Carboxylesterase 2 and Intestine Transporters Contribute to the Low Bioavailability of Allisartan, a Prodrug of Exp3174 for Hypertension Treatment in Humans

Differential Tissue Abundance of Membrane-Bound Drug Metabolizing Enzymes and Transporter Proteins by Global Proteomics

Protein abundance data of drug-metabolizing enzymes and transporters (DMETs) are useful for scaling in vitro and animal data to humans for accurate prediction and interpretation of drug clearance and toxicity. Targeted DMET proteomics that relies on synthetic stable isotope-labeled surrogate peptides as calibrators is routinely used for the quantification of selected proteins; however, the technique is limited to the quantification of a small number of proteins. Although the global proteomics-based total protein approach (TPA) is emerging as a better alternative for large-scale protein quantification, the conventional TPA does not consider differential sequence coverage by identifying unique peptides across proteins. Here, we optimized the TPA approach by correcting protein abundance data by the sequence coverage, which was applied to quantify 54 DMETs for characterization of 1) differential tissue DMET abundance in the human liver, kidney, and intestine, and 2) interindividual variability of DMET proteins in individual intestinal samples (n = 13). Uridine diphosphate-glucuronosyltransferase 2B7 (UGT2B7), microsomal glutathione S-transferases (MGST1, MGST2, and MGST3) carboxylesterase 2 (CES2), and multidrug resistance-associated protein 2 (MRP2) were expressed in all three tissues, whereas, as expected, four cytochrome P450s (CYP3A4, CYP3A5, CYP2C9, and CYP4F2), UGT1A1, UGT2B17, CES1, flavin-containing monooxygenase 5, MRP3, and P-glycoprotein were present in the liver and intestine. The top three DMET proteins in individual tissues were: CES1>CYP2E1>UGT2B7 (liver), CES2>UGT2B17>CYP3A4 (intestine), and MGST1>UGT1A6>MGST2 (kidney). CYP3A4, CYP3A5, UGT2B17, CES2, and MGST2 showed high interindividual variability in the intestine. These data are relevant for enhancing in vitro to in vivo extrapolation of drug absorption and disposition and can be used to enhance the accuracy of physiologically based pharmacokinetic prediction of systemic and tissue concentration of drugs. SIGNIFICANCE STATEMENT: This study quantified the abundance and compositions of drug-metabolizing enzymes and transporters in pooled human liver, intestine, and kidney microsomes as well as individual intestinal microsomes using an optimized global proteomics approach. The data revealed large intertissue differences in the abundance of these proteins and high intestinal interindividual variability in the levels of cytochrome P450s (e.g., CYP3A4 and CYP3A5), uridine diphosphate-glucuronosyltransferase 2B17, carboxylesterase 2, and microsomal glutathione S-transferase 2. These data are applicable for the prediction of first-pass metabolism and tissue-specific drug clearance.

Efficacy and safety evaluation of Allisartan Isoproxil in patients with hypertension: a meta-analysis

Objective

This study aimed to evaluate the effectiveness and safety of Allisartan Isoproxil in the management of hypertension.

Methods

A comprehensive search was conducted across both English and Chinese databases, including the Cochrane Library, Embase, PubMed, Web of Science, Chinese Journal Full Text Database (CNKI), Wanfang Digital Periodical Full Text Database, and VIP Chinese Periodical Database (VIP), up to March 24, 2024. Randomized controlled trials (RCTs) investigating alisartan axetil for hypertension management were selected. Literature quality was assessed, and data were extracted for meta-analysis using Stata 15.1 software. The quality of evidence for outcome indicators was evaluated using the GRADE system level.

Results

Six RCTs involving 767 participants were included. Meta-analysis revealed that, compared to placebo, the Allisartan Isoproxil group exhibited a significant reduction in systolic blood pressure (SBP) [WMD = -8.08, 95% CI (-11.81, 4.10), p = 0.000] and brachial-ankle pulse wave velocity (baPWV) [SMD = -0.69, 95% CI (-1.17, 0.20), p = 0.006]. However, the reduction in diastolic blood pressure (DBP) was not statistically significant [WMD = -5.48, 95% CI (-11.07, 0.10), p = 0.054]. Additionally, compared to calcium channel blockers (CCB) and angiotensin II receptor blockers (ARB), Allisartan Isoproxil did not significantly affect SBP [WMD = 0.20, 95% CI (-3.71, 4.10), p = 0.921] or DBP [WMD = 0.16, 95% CI (-2.11, 2.43), p = 0.891]. Allisartan Isoproxil demonstrated superior effects in increasing nitric oxide (NO) levels and decreasing endothelin (ET) levels compared to control groups [WMD = 9.56, 95% CI (6.42, 12.71), p = 0.000], [WMD = -7.42, 95% CI (-11.13, -3.71), p = 0.000], and showed a higher effective control rate of blood pressure [RR = 1.26, 95% CI (1.13, 1.41), p = 0.000]. Subgroup analysis did not reveal significant differences. Regarding safety, there were no statistically significant differences in adverse events between the Allisartan Isoproxil group and the control groups [RR = 0.99, 95% CI (0.74, 1.32), p = 0.928], and no fatal adverse events were reported.

