scholarly journals A study of intestinal absorption of bicyclol in rats: active efflux transport and metabolism as causes of its poor bioavailability

2008 ◽  
Vol 11 (3) ◽  
pp. 97 ◽  
Author(s):  
Wei Tan ◽  
Hui Chen ◽  
Jinping Hu ◽  
Yan Li
Keyword(s):  
Cell Monolayer ◽  
Intestinal Perfusion ◽  
Efflux Transport ◽  
Glycoprotein P ◽  
Active Efflux ◽  
The Poor ◽  
P Glycoprotein ◽  
Respective Contribution ◽  
Monolayer Model

Purpose.To determine the possible mechanism of poor bioavailability of bicyclol, and clarify the respective contribution of P- glycoprotein (P-gp) and Cytochrome 3A (CYP3A). Methods. Rat in situ single-pass intestinal perfusion and Caco-2 cell monolayer model with selective inhibitors of CYP3A and P-gp were employed. Results. In rat intestinal perfusion, bicyclol (50µM) appearance in mesenteric blood (Pblood) was increased 3, 12, 16-fold by addition of inhibitors of P-gp (LSN335984), CYP3A ( troleandomycin, TAO) or P-gp and CYP3A (Cyclosporin A, CsA), respectively, whereas permeability of midazolam (CYP3A substrate only) was unchanged by LSN335984 and increased 5 and 1-fold by TAO and CsA. In addition, the metabolized fraction of bicyclol was decreased by 9%, 33%, 36% with inhibitor of P-gp, CYP3A, or P-gp and CYP3A. Moreover, the cumulative amount of bicyclol in mesenteric blood was increased at concentration range 10-100µM of bicyclol in perfusate. The ER (Pappba/Pappab) value of bicyclol in Caco-2 monolayer was significantly deceased by LSN335984 and CsA. Conclusion. The poor bioavailability of bicyclol was mostly due to the P-gp mediated efflux and metabolism by CYP3A in intestine, while CYP3A was believed to make more contribution than P-gp.

scholarly journals Investigation of the Functional Role of P-Glycoprotein in Limiting the Oral Bioavailability of Lumefantrine

2013 ◽  
Vol 58 (1) ◽  
pp. 489-494 ◽  
Author(s):  
Wahajuddin ◽  
Kanumuri S. R. Raju ◽  
Sheelendra P. Singh ◽  
Isha Taneja
Keyword(s):  
Intestinal Absorption ◽  
Oral Absorption ◽  
Stability Study ◽  
Cytochrome P450 3A ◽  
Glycoprotein P ◽  
Active Efflux ◽  
P Glycoprotein

ABSTRACTIn the quest to explore the reason for the low and variable bioavailability of lumefantrine, we investigated the possible role of P-glycoprotein (P-gp) in lumefantrine intestinal absorption. Anin situsingle-pass intestinal perfusion study in rats with the P-gp inhibitor verapamil or quinidine and an ATPase assay with human P-gp membranes indicated that lumefantrine is a substrate of P-gp which limits its intestinal absorption. To confirm these findings, anin vivopharmacokinetic study was performed in rats. The oral administration of verapamil (10 mg/kg of body weight) along with lumefantrine caused a significant increase in its bioavailability with a concomitant decrease in clearance. The increase in bioavailability of lumefantrine could be due to inhibition of P-gp and/or cytochrome P450 3A in the intestine/liver by verapamil. However, in a rat intestinal microsomal stability study, lumefantrine was found to be resistant to oxidative metabolism. Further, anin situpermeation study clearly showed a significant role of P-gp in limiting the oral absorption of lumefantrine. Thus, the increase in lumefantrine bioavailability with verapamil is attributed in part to the P-gp-inhibitory ability of verapamil. In conclusion, lumefantrine is a substrate of P-gp, and active efflux by P-gp across the intestine partly contributed to the low/variable bioavailability of lumefantrine.

