Simultaneous Assessment of Drug Interactions with Low- and High-Extraction Opioids

2003 ◽  
Vol 98 (4) ◽  
pp. 853-861 ◽  
Author(s):  
Andra E. Ibrahim ◽  
Jennifer Feldman ◽  
Aziz Karim ◽  
Evan D. Kharasch
Keyword(s):  
Plasma Concentration ◽  
Drug Interactions ◽  
Venous Blood ◽  
Extraction Ratio ◽  
Pharmacokinetic Parameters ◽  
Clinical Effects ◽  
Time Curve ◽  
Active Inhibitor ◽  
Perioperative Analgesia

Background Parecoxib is a parenteral cyclooxygenase-2 (COX-2) inhibitor intended for perioperative analgesia. It is an inactive prodrug hydrolyzed in vivo to the active inhibitor valdecoxib, a substrate for hepatic cytochrome P450 3A4 (CYP3A4); hence, a potential exists for metabolic interactions with other CYP3A substrates. This study determined the effects of parecoxib on the pharmacokinetics and pharmacodynamics of the CYP3A substrates fentanyl and alfentanil compared with the CYP3A inhibitor troleandomycin. Alfentanil is a low-extraction drug with a clearance that is highly susceptible to drug interactions; fentanyl is a high-extraction drug and, thus, is theoretically less vulnerable. We therefore also tested the hypothesis that the extraction ratio influences the consequence of altered hepatic metabolism of these opioids. Methods After Institutional Review Board-approved, written, informed consent was obtained, 12 22- to 40-yr-old healthy volunteers were enrolled in the study. The protocol was a randomized, double-blinded, balanced, placebo-controlled, three-session (placebo, parecoxib, or troleandomycin pretreatment) crossover. Subjects received both alfentanil (15 microg/kg) and fentanyl (5 microg/kg; 15-min intravenous infusion) 1 h after placebo, parecoxib (40 mg intravenously every 12 h), or troleandomycin (every 6 h). Study sessions were separated by 7 or more days. Opioid concentrations in venous blood were determined by liquid chromatography-mass spectrometry. Pharmacokinetic parameters were determined by noncompartmental analysis. Opioid effects were determined by pupillometry, respiratory rate, and Visual Analog Scale scores. Results There were no significant differences between the placebo and parecoxib treatments in alfentanil or fentanyl plasma concentration, maximum observed plasma concentration, area under the plasma time-concentration time curve, clearance, elimination half-life, or volume of distribution. However, disposition of alfentanil, and to a lesser extent fentanyl, was significantly altered by troleandomycin. Clearances were reduced to 12% (0.64 +/- 0.25 ml. kg-1. min-1) and 61% (9.35 +/- 3.07) of control (5.53 +/- 2.16 and 15.3 +/- 5.0) for alfentanil and fentanyl (P < 0.001). Pupil diameter versus time curves were similar between placebo and parecoxib treatments but were significantly different after troleandomycin. Conclusions Single-dose parecoxib does not alter fentanyl or alfentanil disposition or clinical effects and does not appear to cause significant CYP3A drug interactions. CYP3A inhibition decreases alfentanil clearance more than fentanyl clearance, confirming that the extraction ratio influences the consequence of altered hepatic drug metabolism. Modified cassette, or "cocktail," dosing is useful for assessing drug interactions in humans.

scholarly journals A Rapid and Sensitive UHPLC-MS/MS Method for Determination of 2, 3, 8-Trimethylellagic, a Potent Active Compound from Sanguisorba officinalis L., and Its Application in the Pharmacokinetic Study within Thrombocytopenia Rats

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Yuqing Wang ◽  
Jianming Wu ◽  
Yunxia Li ◽  
Jing Yang ◽  
Long Wang ◽  
...  
Keyword(s):  
Plasma Concentration ◽  
Maximum Concentration ◽  
High Performance ◽  
Internal Standard ◽  
Pharmacokinetic Parameters ◽  
Time Curve ◽  
Concentration Time ◽  
Relative Standard ◽  
Plasma Concentration Time Curve

