi validar um método analítico simples, rápido e de baixo custo para determinação da concentração de amitraz no plasma de gatos intoxicados experimentalmente através de banho, empregando-se a cromatografia gasosa com coluna capilar e detector termiônico específico (CG-DTE). O método mostrou-se linear na faixa entre 20 a 400 ng/mL com coeficiente de correlação igual a 0,9987 e o coeficiente de variação dos pontos da curva de calibração abaixo de 15%. Os limites de detecção e quantificação foram 10 ng/mL e 20 ng/mL respectivamente. A metodologia empregada se mostrou útil e eficiente para detecção do amitraz no plasma de gatos intoxicados com este produto.

The diploma thesis was focused on the possibility to control Varroa destructor in honeybees by using natural varroacides. In the literary section were processed findings about drugs and in the practical part there were described and evaluated the results. During the experiment the effectiveness of formic acid and fluvalinate and effectiveness of oxalic acid and amitraz were compared. Statistical evaluation of results has found that formic acid reached 78,6% efficiency, and oxalic acid on average, 93,8% efficiency, and this efficiency was equal or statistically insignificantly slightly higher compared to synthetic alternatives. Any negative effects of organic acids on the status and development of colonies were observed. Experiment results are particularly important for the treatment of resistant populations of mites and prevent cumulative acaricides residues in bee products.

Made available in DSpace on 2014-06-11T19:24:00Z (GMT). No. of bitstreams: 0 Previous issue date: 2004Bitstream added on 2014-06-13T19:51:03Z : No. of bitstreams: 1 andrade_sf_dr_botfmvz.pdf: 2228707 bytes, checksum: 4915d934794c6f04008560ac6b01322e (MD5) / Este trabalho teve por objetivo estudar a intoxicação experimental por amitraz em gatos e comparar a eficácia do tratamento entre dois antagonistas a2-adrenérgicos, ioimbina e atipamezole. Para tanto, foram avaliados os efeitos clínicos e toxicológicos do amitraz por via intravenosa (IV) em gatos, incluindo a medida de pressão arterial sistólica, eletrocardiograma, níveis séricos de glicose, insulina e cortisol, eritrograma, leucograma, além da avaliação das funções renal e hepática. Foram utilizados 32 gatos, divididos aleatoriamente em 4 grupos iguais (n=8), sendo que ao grupo C (controle) não foi administrado nenhum fármaco, porém realizaram-se todas as aferições e exames nos mesmos intervalos de tempos, dos grupos intoxicados. Aos do grupo A foi administrado amitraz na dose 1 mg/kg, IV, a 1,5%; aos do grupo AI amitraz nas mesmas dose e concentração do grupo A e 60 minutos após, ioimbina na dose 0,1 mg/kg, IV, a 2 mg/mL; e aos do grupo AA, amitraz nas mesmas dose e concentração do grupo A e 60 minutos após, atipamezole na dose de 0,2 mg/kg, IV, a 5 mg/mL. Foram aferidos os seguintes parâmetros nos intervalos de tempo 0, 30, 60,120, 180, 240 e 360 min após a administração do amitraz: temperatura (T), freqüência respiratória (FR), freqüência cardíaca (FC), pressão arterial sistólica (PAS), eletrocardiograma (ECG), diâmetro pupilar (DP), grau de sedação (GS) e tempo médio de recuperação da sedação (TMRS) considerado como o tempo gasto, em minutos, pelo animal para se levantar após a administração do amitraz e após a administração do antagonista a2- adrenérgico, ioimbina ou atipamezole. Foram coletadas amostras de sangue por venopuncão da jugular ou cefálica 24 horas antes e depois da intoxicação para realização de eritrograma, leucograma, uréia, creatinina, alanina aminotransferase... / This work studied the experimental intoxication for amitraz in cats and compared the effectiveness of the treatment between two a2-adrenergics antagonists, yohimbine and atipamezole. For so much, they were appraised the clinical and toxicological effects of the amitraz by intravenous route (IV), including the measure of systolic arterial pressure, electrocardiogram, serum glucose, insulin and cortisol levels, red and white blood cell counts, besides the evaluation of the renal and hepatic functions. Thirty two cats were used, aleatory divided in 4 groups (n=8). The group C (control) wasn't receive any drug, however all the exams (physical and laboratorial) were made respecting the same intervals used for the intoxicated groups. Amitraz was administered at the dose 1 mg/kg (1,5%), IV, on group A; on group AI, amitraz in the same dose and concentration of the group A and 60 minutes after, yohimbine at the dose 0,1 mg/kg (2 mg/mL), IV; and on group AA, amitraz in the same dose and concentration of the group A and 60 minutes after, atipamezole at the dose 0,2 mg/kg (5 mg/mL), IV. The following parameters were checked in the intervals of time 0, 30, 60,120, 180, 240 and 360 min after the administration of the amitraz: temperature (T), respiratory rate (RR), heart rate (HR), systolic arterial pressure (SAP), electrocardiogram (ECG), diameter pupilar (DP), degree of sedation (DS) and medium interval for sedation return (MISR) considered as the time, in minutes, for the animal to get up after the administration of the amitraz and after the a2-adrenergic antagonists administration, yohimbine or atipamezole. Blood samples were collected by jugular or cephalic puncture 24 hours before and after the intoxication for red blood cell (RBC) count, white blood cell (WBC) count, urea, creatinine, alananine aminotransferase (ALT) and aspartate aminotransferase... (Complete abstract click electronic address below)

