Pypendop B H, Ilkiw J E, Shilo-Benjamini Y
Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California, Davis, CA, USA.
J Vet Pharmacol Ther. 2014 Jun;37(3):295-300. doi: 10.1111/jvp.12090. Epub 2013 Nov 18.
Buccal administration of buprenorphine is commonly used to treat pain in cats. It has been argued that absorption of buprenorphine through the buccal mucosa is high, in part due to its pKa of 8.24. Morphine, methadone, hydromorphone, and oxymorphone have a pKa between 8 and 9. This study characterized the bioavailability of these drugs following buccal administration to cats. Six healthy adult female spayed cats were used. Buccal pH was measured prior to drug administration. Morphine sulfate, 0.2 mg/kg IV or 0.5 mg/kg buccal; methadone hydrochloride, 0.3 mg/kg IV or 0.75 mg/kg buccal; hydromorphone hydrochloride, 0.1 mg/kg IV or 0.25 mg/kg buccal; or oxymorphone hydrochloride, 0.1 mg/kg IV or 0.25 mg/kg buccal were administered. All cats received all treatments. Arterial blood was sampled immediately prior to drug administration and at various times up to 8 h thereafter. Bioavailability was calculated as the ratio of the area under the time-concentration curve following buccal administration to that following IV administration, each indexed to the administered dose. Mean ± SE (range) bioavailability was 36.6 ± 5.2 (12.7-49.5), 44.2 ± 7.9 (18.7-70.5), 22.4 ± 6.9 (6.4-43.4), and 18.8 ± 2.0 (12.9-23.5)% for buccal administration of morphine, methadone, hydromorphone, and oxymorphone, respectively. Bioavailability of methadone was significantly higher than that of oxymorphone.
丁丙诺啡经颊给药常用于治疗猫的疼痛。有人认为，丁丙诺啡通过颊黏膜的吸收很高，部分原因是其pKa为8.24。吗啡、美沙酮、氢吗啡酮和羟吗啡酮的pKa在8至9之间。本研究对这些药物经颊给药给猫后的生物利用度进行了表征。使用了6只健康成年雌性去势猫。在给药前测量颊部pH值。分别静脉注射硫酸吗啡0.2mg/kg或经颊给药0.5mg/kg；静脉注射盐酸美沙酮0.3mg/kg或经颊给药0.75mg/kg；静脉注射盐酸氢吗啡酮0.1mg/kg或经颊给药0.25mg/kg；或静脉注射盐酸羟吗啡酮0.1mg/kg或经颊给药0.25mg/kg。所有猫都接受了所有治疗。在给药前即刻以及给药后长达8小时的不同时间采集动脉血样。生物利用度计算为经颊给药后时间-浓度曲线下面积与静脉给药后时间-浓度曲线下面积之比，每个都以给药剂量为指标。吗啡、美沙酮、氢吗啡酮和羟吗啡酮经颊给药的平均±标准误（范围）生物利用度分别为36.6±5.2（12.7 - 49.5）、44.2±7.9（18.7 - 70.5）、22.4±6.9（6.4 - 43.4）和18.8±2.0（12.9 - 23.5）%。美沙酮的生物利用度显著高于羟吗啡酮。
