Perfil farmacocinético e atividade ectoparasiticida de uma nova molécula (Arilpirazol) em bovinos
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Data
2018-10-19
Autores
Gomes, Lucas Vinicius Costa [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
Com o aumento da resistência frente a maior parte dos ectoparasiticidas, novos métodos de controle para os principais parasitos de bovinos, tais como novas classes de terapêuticos são urgentemente necessários. Como parte de um programa integrado para endereçar essa demanda, foram realizados estudos para avaliar o perfil farmacocinético de uma formulação não comercializada a base de arilpirazol (nome comum sisapronil), bem como os efeitos terapêutico e residual contra Rhipicephalus (Boophilus) microplus, Haematobia irritans, larvas de Dermatobia hominis e larvas de Cochliomyia hominivorax. Em todos os estudos, os animais receberam pela via subcutânea, 2,0mg/kg de peso vivo do princípio ativo. Para avaliação do perfil farmacocinético, amostras de sangue foram obtidas nos dias 1, 3, 5, 7, 14, 21, 28, 42, 56, 70, 84, 98, 112, 126 e 140 pós-tratamento. Não foram identificadas concentrações da molécula nos momentos pré-tratamento, bem como não foram observadas alterações sistêmicas ou locais nos animais submetidos ao estudo, após a administração do arilpirazol. De acordo com os resultados de farmacocinética, o sisapronil alcançou uma concentração máxima de 74,8 ng/mL (Cmax), detectada em 15,8 dias (Tmax), e meia vida de eliminação de 23,0 dias. Um estudo para avaliar a atividade carrapaticida do arilpirazol contra R. (B.) microplus foi realizado em bovinos naturalmente infestados. Para tal, 20 animais, foram randomizados em dois grupos (T01: controle e T02: arilpirazol), de acordo com as contagens de carrapatos obtidas no pré-tratamento. Percentuais de eficácia foram calculados no 3° e 7° dia pós-tratamento (DPT), e posteriormente, semanalmente até 91° DPT. O grupo tratado com sisapronil atingiu percentuais de eficácia superiores a 90,00% entre o 7° e o 63° DPT. Um outro estudo realizado para avaliar a eficácia mosquicida contra H. irritans (mosca-do-chifre), 30 bovinos naturalmente infestados foram randomizados em dois grupos de acordo com a média aritmética obtida das contagens de moscas antes do tratamento (D-2 e D-1). Os percentuais de eficácia foram calculados nos dias 3,7,14,21,28 e 35 após o tratamento, sendo que a eficácia máxima observada foi de 89,73% no 3° DPT. Para avaliar a eficácia contra larvas de D. hominis, dois grupos, de 10 animais cada, naturalmente infestados foram utilizados. O sisapronil atingiu 100,00% de eficácia entre o 14° e 28° DPT e permaneceu acima de 90,00% até 63° DPT. No estudo para avaliar a eficácia contra larvas de C. hominivorax, 30 bovinos orquiectomizados foram distribuídos em dois grupos com 15 animais cada. Considerando à presença de miíase ativa avaliada entre o 1° e 15° DPT, o sisapronil alcançou 100.00% de eficácia após o 10° DPT. Bovinos medicados com arilpirazol apresentaram quantificações de ectoparasitos estatisticamente inferiores (p≤ 0.05) às do grupo controle em todos os estudos conduzidos. Em síntese, arilpirazol (sisapronil), na dose e via empregadas, constitui uma alternativa promissora para o controle e tratamento dos principais ectoparasitos que acometem os bovinos.