This study considered the use of urea eutectics as fast release solid dosage carrier forms for the acaricide N-methylbis (2,4-xylyliminomethyl) methylamine (AmitrazTM). Wettol D2 and Arkopal N090 were chosen as the wetting agent and dispersants respectively. Their optimum levels were determined as the surfactant concentrations that yielded a minimum in the dispersion viscosity of a concentrated (30% m/m) Amitraz suspension. The optimum dosage levels were found to be ca. 2% Arkopal N090 and ca. 1% Wettol D2. Eutectic phase diagrams were obtained using the melting-cooling method. The components were ground together into a fine powder and heated in a glass tube immersed in a silicon oil bath. The liquid was allowed to cool down and solidify at ambient conditions. The time-dependant temperature change of the sample was tracked with a thermocouple. The data was captured in real time on a personal computer and analysed using an Excel spreadsheet programme. The melt-cast method was used to prepare eutectic mixtures. They were characterised using DSC, DTA, XRD and Light Microscopy. The XRD peaks showed the presence of the two separate crystal structures for the eutectic mixture constituents. The urea – CaBr2.2H2O combination was initially considered as carrier for Amitraz. However, this eutectic system was found to be too hygroscopic. Small additions of PEG 6000 improved the tablet strength but decreased the dissolution rate. Urea and acetamide formed a eutectic at ± 46oC with a composition of ca. 40 % m/m urea. Unfortunately acetamide is a suspected carcinogen. Therefore the urea - 1,3-dimethylurea was selected as Amitraz carrier system instead. The eutectic mixture comprised 40% m/m urea and 60% m/m 1,3-dimethylurea, which melt at ± 56oC. The melt-press method was used to prepare Amitraz containing pellets measuring 5 mm thick and 33 mm ö and weighing about 5,0 g. It was possible to suspend Amitraz powder in the eutectic melt mixture provided it remained in powder form. However, when liquefied (by melting), phase separation occurred. Thus the temperature of the eutectic mixture should be kept below the 80oC melting point of Amitraz. The dissolution tests were performed in a 10-liter Pyrex glass beaker with normal tap water (± 25oC). The time taken for complete dissolution was measured with a stopwatch. These results were confirmed with turbidity tests. Starch-based super disintegrants were used in an attempt to enhance the dissolution rate of the pellets. Explotab® improved the dissolution rate of 30% and 40% m/m Amitraz formulations slightly. The best formulation obtained in this study had the following composition (in m/m): 30% Amitraz; 8% CaCO3; 1 % Wettol D2; 2% Arkopal N090; 10% Explotab® and 49% urea – 1,3-dimethylurea eutectic. Such tablets disintegrated within 6,5 minutes when suspended in water. / Dissertation (MSc (Applied Science))--University of Pretoria, 2007. / Chemical Engineering / MSc / unrestricted

This thesis analyzes mixtures of neem oil and amitraz as alternative control for Varroa destructor, a major pest of Apis mellifera, under different agricultural settings. In organic and conventional farms, the different treatments were applied in colonies to determine impacts on mite loss, colony strength, and honey yield. The results demonstrated neem to have the least effective control on mite mortality, while the neem and amitraz mixture had the most. Furthermore, no long term impacts on queen fecundity and colony strength were noticed between treatments. However, queen fecundity and honey yield was significantly higher in sites with higher flower abundance and diversity, demonstrating higher colony strength in these sites. Further understanding of the relationship between apiculture and agricultural management is vital for conservation of pollinator health and associated habitats.