Intra-articular concentration of gentamicin administered by intravenous regional limb perfusion in healthy horses

EnglishIntravenous regional limb perfusion (IRLP) is an efficient method to treat horses with synovial infections. However, information on the dose, volume, and intervals of administration is lacking. The aim of this study was to evaluate the intra-articular concentration of gentamicin administered by IRLP in horses over 24 h post-administration and evaluate the influence of the total perfused volume. Twenty horses were assigned to two treatment groups. Gentamicin 60 group (G60, n=10) and Gentamicin 250 group (G250, n=10) received IRLP of 6.6 mg/kg of gentamicin diluted in Ringer’s lactate for a total volume of 60 ml (G60) and 250 ml (G250), respectively. Synovial fluid harvests were performed in the metacarpophalangeal joint before (0) and 4, 8, 12, 16, 20, and 24 hours after IRLP. Agar diffusion was the assay for measuring gentamicin concentrations. Four hours after IRLP, the intra-articular concentration of gentamicin was 47.58±49.21 μg/ml in G60 and 10.92±6.11 μg/ml in G250. During the 24 h of harvest, the intra-articular concentration of gentamicin remained above the minimum inhibitory concentration for horses (MIC; 2 μg/ml) in both experimental groups. In G60, the concentration of gentamicin in synovial fluid reached the maximal concentration and remained 8 to 10-fold higher than the MIC (Cmax: 16 to 20 μg/ml) during 12 h after IRLP. These findings support that IRLP with 6.6 mg/kg of gentamicin diluted to a volume of 60 ml promotes intra-articular concentrations higher than 250 ml, remaining above the MIC for 24 h and at the maximum concentration for 12 h portuguesA perfusao regional intravenosa (PRI) em membros de equinos e um metodo comprovadamente eficiente para o tratamento de infeccoes sinoviais, porem ainda existem lacunas quanto a dose, volume e intervalos de administracao a serem utilizados. Neste estudo, objetivou-se avaliar a concentracao intra-articular da gentamicina administrada por PRI em equinos, ao longo de 24 horas pos-administracao, bem como avaliar a influencia do volume total perfundido. Vinte equinos foram distribuidos em dois grupos experimentais, Grupo Gentamicina 60 (G60) e Grupo Gentamicina 250 (G250), representados por 10 equinos em cada grupo que receberam, por PRI, 6,6 mg/kg de gentamicina diluida em Ringer lactato para um total de 60 ml (G60) ou 250 ml (G250). As colheitas de liquido sinovial foram realizadas, na articulacao metacarpo-falangeana, antes do inicio do experimento e apos 4, 8, 12, 16, 20, e 24 horas. Difusao em agar foi o metodo para doseamento das concentracoes de gentamicina. Quatro horas apos a PRI, a concentracao intra-articular da gentamicina era de 47,58±49,21 µg/ml no G60 e 10,92±6,11 µg/ml no G250. Durante as 24 horas de colheita, a concentracao intra-articular de gentamicina permaneceu acima da concentracao inibitoria minima (CIM) (2 μg/ml) em ambos os grupos experimentais. No G60, as concentracoes de gentamicina no liquido sinovial atingiram a concentracao maxima e mantiveram-se 8 a 10 vezes mais elevadas que a CIM (Cmax: 16 a 20 μg/ml) durante 12 horas apos a PRI. Conclui-se que a PRI em membros, com 6,6 mg/kg de gentamicina diluida para o volume de 60 ml, promove concentracoes intra-articulares mais elevadas que o volume de 250 ml, permanecendo acima da CIM durante 24 horas e em concentracao maxima durante 12 horas