The effect of pretreatment (i.e., oral administration of loxoprofen for 3 consecutive days followed by a 7-day washout) on the pharmacokinetics and metabolism of the drug was studied in humans. In a control study, a Loxonin tablet (60 mg as loxoprofen anhydrous) was administered orally to 6 healthy
Comparison of pharmacokinetics of loxoprofen and its active metabolites after an intravenous, intramuscular, and oral administration of loxoprofen in rats: Evidence for extrahepatic metabolism
โ Scribed by Tae-Sung Koo; Dae-Hyun Kim; Sung-Hoon Ahn; Kang-Pil Kim; In-Wha Kim; Seung-Yong Seo; Young-Ger Suh; Dae-Duk Kim; Chang-Koo Shim; Suk-Jae Chung
- Publisher
- John Wiley and Sons
- Year
- 2005
- Tongue
- English
- Weight
- 146 KB
- Volume
- 94
- Category
- Article
- ISSN
- 0022-3549
No coin nor oath required. For personal study only.
โฆ Synopsis
The objective of this study was to characterize the extent of the formation of the active (trans-alcohol form) and inactive (cis-alcohol) metabolites of loxoprofen and to compare the kinetics after its intragastric, intravenous, and intramuscular administrations in rats. After intravenous administration of the drug at doses of 5-20 mg/kg, the clearance and the volume of distribution for loxoprofen, and the ratios of the AUC for the metabolites to the parent drug were not statistically different with the dosage; the formation clearances were 1.08 and 0.87 mL/min/kg for the active and its isomeric metabolite, respectively. After the intragastric, intravenous, or intramuscular administration, AUC for loxoprofen and the metabolites at a dose of 10 mg/kg were not statistically different for the different routes of administration. The formation of the metabolites with the concomitant loss of loxoprofen was found in incubations with liver homogenates and blood but not with a muscle homogenate or plasma, indicating that the conversion of loxoprofen to the metabolites may occur both in the liver and extraheptic tissue(s). Thus, approximately 22% of the loxoprofen may have been converted to the active metabolite in the liver and the extraheptic tissue(s) and the pharmacokinetics of the active metabolite was independent of the route of administration.
๐ SIMILAR VOLUMES
It was reported that ipriflavone was primarily metabolized via hepatic CYP1A1/2 and 2C11 in rats. In the present study, the expression of CYP1A2 and 2C11 decreased in the liver, but increased in the intestine in rats pretreated with E. coli lipopolysaccharide (ECLPS; an animal model of inflammation)