To investigate the pharmacokinetics of 2, 3, 8-trimethylellagic (TMEA) in rats in vivo and determine the possible effects of the pathological conditions and compatibility, a rapid and sensitive ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method for quantitative determination was developed. TMEA and Artemetin (internal standard, IS) were separated on an Acquity Shim-pack GIST column with a total running time of 7 min using gradient elution at a flow rate of 0.3 mL/min. The intraday and interday relative standard deviations were <9.50%, and the relative error of accuracy was between −5.70% and 2.96%. The calibration curve of TMEA demonstrated good linearity with r2 = 0.9996, with the average recovery changing from 94.77% to 102.47% and the matrix effect from 93.16% to 100.15%. Compared with the normal group, the area under the plasma concentration-time curve from time 0 to the last time of quantifiable concentration (AUC(0 − t)), area under the plasma concentration-time curve from time 0 extrapolated to infinite time (AUC(0 − ∞)), and the maximum concentration (Cmax) of TMEA increased, whereas the time of maximum concentration (Tmax) and apparent clearance (CL/F) remarkably decreased in the TMEA group. With significantly reduced CL/F, AUC(0 − t), AUC(0 − ∞), and Cmax for TMEA were increased approximately one time after combining with 3, 7-Di-O-methylducheside A (DOMA). AUC(0 − t) and Cmax for TMEA in the 2, 3, 8-trimethylellagic-3, 8-dimethoxyellagic acid-2-oxyglucoside (TMEA-DMAG) group were significantly lower than that in the TMEA group with clearly prolonged Tmax and increased CL/F. These findings indicate that the changes in the pharmacokinetic parameters of TMEA may be caused by pathological and combination conditions.

scholarly journals Pharmacokinetic Profile of μSMIN Plus™, a new Micronized Diosmin Formulation, after Oral Administration in Rats

2015 ◽  
Vol 10 (9) ◽  
pp. 1934578X1501000 ◽  
Author(s):  
Rosario Russo ◽  
Angelo Mancinelli ◽  
Michele Ciccone ◽  
Fabio Terruzzi ◽  
Claudio Pisano ◽  
...  
Keyword(s):  
Oral Administration ◽  
Plasma Concentrations ◽  
Compartmental Analysis ◽  
Pharmacokinetic Profile ◽  
Pharmacokinetic Parameters ◽  
Maximum Plasma ◽  
Sprague Dawley ◽  
Time Curve ◽  
Maximum Plasma Drug Concentration

Diosmin is a naturally occurring flavonoid present in citrus fruits and other plants belonging to the Rutaceae family. It is used for the treatment of chronic venous insufficiency (CVI) for its pheblotonic and vaso-active properties, safety and tolerability as well. The aim of the current in vivo study was to investigate the pharmacokinetic profile of a branded micronized diosmin (μSMIN Plus™) compared with plain micronized diosmin in male Sprague-Dawley rats. After oral administration by gastric gavage, blood samples were collected via jugular vein catheters at regular time intervals from baseline up to 24 hours. Plasma concentrations were assessed by LC/MS. For each animal, the following pharmacokinetic parameters were calculated using a non-compartmental analysis: maximum plasma drug concentration (Cmax), time to reach Cmax (Tmax), area under the plasma concentration-time curve (AUC0-last), elimination half-life (t1/2), and relative oral bioavailability (%F). The results of the current study clearly showed an improvement in the pharmacokinetic parameters in animals treated with μSMIN Plus™ compared with animals treated with micronized diosmin. In particular, μSMIN Plus™ showed a 4-fold increased bioavailability compared with micronized diosmin. In conclusion, the results from the current study provided a preliminary pharmacokinetic profile for μSMIN Plus™, which may represent a new tool for CVI management.

Developing a new formulation of sodium phenylbutyrate

2012 ◽  
Vol 97 (12) ◽  
pp. 1081-1085 ◽  
Author(s):  
Nathalie Guffon ◽  
Yves Kibleur ◽  
William Copalu ◽  
C Tissen ◽  
Joerg Breitkreutz
Keyword(s):  
Plasma Concentration ◽  
Healthy Adult ◽  
Taste Perception ◽  
In Vitro Dissolution ◽  
Time Curve ◽  
New Formulation ◽  
Adult Volunteers ◽  
Sodium Phenylbutyrate

