ABSTRACT
The reactive metabolites of diclofenac (DF) such as 1-O-acyl glucuronide (DF-Glu) are hypothesized to result in idiosyncratic hepatotoxicity. However, it is unclear whether inflammation affects the hepatic disposition of DF and its metabolites. To clarify the alterations in the disposition of DF and its metabolites in inflammatory conditions, we performed in situ perfused rat liver experiments. Using adjuvant arthritis rats as a model of inflammation, the elimination of DF, 4'-hydroxydiclofenac, and DF-Glu from the perfusate was observed to be delayed in comparison with the control. Parameter sensitivity analysis for hepatic DF disposition revealed that the area under the plasma concentration-time curve (AUC) and the maximum concentration (Cmax) of DF-Glu in the liver markedly increased along with a decrease in intrinsic excretion clearance of DF-Glu (CLint,bile,Glu) and an increase in intrinsic glucuronidation clearance (CLint,Glu) of DF-Glu. It is possible that the elimination of DF-Glu from the perfusate in adjuvant arthritis rats was delayed via reduction of biliary excretion of DF-Glu.
Subject(s)
Arthritis, Experimental/metabolism , Diclofenac/metabolism , Liver/metabolism , Perfusion/methods , Animals , Anti-Inflammatory Agents, Non-Steroidal/metabolism , Anti-Inflammatory Agents, Non-Steroidal/therapeutic use , Arthritis, Experimental/drug therapy , Diclofenac/pharmacology , Diclofenac/therapeutic use , Female , Liver/drug effects , Protein Binding/drug effects , Protein Binding/physiology , Rats , Rats, Sprague-DawleyABSTRACT
1. The effects of adjuvant-induced arthritis (AA) on the stereoselective hepatic disposition and chiral inversion of "profens" have scarcely been investigated. Ibuprofen (IB) undergoes unidirectional chiral inversion from R-IB to S-IB and is metabolized to IB-glucuronide (IB-Glu). 2. We used an in situ perfused rat liver system to clarify the effects of inflammation on the metabolic activities and chiral inversion of IB without protein binding. 3. After dosing of R-IB, AA had minimal effect on the elimination of R-IB from the perfusate. Larger amounts of S-IB-Glu than R-IB-Glu were observed in the bile at the dose of 2.4 and 4.8 µmol. However, after dosing of S-IB, the elimination of S-IB from the perfusate in AA rats was delayed, indicating a significant decrease in the hepatic clearance in AA rats. The cumulative biliary excretion of S-IB-Glu in AA rats was promoted after dosing with S-IB. There was little difference between the chiral inversion ratios of the control and AA rats. 4. The present study demonstrated that AA results in the delayed elimination of S-IB, the active form, without changes to the chiral inversion ratio. Thus, further attention to the altered stereoselective pharmacokinetics of IB during inflammation is required.
Subject(s)
Anti-Inflammatory Agents, Non-Steroidal/metabolism , Ibuprofen/metabolism , Liver/metabolism , Animals , Arthritis, Experimental , Male , Rats , StereoisomerismABSTRACT
An in situ perfused rat liver system is useful for studying the hepatic disposition of drugs and their metabolites. However, the effects of the perfusion conditions on drug disposition are unclear. We examined the effects of conditions such as flow rate (13 or 26 mL/min) and bile acid on disposition of diclofenac (DF) as a model drug and DF metabolites [diclofenac-1-O-acyl glucuronide (DF-Glu) or 4'-hydroxydiclofenac (DF-4'OH)] in the absence of albumin. DF, DF-Glu, and DF-4'OH concentrations in the perfusate and cumulative amounts of DF-Glu excreted in bile were measured using high-performance liquid chromatography methods. DF in the perfusate was rapidly eliminated as the perfusate flow rate increased. The area under the plasma concentration-time curve from 0 to 60 min (AUC0-60) for DF-Glu and DF-4'OH in a perfusate containing bile acid was lower at a flow rate of 26 and 13 mL/min, respectively. The bile flow rate at 26 mL/min with 24 µM of bile acid in the perfusate was significantly higher (ca. 3.5 times) compared with that at 13 mL/min without bile acid. Cumulative biliary DF-Glu excretion was also dramatically affected by the flow rate and addition of bile acid. This study indicated that the flow rate and bile acid in the perfused rat liver were key factors for bile flow rate and DF, DF-Glu, and DF-4'OH disposition in the absence of albumin.
Subject(s)
Diclofenac/metabolism , Liver/metabolism , Animals , Bile/metabolism , Bile Acids and Salts , Diclofenac/analogs & derivatives , Female , Glucuronides/metabolism , Perfusion/methods , Rats , Rats, Sprague-DawleyABSTRACT
In this study, a real-time reverse transcription-polymerase chain reaction was used to determine the effects of adjuvant-induced arthritis (AA) on the amounts of mRNA of 12 types of rat ATP-binding cassette (ABC) and solute carrier (SLC) transporters in the liver and small intestine, 7 (D7) and 21 days (D21) after the injection of adjuvant. There were no significant differences in mRNA levels of ABC and SLC transporters between the livers of AA and control rats on D7, except in the case of Mdr1a. However, levels of Mdr1a, Mrp2 and Oatp SLC transporters were significantly lower in AA than in the control livers on D21. In contrast, the mRNA levels of several ABC and SLC transporters, especially Mrp2, Bcrp, LAT2 and Oatp1a5, were significantly lower in the small intestines of AA rats compared with the controls on D7, though there were no significant differences by D21. The time-dependent alterations in mRNA levels of the pregnane X receptor, but not the constitutive androstane receptor, in the liver and intestine were similar to the changes in mRNA levels of most transporters examined. The present study showed that AA was associated with reduced mRNA expression of several ABC and SLC transporters in the liver and small intestine, but that the time courses of the effects of AA on mRNA expression differed between the liver and small intestine. These results raise the possibility of a functional change of the transporters of liver and intestine in AA rats.