scholarly journals Expression and Localization of P-glycoprotein in Human Heart

2002 ◽  
Vol 50 (10) ◽  
pp. 1351-1356 ◽  
Author(s):  
Konrad Meissner ◽  
Bernhard Sperker ◽  
Christiane Karsten ◽  
Henriette Meyer zu Schwabedissen ◽  
Ute Seeland ◽  
...  
Keyword(s):  
Dilated Cardiomyopathy ◽  
Human Heart ◽  
Cardiac Glycosides ◽  
Transport Proteins ◽  
Rt Pcr ◽  
Glycoprotein P ◽  
Variable Expression ◽  
P Glycoprotein ◽  
The Individual

ABC-type transport proteins, such as P-glycoprotein (P-gp), modify intracellular concentrations of many substrate compounds. They serve as functional barriers against entry of xenobiotics (e.g., in the gut or the blood-brain barrier) or contribute to drug excretion. Expression of transport proteins in the heart could be an important factor modifying cardiac concentrations of drugs known to be transported by P-gp (e.g., β-blockers, cardiac glycosides, doxorubicin). We therefore investigated the expression and localization of P-gp in human heart. Samples from 15 human hearts (left ventricle; five non-failing, five dilated cardiomyopathy, and five ischemic cardiomyopathy) were analyzed for expression of P-gp using real-time RT-PCR, immunohistochemistry, and in situ hybridization. Immunohistochemistry revealed expression of P-gp in endothelium of both arterioles and capillaries of all heart samples. Although P-gp mRNA was detected in all samples, its expression level was significantly reduced in patients with dilated cardiomyopathy. We describe variable expression of P-gp in human heart and its localization in the endothelial wall. Thus, intracardiac concentrations of various compounds may be modified, depending on the individual P-gp level.

scholarly journals INFLUENCE OF P-GLYCOPROTEIN AND CYTOCHROME ISOENZYME-P3A4 ON BIOAVAILABILITY OF ANTICANCER DRUGS WITH CURCUMIN BY IN SITU INTESTINAL PERFUSION IN MALE WISTAR RATS

2019 ◽  
pp. 184-187
Author(s):  
MANOJ KANNA NALLA ◽  
SHANKARAIAH PULIGILLA
Keyword(s):  
Venous Blood ◽  
Hepatic Metabolism ◽  
Intestinal Perfusion ◽  
Hepatic Veins ◽  
Perfusion Technique ◽  
Flow Rates ◽  
P Glycoprotein ◽  
Drug Concentrations ◽  
In Situ Intestinal Perfusion

Objectives: An orally administered anticancer drug has been poor drug absorption; drug resistance and metabolism, which alters the bioavailability of drugs. An in situ intestine perfusion technique is developing under the different perfusion rates in the presence of drug inducers and inhibitors of cytochrome isoenzyme-P (CYP)-3A4 and P-glycoprotein (P-gp) for drug concentrations. Materials and Methods: The modified in situ intestinal perfusion technique was developed and followed to obtain the portal and hepatic venous blood samples paralleled at different perfusion time and flow rates of 0.05, 0.1, 0.5, and 1.0 mL/min using the imatinib (1 mg/mL) drug alone and in the presence of drug inducer and drug inhibitor for the period of 3 h. The imatinib drug concentrations were assayed using high-pressure liquid chromatography. Results: The results reveal that the mean imatinib drug concentrations in portal vein were higher than hepatic vein at various perfusion flow rates and time intervals were observed. The area under curve and plasma drug concentrations maximum of imatinib alone absorptions were significantly different between portal and hepatic veins (p<0.05) at the flow rates of 0.5 and 1.0 mL/min and also in the presence of drug inducer and inhibitors that indicating for the considerable hepatic involvement in the presystemic extraction or metabolism of drugs. Conclusions: The in situ perfusions approach could provide the useful tool for improving the basic understanding of absorption kinetics and hepatic metabolism of drugs in the presence of drug inducers and drug inhibitors (CYP3A4 and P-gp) under the development and facilitating the clinical applications.

scholarly journals Inhibitory Effect of Berberine on Broiler P-glycoprotein Expression and Function: In Situ and In Vitro Studies

2019 ◽  
Vol 20 (8) ◽  
pp. 1966 ◽  
Author(s):  
Yujuan Zhang ◽  
Li Guo ◽  
Jinhu Huang ◽  
Yong Sun ◽  
Fang He ◽  
...  
Keyword(s):  
Molecular Docking ◽  
Inhibitory Effect ◽  
In Vitro Models ◽  
Apparent Permeability ◽  
Glycoprotein P ◽  
P Glycoprotein ◽  
And Function ◽  
Xenobiotic Receptor