BackgroundSodium phenylbutyrate (NaPB) is used as a treatment for urea cycle disorders (UCD). However, the available, licensed granule form has an extremely bad taste, which can compromise compliance and metabolic control.ObjectivesA new, taste-masked, coated-granule formulation (Luc 01) under development was characterised for its in vitro taste characteristics, dissolution profiles and bioequivalence compared with the commercial product. Taste, safety and tolerability were also compared in healthy adult volunteers.ResultsThe in vitro taste profile of NaPB indicated a highly salty and bitter tasting molecule, but Luc 01 released NaPB only after a lag time of ∼10 s followed by a slow release over a few minutes. In contrast, the licensed granules released NaPB immediately. The pharmacokinetic study demonstrated the bioequivalence of a single 5 g dose of the two products in 13 healthy adult volunteers. No statistical difference was seen either for maximal plasma concentration (Cmax) or for area under the plasma concentration–time curve (AUC). CI for Cmax and AUC0–inf of NaPB were included in the bioequivalence range of 0.80–1.25. One withdrawal for vomiting and five reports of loss of taste perception (ageusia) were related to the licensed product. Acceptability, bitterness and saltiness assessed immediately after administration indicated a significant preference for Luc 01 (p<0.01), confirming the results of the taste prediction derived from in vitro measurements.ConclusionsIn vitro dissolution, in vitro and in vivo taste profiles support the view that the newly developed granules can be swallowed before release of the bitter active substance, thus avoiding stimulation of taste receptors. Moreover, Luc 01 was shown to be bioequivalent to the licensed product. The availability of a taste-masked form should improve compliance which is critical to the efficacy of NaPB treatment in patients with UCD.

scholarly journals Development of Level A In Vitro–Vivo Correlation for Electrosprayed Microspheres Containing Leuprolide: Physicochemical, Pharmacokinetic, and Pharmacodynamic Evaluation

Pharmaceutics ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 36
Author(s):  
Dong-Seok Lee ◽  
Dong Wook Kang ◽  
Go-Wun Choi ◽  
Han-Gon Choi ◽  
Hea-Young Cho
Keyword(s):  
Plasma Concentration ◽  
Prediction Error ◽  
Subcutaneous Administration ◽  
In Vitro Dissolution ◽  
Burst Release ◽  
Maximum Plasma ◽  
Time Curve ◽  
In Vivo Dissolution

This study optimized the preparation of electrosprayed microspheres containing leuprolide and developed an in vitro–in vivo correlation (IVIVC) model that enables mutual prediction between in vitro and in vivo dissolution. The pharmacokinetic (PK) and pharmacodynamic (PD) study of leuprolide was carried out in normal rats after subcutaneous administration of electrosprayed microspheres. The parameters of the IVIVC model were estimated by fitting the PK profile of Lucrin depot® to the release compartment of the IVIVC model, thus the in vivo dissolution was predicted from the in vitro dissolution. From this correlation, the PK profile of leuprolide was predicted from the results of in vivo dissolution. The IVIVC model was validated by estimating percent prediction error (%PE) values. Among prepared microspheres, an optimal formulation was selected using the IVIVC model. The maximum plasma concentration and the area under the plasma concentration–time curve from zero to infinity from the predicted PK profile were 4.01 ng/mL and 52.52 h·ng/mL, respectively, and from the observed PK profile were 4.14 ng/mL and 56.95 h·ng/mL, respectively. The percent prediction error values of all parameters did not exceed 15%, thus the IVIVC model satisfies the validation criteria of the Food and Drug Administration (FDA) guidance. The PK/PD evaluation suggests that the efficacy of OL5 is similar to Lucrin depot®, but the formulation was improved by reducing the initial burst release.

scholarly journals L-Dopa Pharmacokinetic Profile with Effervescent Melevodopa/Carbidopa versus Standard-Release Levodopa/Carbidopa Tablets in Parkinson’s Disease: A Randomised Study

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Fabrizio Stocchi ◽  
Laura Vacca ◽  
Paola Grassini ◽  
Stephen Pawsey ◽  
Holly Whale ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Plasma Concentration ◽  
Pharmacokinetic Profile ◽  
Pharmacokinetic Parameters ◽  
Maximum Plasma ◽  
Double Blind ◽  
Time Curve ◽  
Randomised Study ◽  
Effervescent Tablet

