Arimori K, Nakano M
Department of Pharmacy, Kumamoto University Hospital, Japan.
J Pharm Pharmacol. 1988 Feb;40(2):101-5. doi: 10.1111/j.2042-7158.1988.tb05190.x.
The elimination half-life of theophylline in serum after intravenous (i.v.) administration of aminophylline increased with increase in dose. Exsorption of theophylline from blood to the gastrointestinal tract was investigated after i.v. administration of aminophylline (10-50 mg kg-1) to rats by the in-situ single-pass perfusion technique. The exsorption rate of theophylline into the intestinal lumen also increased with increase in dose. When the dose of aminophylline was increased five-fold from 10 to 50 mg kg-1, the amount of theophylline exsorbed in 120 min was proportionally increased from 450 to 2300 micrograms. The average extent of theophylline exsorbed into the intestinal lumen was 12-15% after doses from 10-50 mg kg-1, while the extent of the drug excreted into the bile varied from 0.17-0.30% after doses from 10-50 mg kg-1. However, intestinal and biliary clearance of theophylline did not change significantly in the range 10 to 50 mg kg-1. Oral administration of multiple doses of activated charcoal reduced the serum theophylline levels after i.v. administration of aminophylline (50 mg kg-1) to rats. The serum half-life and the area under the serum concentration-time curve of theophylline were decreased to 52 and 50% by the charcoal treatment, respectively, while the total body clearance of the drug was increased to 188% compared with the corresponding control experiments. The volume of distribution was not significantly different between treated and control rats.(ABSTRACT TRUNCATED AT 250 WORDS)
静脉注射氨茶碱后，血清中茶碱的消除半衰期随剂量增加而延长。采用原位单通道灌注技术，对大鼠静脉注射氨茶碱（10 - 50 mg/kg）后，研究了茶碱从血液到胃肠道的外排情况。茶碱向肠腔的外排速率也随剂量增加而增加。当氨茶碱剂量从10 mg/kg增加5倍至50 mg/kg时，120分钟内茶碱的外排量从450微克按比例增加至2300微克。剂量为10 - 50 mg/kg时，茶碱向肠腔的平均外排程度为12 - 15%，而剂量为10 - 50 mg/kg时，药物排入胆汁的程度为0.17 - 0.30%。然而，在10至50 mg/kg范围内，茶碱的肠道和胆汁清除率无显著变化。对大鼠静脉注射氨茶碱（50 mg/kg）后，多次口服活性炭可降低血清茶碱水平。与相应的对照实验相比，活性炭处理使茶碱的血清半衰期和血清浓度-时间曲线下面积分别降至52%和50%，而药物的全身清除率增加至188%。处理组和对照组大鼠的分布容积无显著差异。（摘要截短于250字）