Conclusion

Allisartan Isoproxil is effective in reducing SBP and baPWV, increasing NO, decreasing ET, and achieving a higher control rate of blood pressure in patients with essential hypertension. These benefits are achieved with minimal adverse reactions.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42023467869, identifier PROSPERO CRD42023467869.

Transcriptome and proteome analyses reveal that upregulation of GSTM2 by allisartan improves cardiac remodeling and dysfunction in hypertensive rats

Long-term hypertension can lead to hypertensive heart disease, which ultimately progresses to heart failure. As an angiotensin receptor blocker antihypertensive drug, allisartan can control blood pressure, and improve cardiac remodeling and cardiac dysfunction caused by hypertension. The aim of the present study was to investigate the protective effects of allisartan on the heart of spontaneously hypertensive rats (SHRs) and the underlying mechanisms. SHRs were used as an animal model of hypertensive heart disease and were treated with allisartan orally at a dose of 25 mg/kg/day. The blood pressure levels of the rats were continuously monitored, their body and heart weights were measured, and their cardiac structure and function were evaluated using echocardiography. Wheat germ agglutinin staining and Masson trichrome staining were employed to assess the morphology of the myocardial tissue. In addition, transcriptome and proteome analyses were performed using the Solexa/Illumina sequencing platform and tandem mass tag technology, respectively. Immunofluorescence co-localization was conducted to analyze Nrf2 nuclear translocation, and TUNEL was performed to detect the levels of cell apoptosis. The protein expression levels of pro-collagen I, collagen III, phosphorylated (p)-AKT, AKT, p-PI3K and PI3K, and the mRNA expression levels of Col1a1 and Col3a1 were determined by western blotting and reverse transcription-quantitative PCR, respectively. Allisartan lowered blood pressure, attenuated cardiac remodeling and improved cardiac function in SHRs. In addition, allisartan alleviated cardiomyocyte hypertrophy and cardiac fibrosis. Allisartan also significantly affected the 'pentose phosphate pathway', 'fatty acid elongation', 'valine, leucine and isoleucine degradation', 'glutathione metabolism', and 'amino sugar and nucleotide sugar metabolism' pathways in the hearts of SHRs, and upregulated the expression levels of GSTM2. Furthermore, allisartan activated the PI3K-AKT-Nrf2 signaling pathway and inhibited cardiomyocyte apoptosis. In conclusion, the present study demonstrated that allisartan can effectively control blood pressure in SHRs, and improves cardiac remodeling and cardiac dysfunction. Allisartan may also upregulate the expression levels of GSTM2 in the hearts of SHRs and significantly affect glutathione metabolism, as determined by transcriptome and proteome analyses. The cardioprotective effect of allisartan may be mediated through activation of the PI3K-AKT-Nrf2 signaling pathway, upregulation of GSTM2 expression and reduction of cardiomyocyte apoptosis in SHRs.

Conversion of Olmesartan to Olmesartan Medoxomil, A Prodrug that Improves Intestinal Absorption, Confers Substrate Recognition by OATP2B1

PURPOSE

Olmesartan medoxomil (olmesartan-MX), an ester-type prodrug of the angiotensin II receptor blocker (ARB) olmesartan, is predominantly anionic at intestinal pH. Human organic anion transporting polypeptide 2B1 (OATP2B1) is expressed in the small intestine and is involved in the absorption of various acidic drugs. This study was designed to test the hypothesis that OATP2B1-mediated uptake contributes to the enhanced intestinal absorption of olmesartan-MX, even though olmesartan itself is not a substrate of OATP2B1.

METHODS

Tetracycline-inducible human OATP2B1- and rat Oatp2b1-overexpressing HEK 293 cell lines (hOATP2B1/T-REx-293 and rOatp2b1/T-REx-293, respectively) were established to characterize OATP2B1-mediated uptake. Rat jejunal permeability was measured using Ussing chambers. ARBs were quantified by liquid chromatography-tandem mass spectrometry.