Objectives.To characterize the pharmacokinetic profile of levodopa (L-dopa) and carbidopa after repeated doses of the effervescent tablet of melevodopa/carbidopa (V1512; Sirio) compared with standard-release L-dopa/carbidopa in patients with fluctuating Parkinson’s disease. Few studies assessed the pharmacokinetics of carbidopa to date.Methods.This was a single-centre, randomized, double-blind, double-dummy, two-period crossover study. Patients received V1512 (melevodopa 100 mg/carbidopa 25 mg) or L-dopa 100 mg/carbidopa 25 mg, 7 doses over 24 hours (Cohort 1), 4 doses over 12 hours (Cohort 2), or 2 doses over 12 hours in combination with entacapone 200 mg (Cohort 3). Pharmacokinetic parameters included area under the plasma-concentration time curve (AUC), maximum plasma concentration (Cmax), and time toCmax(tmax).Results.Twenty-five patients received at least one dose of study medication. L-dopa absorption tended to be quicker and pharmacokinetic parameters less variable after V1512 versus L-dopa/carbidopa, both over time and between patients. Accumulation of L-dopa in plasma was less noticeable with V1512. Carbidopa exposure and interpatient variability was lower when V1512 or L-dopa/carbidopa was given in combination with entacapone. Both treatments were well tolerated.Conclusions.V1512 provides a more reliable L-dopa pharmacokinetic profile versus standard-release L-dopa/carbidopa, with less drug accumulation and less variability. This trial is registered with ClinicalTrials.govNCT00491998.

Plasma Inorganic Fluoride Concentrations after Sevoflurane Anesthesia in Children

1996 ◽  
Vol 84 (2) ◽  
pp. 348-353. ◽  
Author(s):  
M. F. Levine ◽  
J. Sarner ◽  
J. Lerman ◽  
P. Davis ◽  
N. Sikich ◽  
...  
Keyword(s):  
Plasma Concentration ◽  
Elective Surgery ◽  
Plasma Concentrations ◽  
Sevoflurane Anesthesia ◽  
Inorganic Fluoride ◽  
Time Curve ◽  
Plasma Urea ◽  
The Mean ◽  
Group 2

Background Sevoflurane is degraded in vivo in adults yielding plasma concentrations of inorganic fluoride [F-] that, in some patients, approach or exceed the 50- micron theoretical threshold for nephrotoxicity. To determine whether the plasma concentration of inorganic fluoride [F-] after 1-5 MAC x h sevoflurane approaches a similar concentration in children, the following study in 120 children scheduled for elective surgery was undertaken. Methods Children were randomly assigned to one of three treatment groups before induction of anesthesia: group 1 received sevoflurane in air/oxygen 30% (n = 40), group 2 received sevoflurane in 70% N2O/30% O2 (n = 40), and group 3 received halothane in 70% N2O/30% O2 (n = 40). Mapleson D or F circuits with fresh gas flows between 3 and 61/min were used Whole blood was collected at induction and termination of anesthesia and at 1, 4, 6, 12, and 18 or 24 h postoperatively for determination of the [F-]. Plasma urea and creatinine concentrations were determined at induction of anesthesia and 18 or 24 h postoperatively. Results The mean (+/- SD) duration of sevoflurane anesthesia, 2.7 +/- 1.6 MAC x h (range 1.1-8.9 MAC x h), was similar to that of halothane, 2.5 +/- 1.1 MAC x h. The peak [F-] after sevoflurane was recorded at 1 h after termination of the anesthetic in all but three children (whose peak values were recorded between 4 and 6 h postanesthesia). The mean peak [F-] after sevoflurane was 15.8 +/- 4.6 microns. The [F-] decreased to &lt;6.2 microns b 24 h postanesthesia. Both the peak [F-] (r2 = 0.50) and the area under the plasma concentration of inorganic fluoride-time curve (r2 = 0.57) increased in parallel with the MAC x h of sevoflurane. The peak [F-] after halothane, 2.0 +/- 1.2 microns, was significantly less than that after sevoflurane (P&lt;0.00012) and did not correlate with the duration of halothane anesthesia (MAC x h; r2 = 0.007). Plasma urea concentrations decreased 24 h after surgery compared with preoperative values for both anesthetics (P&lt;0.01), whereas plasma creatinine concentrations did not change significantly with either anesthetic. Conclusions It was concluded that, during the 24 h after 2.7 +/- 1.6 MAC x h sevoflurane, the peak recorded [F-] is low (15.8 microns), F- is eliminated rapidly, and children are unlikely to be at risk of nephrotoxicity from high [F-].

scholarly journals Effect of CYP3A4 metabolism on sex differences in the pharmacokinetics and pharmacodynamics of zolpidem

