Zilebesiran, an RNA Interference Therapeutic Agent for Hypertension.

BACKGROUND: Angiotensinogen is the sole precursor of angiotensin peptides and has a key role in the pathogenesis of hypertension. Zilebesiran, an investigational RNA interference therapeutic agent with a prolonged duration of action, inhibits hepatic angiotensinogen synthesis. METHODS: In this phase 1 study, patients with hypertension were randomly assigned in a 2:1 ratio to receive either a single ascending subcutaneous dose of zilebesiran (10, 25, 50, 100, 200, 400, or 800 mg) or placebo and were followed for 24 weeks (Part A). Part B assessed the effect of the 800-mg dose of zilebesiran on blood pressure under low- or high-salt diet conditions, and Part E the effect of that dose when coadministered with irbesartan. End points included safety, pharmacokinetic and pharmacodynamic characteristics, and the change from baseline in systolic and diastolic blood pressure, as measured by 24-hour ambulatory blood-pressure monitoring. RESULTS: Of 107 patients enrolled, 5 had mild, transient injection-site reactions. There were no reports of hypotension, hyperkalemia, or worsening of renal function resulting in medical intervention. In Part A, patients receiving zilebesiran had decreases in serum angiotensinogen levels that were correlated with the administered dose (r = -0.56 at week 8; 95% confidence interval, -0.69 to -0.39). Single doses of zilebesiran (≥200 mg) were associated with decreases in systolic blood pressure (>10 mm Hg) and diastolic blood pressure (>5 mm Hg) by week 8; these changes were consistent throughout the diurnal cycle and were sustained at 24 weeks. Results from Parts B and E were consistent with attenuation of the effect on blood pressure by a high-salt diet and with an augmented effect through coadministration with irbesartan, respectively. CONCLUSIONS: Dose-dependent decreases in serum angiotensinogen levels and 24-hour ambulatory blood pressure were sustained for up to 24 weeks after a single subcutaneous dose of zilebesiran of 200 mg or more; mild injection-site reactions were observed. (Funded by Alnylam Pharmaceuticals; ClinicalTrials.gov number, NCT03934307; EudraCT number, 2019-000129-39.).

Pharmacokinetic study on the interaction between succinic acid and irbesartan in rats and its potential mechanism.

CONTEXT: Succinic acid and irbesartan are commonly used drugs in cardiovascular disease treatment. The interaction might occur during their co-administration, which was still unclear. OBJECTIVE: To reveal the effect of succinic acid on the metabolism of irbesartan and its potential mechanism. MATERIALS AND METHODS: The Sprague-Dawley rats (n = 6) were treated with a single dose of 30 mg/kg irbesartan (control) or the co-administration with the pre-treatment of 200 mg/kg succinic acid for 7 d. The effect of succinic acid on the metabolic stability and the activity of CYP2C9 was evaluated in rat liver microsomes. RESULTS: Succinic acid increased the AUC (5328.71 ± 959.31 µg/L × h vs. 3340.23 ± 737.75 µg/L × h) and prolonged the half-life of irbesartan (from 12.79 ± 0.73 h to 20.59 ± 6.35 h). The Tmax (2.83 ± 0.75 h vs. 3.83 ± 1.10 h) and clearance rate (3.46 ± 1.13 L/h/kg vs. 6.91 ± 1.65 L/h/kg) of irbesartan was reduced by succinic acid. Consistently, succinic acid improved the metabolic stability (half-life from 23.32 ± 3.46 to 27.35 ± 2.15 min, intrinsic clearance rate from 59.43 ± 6.12 to 50.68 ± 5.64 µL/min/mg protein). Succinic acid was also found to inhibit the activity of CYP2C9 with the IC50 value of 13.87 µM. DISCUSSION AND CONCLUSIONS: Succinic acid increased the system exposure of irbesartan via inhibiting CYP2C9. The experiment design of this study also provides a reference for the further validation of this interaction in humans.

A rapid LC-MS/MS method for simultaneous determination of berberine and irbesartan in rat plasma: Application to the drug-drug pharmacokinetic interaction study after oral administration in rats.

A sensitive, reproducible, and specific liquid chromatography tandem mass spectrometry method was developed and validated to simultaneously determine the concentration of berberine (BBR) and irbesartan in Sprague-Dawley rat plasma, and applied to study the pharmacokinetic drug-drug interaction (DDI) between BBR and irbesartan in rats. In this method, diphenhydramine was used as the internal standard, and the liquid-liquid extraction method using ethyl acetate as the extraction agent was used for sample preparation. After extraction, the prepared samples were run on an Agilent Welchrom C18 column with the mobile phase consisting of methanol-acetonitrile-water solution with 0.5% formic acid (45:50:5, v/v/v) at a flow rate of 0.8 mL·min-1 . The analytes BBR, irbesartan, and diphenhydramine (IS) were detected using multiple reactions monitoring mode, with the ion transitions being m/z 336.1 → m/z 320.0, m/z 429.1 → m/z 206.9, and m/z 256.2 → m/z 167.0, respectively. In the rats' plasma, BBR had good linearity in the range of 0.5-100 ng·mL-1 with the lower limit of quantitation of 0.5 ng·mL-1 , and the accuracy, intra-day, and inter-day precision were less than 12.33%. Irbesartan had good linearity in the range of 20-1200 ng·mL-1 with the lower limit of quantification of 20 ng·mL-1 , and the accuracy, intra-day, and inter-day precision were less than 13.55%. The validated method was verified to meet the determination requirements of biological samples. It was the first time to study the pharmacokinetics of DDI between BBR and irbesartan successfully, which would be necessary and beneficial to explore the clinical safety and efficacy of the combination of BBR and irbesartan in the treatment of diabetic nephropathy.