RESULTS

Significant olmesartan-MX uptake was observed in hOATP2B1/T-REx-293 and rOatp2b1/T-REx-293 cells, whereas olmesartan uptake was undetectable or much lower than olmesartan-MX uptake, respectively. Furthermore, olmesartan-MX exhibited several-fold higher uptake in Caco-2 cells and greater permeability in rat jejunum compared to olmesartan. Olmesartan-MX uptake in hOATP2B1/T-REx-293 cells and in Caco-2 cells was significantly decreased by OATP2B1 substrates/inhibitors such as 1 mM estrone-3-sulfate, 100 µM rifamycin SV, and 100 µM fluvastatin. Rat Oatp2b1-mediated uptake and rat jejunal permeability of olmesartan-MX were significantly decreased by 50 µM naringin, an OATP2B1 inhibitor. Oral administration of olmesartan-MX with 50 µM naringin to rats significantly reduced the area under the plasma concentration-time curve of olmesartan to 76.9%.

CONCLUSION

Olmesartan-MX is a substrate for OATP2B1, and the naringin-sensitive transport system contributes to the improved intestinal absorption of olmesartan-MX compared with its parent drug, olmesartan.

Biologically active metabolites in drug discovery

Biologically active metabolites are a valuable resource for development of drug candidates and lead structures for drug design. This digest highlights a selection of biologically active metabolites that have been used as new chemical entities for development or as lead structures for drug design.

Comparison of Cellular Monolayers and an Artificial Membrane as Absorptive Membranes in the in vitro Lipolysis-permeation Assay

Permeation across Caco-2 cells in lipolysis-permeation setups can predict the rank order of in vivo drug exposure obtained with lipid-based formulations (LBFs). However, Caco-2 cells require a long differentiation period and do not capture all characteristics of the human small intestine. We therefore evaluated two in vitro assays with artificial lecithin-in-dodecane (LiDo) membranes and MDCK cells as absorptive membranes in the lipolysis-permeation setup. Fenofibrate-loaded LBFs were used and the results from the two assays compared to literature plasma concentrations in landrace pigs administered orally with the same formulations. Aqueous drug concentrations, supersaturation, and precipitation were determined in the digestion chamber and drug permeation in the receiver chamber. Auxiliary in vitro parameters were assessed, such as permeation of the taurocholate, present in the simulated intestinal fluid used in the assay, and size of colloidal structures in the digestion medium over time. The LiDo membrane gave a similar drug distribution as the Caco-2 cells and accurately reproduced the equivalent rank-order of fenofibrate exposure in plasma. Permeation of fenofibrate across MDCK monolayers did not, however, reflect the in vivo exposure rankings. Taurocholate flux was negligible through either membrane. This process was therefore not considered to significantly affect the in vitro distribution of fenofibrate. We conclude that the artificial LiDo membrane is a promising tool for lipolysis-permeation assays to evaluate LBF performance.

Pharmacokinetics and Safety of a Single Dose and Multiple Doses of Allisartan Isoproxil, an Angiotensin II Receptor Blocker, in Healthy Chinese People

Allisartan isoproxil (AI) is a blocker of the angiotensin II type 1 receptor. We evaluated the safety and pharmacokinetics of single- and multiple-dose AI in healthy Chinese individuals. Participants were assigned to receive AI or placebo. Plasma concentration of EXP3174 (carboxylic acid derivative) was measured using liquid chromatography-tandem mass spectrometry. Pharmacokinetic parameters were determined by noncompartmental methods. Twelve subjects were enrolled, and the ratio of men to women was 5:1. Main pharmacokinetic parameters of EXP3174 after single and multiple doses of AI were a mean maximum concentration in plasma (C_max ) of 2242 ± 1037 ng/mL and median time to reach C_max (T_max ) of 3.5 hours (2.5-8 hours). The median T_max, at steady state was 4.0 hours (1.5-8 hours). The mean C_max at steady state (C_{max, SS} ) was 2047 ± 1050 ng/mL. In terms of EXP3174, there was no significant difference in the C_{max, SS} , area under the curve from time zero to 24 hours of quantifiable concentration at steady state (AUC_{0-24 SS} ), and AUC_0-72 after multiple doses of AI. Serious adverse events did not occur. These data suggest that AI is safe and well tolerated in healthy Chinese individuals at a single dose of 480 or 480 mg once daily for 7 days.