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Seonghae Yoon ◽  
Seongmee Jeong ◽  
Eben Jung ◽  
Ki Soon Kim ◽  
Inseung Jeon ◽  
...  
Keyword(s):  
Adverse Event ◽  
Plasma Concentration ◽  
Compartmental Analysis ◽  
Pharmacokinetic Parameters ◽  
Maximum Plasma ◽  
Digit Symbol Substitution Test ◽  
Cyp3a4 Activity ◽  
Post Dose ◽  
Time Curve ◽  
Apparent Clearance

AbstractTo investigate pharmacokinetic and pharmacodynamic differences of zolpidem between males and females and their causes, including CYP3A4 activity. A single oral dose of zolpidem (10 mg) was administered to 15 male and 15 female healthy subjects. Blood samples were collected up to 12 h post-dose to determine plasma zolpidem concentrations. Pharmacokinetic parameters were obtained using non-compartmental analysis. Digit symbol substitution test, choice reaction time, and visual analog scale of sleepiness were used to evaluate pharmacodynamics. We measured CYP3A4 activity using 4β-hydroxycholesterol, an endogenous metabolite. Mean maximum plasma concentration and area under the plasma concentration–time curve were higher for females than for males (9.9% and 32.5%, respectively); other pharmacokinetic parameters showed no significant differences. Pharmacodynamic scores for females showed delayed recovery compared with that for males. CYP3A4 activity was higher in females than in males (p = 0.030). There was no serious adverse event, and adverse event incidence was not different between the sexes. Zolpidem exposure was about 30% higher in females than in males. Delayed pharmacodynamic score recovery in females could be related to higher zolpidem concentrations. Although apparent clearance was lower in females, systemic clearance might not be the cause of the different exposures to zolpidem.

scholarly journals Interactions of 172 plant extracts with human organic anion transporter 1 (SLC22A6) and 3 (SLC22A8): a study on herb-drug interactions

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e3333 ◽  
Author(s):  
Hang Lu ◽  
Zhiqiang Lu ◽  
Xue Li ◽  
Gentao Li ◽  
Yilin Qiao ◽  
...  
Keyword(s):  
Drug Interactions ◽  
Plant Extracts ◽  
Organic Anion ◽  
Organic Anion Transporter ◽  
Hek293 Cells ◽  
Pharmacokinetic Parameters ◽  
Renal Elimination ◽  
Juncus Effusus ◽  
Anion Transporter

BackgroundHerb-drug interactions (HDIs) resulting from concomitant use of herbal products with clinical drugs may cause adverse reactions. Organic anion transporter 1 (OAT1) and 3 (OAT3) are highly expressed in the kidney and play a key role in the renal elimination of substrate drugs. So far, little is known about the herbal extracts that could modulate OAT1 and OAT3 activities.MethodsHEK293 cells stably expressing human OAT1 (HEK-OAT1) and OAT3 (HEK-OAT3) were established and characterized. One hundred seventy-two extracts from 37 medicinal and economic plants were prepared. An initial concentration of 5 µg/ml for each extract was used to evaluate their effects on 6-carboxylfluorescein (6-CF) uptake in HEK-OAT1 and HEK-OAT3 cells. Concentration-dependent inhibition studies were conducted for those extracts with more than 50% inhibition to OAT1 and OAT3. The extract ofJuncus effusus, a well-known traditional Chinese medicine, was assessed for its effect on thein vivopharmacokinetic parameters of furosemide, a diuretic drug which is a known substrate of both OAT1 and OAT3.ResultsMore than 30% of the plant extracts at the concentration of 5 µg/ml showed strong inhibitory effect on the 6-CF uptake mediated by OAT1 (61 extracts) and OAT3 (55 extracts). Among them, three extracts for OAT1 and fourteen extracts for OAT3 were identified as strong inhibitors with IC50values being <5 µg/ml.Juncus effususshowed a strong inhibition to OAT3in vitro, and markedly altered thein vivopharmacokinetic parameters of furosemide in rats.ConclusionThe present study identified the potential interactions of medicinal and economic plants with human OAT1 and OAT3, which is helpful to predict and to avoid potential OAT1- and OAT3-mediated HDIs.

scholarly journals Determination of myrislignan levels in BALB/c mouse plasma by LC-MS/MS and a comparison of its pharmacokinetics after oral and intraperitoneal administration

2021 ◽  
Vol 17 (1) ◽  
Author(s):  
Jili Zhang ◽  
Hongfei Si ◽  
Jichao Sun ◽  
Kun Lv ◽  
Biqing Yan ◽  
...  
Keyword(s):  
Formic Acid ◽  
Intraperitoneal Administration ◽  
Internal Standard ◽  
Pharmacokinetic Parameters ◽  
Clinical Effects ◽  
Limit Of Quantification ◽  
Mouse Plasma ◽  
Relative Standard ◽  
Liquid Chromatography Tandem Mass