With the increase in ectoparasite resistance to major classes of ectoparasiticides, new control methods for main bovine parasites, such as new classes of therapeutics, are urgently needed. As part of an integrated program to address this demand, studies have been conducted to evaluate the pharmacokinetic profile of a non-marketed formulation based on arylpyrazole (common name sisapronil), as well as the therapeutic and residual effects against Rhipicephalus (Boophilus) microplus, Haematobia irritans, larvae of Dermatobia hominis and larvae of Cochliomyia hominivorax. In all the studies, the animals received by the subcutaneously, 2.0mg / kg of the active. For evaluation of the pharmacokinetic profile, blood samples were obtained on days 1, 3, 5, 7, 14, 21, 28, 42, 56, 70, 84, 98, 112, 126 and 140 post-treatment. No concentrations of the molecule were identified at pre-treatment times, nor were systemic or local reaction observed in the animals submitted to the study after arylpyrazole administration. According to the pharmacokinetic results, sisapronil reached a maximum concentration of 74.8 ng/mL (Cmax), detected at 15.8 days (Tmax), and elimination half-life of 23.0 days. A study to evaluate the acarpyrazole activity of arylpyrazole against R. (B.) microplus was carried out on naturally infested cattle. For such, 20 animals were randomized into two groups (T01: control and T02: arylpyrazole), according to the pre-treatment tick counts. Efficacy percentages were calculated on the 3rd and 7th day post-treatment (DPT), and thereafter, weekly up to 91st DPT. The sisapronil treated group achieved efficacy percentages greater than 90.00% between 7th and 63rd DPT. Another study conducted to evaluate the efficacy against H. irritans (horn fly), 30 naturally infested cattle were randomized into two groups according to the arithmetic mean obtained from pre-treatment flies counts (D-2 and D-1). Efficacy percentages were calculated on days 3, 7, 14, 21, 28 and 35 post-treatment, and the maximum efficacy observed was 89.73% in the 3rd DPT. To evaluate the efficacy against larvae of D. hominis, two groups of 10 naturally infected animals were used. Sisapronil achieved 100.00% efficacy between the 14th and 28th DPT and remained above 90.00% up to 63rd DPT. In the study to evaluate the efficacy against C. hominivorax larvae, 30 orchiectomized cattle were distributed into two groups with 15 animals each. Considering the presence of active myiasis evaluated between the 1st and 15th DPT, sisapronil reached 100.00% efficacy after the 10th DPT. Cattle treated with arylpyrazole showed statistically lower ectoparasite (p≤0.05) quantifications than the control group in all the studies conducted. In summary, arylpyrazole (sisapronil), at the dose and via employed, is a promising alternative for the control and treatment of the main ectoparasites that affect cattle.
With the increase in ectoparasite resistance to major classes of ectoparasiticides, new control methods for main bovine parasites, such as new classes of therapeutics, are urgently needed. As part of an integrated program to address this demand, studies have been conducted to evaluate the pharmacokinetic profile of a non-marketed formulation based on arylpyrazole (common name sisapronil), as well as the therapeutic and residual effects against Rhipicephalus (Boophilus) microplus, Haematobia irritans, larvae of Dermatobia hominis and larvae of Cochliomyia hominivorax. In all the studies, the animals received by the subcutaneously, 2.0mg / kg of the active. For evaluation of the pharmacokinetic profile, blood samples were obtained on days 1, 3, 5, 7, 14, 21, 28, 42, 56, 70, 84, 98, 112, 126 and 140 post-treatment. No concentrations of the molecule were identified at pre-treatment times, nor were systemic or local reaction observed in the animals submitted to the study after arylpyrazole administration. According to the pharmacokinetic results, sisapronil reached a maximum concentration of 74.8 ng/mL (Cmax), detected at 15.8 days (Tmax), and elimination half-life of 23.0 days. A study to evaluate the acarpyrazole activity of arylpyrazole against R. (B.) microplus was carried out on naturally infested cattle. For such, 20 animals were randomized into two groups (T01: control and T02: arylpyrazole), according to the pre-treatment tick counts. Efficacy percentages were calculated on the 3rd and 7th day post-treatment (DPT), and thereafter, weekly up to 91st DPT. The sisapronil treated group achieved efficacy percentages greater than 90.00% between 7th and 63rd DPT. Another study conducted to evaluate the efficacy against H. irritans (horn fly), 30 naturally infested cattle were randomized into two groups according to the arithmetic mean obtained from pre-treatment flies counts (D-2 and D-1). Efficacy percentages were calculated on days 3, 7, 14, 21, 28 and 35 post-treatment, and the maximum efficacy observed was 89.73% in the 3rd DPT. To evaluate the efficacy against larvae of D. hominis, two groups of 10 naturally infected animals were used. Sisapronil achieved 100.00% efficacy between the 14th and 28th DPT and remained above 90.00% up to 63rd DPT. In the study to evaluate the efficacy against C. hominivorax larvae, 30 orchiectomized cattle were distributed into two groups with 15 animals each. Considering the presence of active myiasis evaluated between the 1st and 15th DPT, sisapronil reached 100.00% efficacy after the 10th DPT. Cattle treated with arylpyrazole showed statistically lower ectoparasite (p≤0.05) quantifications than the control group in all the studies conducted. In summary, arylpyrazole (sisapronil), at the dose and via employed, is a promising alternative for the control and treatment of the main ectoparasites that affect cattle.
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Palavras-chave
Fenilpirazol, Sisapronil, Carrapato bovino, Berne, Mosca, Phenylpyrazole, Cattle Tick, Grub, Fly