Overcoming P-glycoprotein (P-gp) efflux is a strategy to improve the absorption and pharmacokinetics of its substrate drugs. Berberine inhibits P-gp and thereby increases the bioavailability of the P-gp substrate digoxin in rodents. However, the effects of berberine on P-gp in chickens are still unclear. Here, we studied the role of berberine in modulating broilers P-gp expression and function through both in situ and in vitro models. In addition, molecular docking was applied to analyze the interactions of berberine with P-gp as well as with chicken xenobiotic receptor (CXR). The results showed that the mRNA expression levels of chicken P-gp and CXR decreased in the ileum following exposure to berberine. The absorption rate constant of rhodamine 123 increased after berberine treatment, as detected using an in situ single-pass intestinal perfusion model. Efflux ratios of P-gp substrates (tilmicosin, ciprofloxacin, clindamycin, ampicillin, and enrofloxacin) decreased and the apparent permeability coefficients increased after co-incubation with berberine in MDCK-chAbcb1 cell models. Bidirectional assay results showed that berberine could be transported by chicken P-gp with a transport ratio of 4.20, and this was attenuated by verapamil (an inhibitor of P-gp), which resulted in a ratio of 1.13. Molecular docking revealed that berberine could form favorable interactions with the binding pockets of both CXR and P-gp, with docking scores of −7.8 and −9.5 kcal/mol, respectively. These results indicate that berberine is a substrate of chicken P-gp and down-regulates P-gp expression in chicken tissues, thereby increasing the absorption of P-gp substrates. Our findings suggest that berberine increases the bioavailability of other drugs and that drug-drug interactions should be considered when it is co-administered with other P-gp substrates with narrow therapeutic windows.

scholarly journals In vitro and in situ effects of atorvastatin and ezetimibe on P-glycoprotein expression and function

2016 ◽  
Vol 11 (4) ◽  
pp. 911
Author(s):  
Mehran Mesgari Abbasi ◽  
Hadi Valizadeh ◽  
Hamed Hamishehkar ◽  
Maryam Bannazadeh Amirkhiz ◽  
Parvin Zakeri-Milani
Keyword(s):  
Intestinal Permeability ◽  
High Performance ◽  
Video Clip ◽  
Permeability Model ◽  
Active Efflux ◽  
Single Pass ◽  
P Glycoprotein ◽  
And Function

<p class="Abstract">P-glycoprotein (P-gp) is a membrane transporter responsible for the active efflux from the cell. Inhibition of the activity may lead to clinically significant drug-drug interactions. This study was performed to investigate the effects of atorvastatin and ezetimibe on the function and expression of P-gp. The <em>in vitro</em> rhodamine-123 (Rho123) efflux assay and Western blot in Caco-2 cells, and the <em>in situ</em> rat single-pass intestinal permeability model followed by high performance liquid chromatography were developed. Rho123 intracellular accumulation in 100 µM of atorvastatin- and ezetimibe-treated cells was significantly higher than that in control cells (p&lt;0.05). P-gp expression was decreased by 100 µM atorvastatin and ezetimibe. Intestinal effective permeability of digoxin in the presence of atorvastatin (3 and 100 µM), ezetimibe (10 and 100 µM) was significantly increased (p&lt;0.05). Both drugs  inhibited P-gp activity in vitro and<em> in situ</em>. Atorvastatin and ezetimibe down-regulated the expression of P-gp <em>in vitro</em>. </p><p class="Abstract"><strong>Video Clip of Methodology</strong>:</p><p class="Abstract"><a href="https://youtube.com/v/BQuz1ER3_NQ">Single-pass intestinal permeability</a>: 17 min 26 sec</p><p> </p>

scholarly journals Intestinal Absorption of Geniposide and Inhibition of Transporter-P-GP Across the Caco-2 Monolayer