Abstract Background Myrislignan is a natural product from Myristica sp. with diverse pharmacological activities. Recently, the anti-Toxoplasma gondii (T. gondii) activity of myrislignan has been proposed, and in vivo studies of its pharmacokinetics in BALB/c mice are necessary to further evaluate the clinical effects of myrislignan. Results In this study, a sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated to quantify myrislignan levels in mouse plasma using dehydrodiisoeugenol as an internal standard (IS) in positive ion mode. Chromatographic separation of the analytes was achieved using an ACE Ultracore Super C18 analytical column (2.5 μm, 2.1 × 50 mm) at 30 °C. A gradient mobile phase consisting of water (0.1 % formic acid) and acetonitrile (0.1 % formic acid) was delivered at a flow rate of 0.4 mL/min. Myrislignan and the IS eluted at 1.42 and 1.71 min, respectively. A good excellent linear response across the concentration range of 1-1000 ng/mL was achieved (r2 = 0.9973). The lower limit of quantification (LLOQ) was 1 ng/mL, and the inter- and intra-day accuracy and precision of the method showed relative standard deviations (RSDs) less than 10 %. The method was applied to examine the pharmacokinetics of myrislignan in mouse plasma following a single oral administration of 200 mg/kg or intraperitoneal administration of 50 mg/kg myrislignan, and the bioavailability (F) of orally administered myrislignan was only 1.97 % of the bioavailability of intraperitoneally administered myrislignan. Conclusions A rapid and sensitive LC-MS/MS method has been was developed, validated and successfully used to determine myrislignan levels in mice after oral or intraperitoneal administration. This study is the first to report the pharmacokinetic parameters of myrislignan in mice and to compare its pharmacokinetics after oral and intraperitoneal administration, which will be useful for further research on the administration of myrislignan in animals and humans.

scholarly journals Concentrations and pharmacokinetic parameters of MRI and SPECT hepatobiliary agents in rat liver compartments

2021 ◽  
Vol 5 (1) ◽  
Author(s):  
Catherine M. Pastor ◽  
Florian Joly ◽  
Valérie Vilgrain ◽  
Philippe Millet
Keyword(s):  
Ex Vivo ◽  
Volume Ratio ◽  
Gadobenate Dimeglumine ◽  
Extraction Ratio ◽  
Pharmacokinetic Parameters ◽  
Bile Canaliculi ◽  
Canalicular Transporters ◽  
Rat Livers ◽  
Hepatobiliary Agents

Abstract Background In hepatobiliary imaging, systems detect the total amount of agents originating from extracellular space, bile canaliculi, and hepatocytes. They add in situ concentration of each compartment corrected by its respective volume ratio to provide liver concentrations. In vivo contribution of each compartment to liver concentration is inaccessible. Our aim was to quantify the compartmental distribution of two hepatobiliary agents in an ex vivo model and determine how their liver extraction ratios and cholestasis (livers lacking canalicular transporters) might modify it. Methods We perfused labelled gadobenate dimeglumine (Bopta, 200 μM, 7% liver extraction ratio) and mebrofenin (Meb, 64 μM, 94% liver extraction ratio) in normal (n = 18) and cholestatic (n = 6) rat livers. We quantified liver concentrations with a gamma counter placed over livers. Concentrations in hepatocytes and bile canaliculi were calculated. Mann-Whitney and Kruskal-Wallis tests were used. Results Hepatocyte concentrations were 2,043 ± 333 μM (Meb) versus 360 ± 69 μM (Bopta, p < 0.001). Meb extracellular concentrations did not contribute to liver concentrations (1.3 ± 0.3%). The contribution of Bopta extracellular concentration was 12.4 ± 1.9% (p < 0.001 versus Meb). Contribution of canaliculi was similar for both agents (16%). Cholestatic livers had no Bopta in canaliculi but their hepatocyte concentrations increased in comparison to normal livers. Conclusion Hepatocyte concentrations are correlated to liver extraction ratios of hepatobiliary agents. When Bopta is not present in canaliculi of cholestatic livers, hepatocyte concentrations increase in comparison to normal livers. This new understanding extends the interpretation of clinical liver images.

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