Weijkamp K, Faghihi S M, Nijmeijer S M, Witkamp R F, van Miert A S
Department of Veterinary Basic Sciences, Utrecht University, The Netherlands.
Vet Q. 1994 Mar;16(1):33-7. doi: 10.1080/01652176.1994.9694413.
To get a better insight into the oral bioavailability of sulphonamides in ruminants, sulphamethoxydiazine (pKa 7.0), sulphathiazole (pKa 7.2), and sulphamoxole (pKa 7.4) were administered to dwarf goats (n = 5). The drugs were given at 2-week intervals by the intravenous or intraruminal route at a dose of 100 mg per kg body weight. After IV injection, the mean half-life (t1/2 beta in h +/- SEM) was 0.80 +/- 0.10 h, 2.35 +/- 0.38 h, and 3.36 +/- 1.25 h, for sulphathiazole, sulphamoxole, and sulphamethoxydiazine, respectively and the mean distribution volume (Vd beta) was 0.23 +/- 0.05 l/kg, 0.23 +/- 0.04 l/kg, and 0.33 +/- 0.02 l/kg. After intraruminal administration, the mean bioavailability varied from 86.0 +/- 11.8% for sulphamethoxydiazine to 46.6 +/- 4.3% for sulphamoxole, and 52.6 +/- 7.2% for sulphathiazole. The elimination half-life was significantly prolonged, probably due to a low rate of drug absorption from the gastrointestinal tract. In contrast to chloramphenicol, the sulphonamides studied were stable when incubated in rumen fluid at 39 degrees C.
为了更深入了解磺胺类药物在反刍动物中的口服生物利用度，给5只矮山羊施用了磺胺甲氧基嘧啶（pKa 7.0）、磺胺噻唑（pKa 7.2）和磺胺恶唑（pKa 7.4）。每隔两周通过静脉内或瘤胃内途径以每千克体重100毫克的剂量给药。静脉注射后，磺胺噻唑、磺胺恶唑和磺胺甲氧基嘧啶的平均半衰期（t1/2β，单位为小时，h±标准误，SEM）分别为0.80±0.10小时、2.35±0.38小时和3.36±1.25小时，平均分布容积（Vdβ）分别为0.23±0.05升/千克、0.23±0.04升/千克和0.33±0.02升/千克。瘤胃内给药后，磺胺甲氧基嘧啶的平均生物利用度为86.0±11.8%，磺胺恶唑为46.6±4.3%，磺胺噻唑为52.6±7.2%。消除半衰期显著延长，可能是由于药物从胃肠道的吸收速率较低。与氯霉素不同，所研究的磺胺类药物在39摄氏度的瘤胃液中孵育时是稳定的。