A highly selective near infrared fluorescent probe for carboxylesterase 2 and its biological applications

Carboxylesterase 2 (CES 2) is a key enzyme in the activation of the prodrug irinotecan (CPT-11) in the treatment against colorectal cancer and also has some relationship with the side effect of CPT-11 in clinical applications. Herein, a near infrared (NIR) fluorescent probe (DSAB) has been designed for CES 2 which possesses the advantages of prominent selectivity and high sensitivity, and DSAB has been successfully applied for the imaging of endogenous CES 2 in living cells. Moreover, a high-throughput screening method for CES 2 inhibitors has been established using DSAB and discovered four novel CES 2 inhibitors from various herbal medicines. These results fully demonstrated that DSAB is a promising molecular tool for the investigation of the biological functions of CES 2 in living systems and the discovery of novel CES 2 inhibitors for the treatment of CES 2 related physiological diseases.

2020 FDA Drug-drug Interaction Guidance: A Comparison Analysis and Action Plan by Pharmaceutical Industrial Scientists

Background:

In January 2020, the US FDA published two final guidelines, one entitled “In vitro Drug Interaction Studies - Cytochrome P450 Enzyme- and Transporter-Mediated Drug Interactions Guidance for Industry” and the other entitled “Clinical Drug Interaction Studies - Cytochrome P450 Enzyme- and Transporter-Mediated Drug Interactions Guidance for Industry”. These were updated from the 2017 draft in vitro and clinical DDI guidance.

Methods:

This study is aimed to provide an analysis of the updates along with a comparison of the DDI guidelines published by the European Medicines Agency (EMA) and Japanese Pharmaceuticals and Medical Devices Agency (PMDA) along with the current literature.

Results:

The updates were provided in the final FDA DDI guidelines and explained the rationale of those changes based on the understanding from research and literature. Furthermore, a comparison among the FDA, EMA, and PMDA DDI guidelines are presented in Tables 1, 2 and 3.

Conclusion:

The new 2020 clinical DDI guidance from the FDA now has even higher harmonization with the guidance (or guidelines) from the EMA and PMDA. A comparison of DDI guidance from the FDA 2017, 2020, EMA, and PMDA on CYP and transporter based DDI, mathematical models, PBPK, and clinical evaluation of DDI is presented in this review.

Study on the Formation of Antihypertensive Twin Drugs by Caffeic Acid and Ferulic Acid with Telmisartan

PURPOSE

This study aimed to synthesize twin drugs from cinnamic acid compounds, caffeic acid (CFA) and ferulic acid (FLA), which can antagonize endothelin-1 (ET-1) with telmisartan through ester bonds. Moreover, the antihypertensive effect of telmisartan and its influence on blood pressure variability (BPV) were enhanced, and the bioavailability of caffeic acid and ferulic acid was improved.

METHODS

Six twin drugs, which were the target compounds, were synthesized. Hypertensive rats (SHR) and conscious sinoaortic-denervated (SAD) rats were spontaneously used as models for pharmacodynamic research to study the antihypertensive efficacy of these twin drugs. Wistar rats were employed as pharmacokinetic research models to investigate the pharmacokinetics of the target compounds via intragastric administration. Cellular pharmacodynamic research was also conducted on the antagonistic action on Ang II-AT1, ETA and ETB receptor.

RESULTS

Compound 1a was determined as the best antihypertensive twin drug and thus was further studied for its effect on BPV. Compared with that of telmisartan, the antihypertensive effect of compound 1a was improved (p<0.05), and the BPV was reduced (p<0.05). The bioavailability of caffeic acid and ferulic acid after hydrolysis from twin drugs could be increased to varying degrees, and the differences of the main pharmacokinetic parameters among the different forms of caffeic acid and ferulic acid were statistically significant (p<0.05 or p<0.01). Compound 1a had the best antagonistic effect on the Ang II-AT1 receptor. However, the IC50 of Lps-2 was still two orders of magnitude higher than that of the positive drug telmisartan. Hence, the twin drugs worked by metabolizing and regenerating telmisartan and caffeic acid or ferulic acid in the body.

CONCLUSION

The synthesized twin drugs improved telmisartan's antihypertensive effects, significantly decreased BPV in SAD rats and increased the bioavailability of caffeic acid and ferulic acid. This study serves as a basis for the development of new angiotensin receptor blocker (ARB) in the future and a reference for the development of new drugs to antagonize ET-1.