2020 ◽  
Author(s):  
Yanhong Bu ◽  
hong wu ◽  
MingHui Sun ◽  
Heng Zhang ◽  
Ran Deng ◽  
...  
Keyword(s):  
Intestinal Absorption ◽  
Cell Monolayer ◽  
Hplc Method ◽  
Transepithelial Transport ◽  
Absolute Bioavailability ◽  
Glycoprotein P ◽  
Gardenia Jasminoides ◽  
P Glycoprotein ◽  
Bioactive Component ◽  
Bidirectional Transport

Abstract Background: Geniposide (GE) is the main bioactive component of Gardenia jasminoides Ellis, which has many pharmacological effects, such as anti-inflammatory, anti-oxidation, and anti-angiogenesis. GE has low absolute bioavailability after oral administration, and speculated that GE might have an effect on P-glycoprotein (P-gp) described in our previous study. However, intestinal absorption characteristics involved in the Caco-2 cells of GE are still unknown. Therefore, we aimed to investigate absorption mechanisms of GE and the effects on P-gp. Methods: By establishing the Caco-2 cells model and HPLC method, bidirectional transport of GE in the different conditions and the presence of P-gp inhibitors－verapamil were conducted to observe its absorption mechanisms. Transport assays of digoxin, a P-gp substrate, were also performed in the presence of GE or verapamil. The effects of GE on the function and expression of P-gp were analyzed by flow cytometry and Western blot using rhodamine-123 (rho-123) and the antibody, respectively. Results: Both absorption and secretion of GE were positively correlated with concentration and time at Caco-2 cell monolayer. The Papp of bidirectional transport was decreased in low temperature and the Papp(BL-AP) of GE decreased significantly in the presence of verapamil. Meanwhile, the ER value was higher than 1.5. In addition, in the bidirectional transport of digoxin, the values of Papp(BL-AP) and ER decreased significantly in the presence of GE, just like verapamil. GE increased the intracellular accumulation of rho-123 and also have a significant decrease on P-gp expression. Conclusion: Transepithelial transport mechanism of GE in Caco-2 cell monolayer is mainly passive diffusion and P-gp mediated active transportation. GE was a potential inhibitor of P-gp, can inhibit transport of digoxin and the function and expression of P-gp.

scholarly journals Elucidation of the Intestinal Absorption Mechanism of Loganin in the Human Intestinal Caco-2 Cell Model

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Renjie Xu ◽  
Yichu Yuan ◽  
Jia Qi ◽  
Jia Zhou ◽  
Xiaowen Guo ◽  
...  
Keyword(s):  
Intestinal Absorption ◽  
Cell Model ◽  
Iridoid Glycosides ◽  
Cell Monolayer ◽  
Efflux Transporter ◽  
Cancer Resistance ◽  
Absorption Mechanism ◽  
Glycoprotein P ◽  
Active Efflux ◽  
Basolateral Side

Loganin, iridoid glycosides, is the main bioactive ingredients in the plant Strychnos nux-vomica L. and demonstrates various pharmacological effects, though poor oral bioavailability in rats. In this study, the intestinal absorption mechanism of loganin was investigated using the human intestinal Caco-2 cell monolayer model in both the apical-to-basolateral (A-B) and the basolateral-to-apical (B-A) direction; additionally, transport characteristics were systematically investigated at different concentrations, pHs, temperatures, and potential transporters. The absorption permeability (PappAB) of loganin, which ranged from 12.17 to 14.78 × 10−6cm/s, was high at four tested concentrations (5, 20, 40, and 80μM), while the major permeation mechanism of loganin was found to be passive diffusion with active efflux mediated by multidrug resistance-associated protein (MRP) and breast cancer resistance protein (BCRP). In addition, it was found that loganin was not the substrate of efflux transporter P-glycoprotein (P-gp) since the selective inhibitor (verapamil) of the efflux transporter exhibited little effects on the transport of loganin in the human intestinal Caco-2 cells. Meanwhile, transport from the apical to the basolateral side increased 2.09-fold after addition of a MRP inhibitor and 2.32-fold after addition of a BCRP inhibitor. In summary, our results clearly demonstrate, for the first time, a good permeability of loganin in the human intestinal Caco-2 cell model and elucidate, in detail, the intestinal absorption mechanism and the effects of transporters on iridoid glycosides compounds.

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