An LC-MS/MS spectrometry method for the simultaneous determination of Rosuvastatin and Irbesartan in rat plasma: Insight into pharmacokinetic and drug-drug interaction studies.

The synergistic vascular protective effect of statins and angiotensin receptor blockers (ARBs) is well known, however, the pharmacokinetic interaction among these classes is yet to be understood and the necessity of developing analytical methods for their determination in vivo is gradually increased. Herein, first chromatographic separation coupled tandem mass spectrometric was developed and fully validated for simultaneous measurement of rosuvastatin (ROS) and irbesartan (IRB) in rat plasma after oral administration. The two analytes were extracted from plasma sample using acetonitrile-induced protein precipitation then separated on an Agilent Eclipse Plus ODS (4.6 × 100 mm, 3.5 µm) column by gradient elution using 6 mM ammonium formate/0.1% formic acid and ACN at a flow rate 0.4 mL min-1. Multiple reaction monitoring in positive ion mode was used for quantification of precursor to production at m/z 492.1 → 206.9 for IRB, 482.1 → 258.1 for ROS, and 409.2 → 238.2 for the internal standard, amlodipine (AML). Linearity was obeyed in the range of 1-10000 ng mL-1 and 1-5000 ng mL-1 with detection limits (S/N of 3) of 0.05 and 0.07 ng mL-1 for IRB and ROS, respectively. The current method was validated in terms of selectivity, recovery, accuracy, precision, matrix effects, and stability as per US-FDA bioanalytical guidelines. The application of our method reported her is the first to study pharmacokinetic interaction of IRB and ROS in rat plasma after a single oral dose. The area under the concentration-time curve (AUC), peak plasma concentrations (Cmax), half-life time (t1/2), and volume of distribution (Vd) of ROS and IRB were affected when the two drugs were co-administering. The current study provided a valuable tool for studying drug-drug interaction and might be useful for therapeutic drug monitoring and bioequivalence studies.

Development and validation of reverse phase HPLC method for determination of angiotensin receptor blocking agent irbesartan in plasma.

A sensitive, reproducible and modest analytical procedure was developed and validated for evaluation of irbesartan in human plasma. LLE (Liquid-Liquid extraction) of the drug was carried out with acetonitrile (1:1 v/v). Chromatographic separation of irbesartan was conducted by the help of 4.0mm × 25cm column having L1 packing from plasma and mobile phase utilizing HPLC. The mobile phase comprise of phosphate buffer and acetonitrile in a ratio of 67:33 v/v. The flow rate was set at 1ml/minute and the detector at a wavelength of 220 nm. The resolution of irbesartan was well performed from plasma components. This method was validated and demonstrated linearity with a concentration range of 0.1to 6µg/ml of irbesartan in plasma. Intra-day, inter-day accuracy was found 89.33% to 96.37% while intra-day, inter-day precision was found within the limit of 0.02 and 2.15 respectively. The mean recovery of irbesartan was 97.28%. The efficacy of extraction was proved by above-mentioned results. In plasma, the 0.05 and 0.1µg/ml dilutions were exhibited as the LOD and LOQ of irbesartan. Stability studies disclosed that irbesartan showed stability at -20°C storage.

Modeling the drug release from reduced graphene oxide-reinforced hyaluronic acid/gelatin/poly(ethylene oxide) polymeric films.

Herein, electroconductive polymeric films consisting of hyaluronic acid (HyA), gelatin (Gel), poly(ethylene oxide) (PEO) reinforced by reduced graphene oxide (RGO) were used in drug release studies to investigate usability of the films as drug carrier in the future. Irbesartan (IRB) used for the treatment of cardiovascular diseases was loaded to the polymeric films and its release kinetic was investigated. Afterwards, the obtained controlled drug release data were simulated using different dynamic differential mathematical models such as 1st, 2nd, 3rd degree and Higuchi model. In addition, a novel approach considering the drug release rate to be inversely proportional to the drug release percentage was presented to reproduce the experimental drug release percentage results. Thus, the approach used in this work covers different aspects of drug release kinetics to assure that HyA/Gel/PEO films w/out RGO could be considered as a potential carrier for controlled drug delivery systems.

18 F-Labeled Derivatives of Irbesartan for Angiotensin†II Receptor PET Imaging.

The renin angiotensin aldosterone system (RAAS) is a hormonal cascade involved in the regulation of blood pressure and electrolyte balance, and represents a common target for the treatment of various diseases including hypertension, heart failure, and diabetes. Herein we present a novel 18 F-labeled derivative of the drug irbesartan, one of the most prescribed angiotensin II type 1 receptor (AT1 R) antagonists, for in vivo positron emission tomography (PET). This allows the in vivo measurement of AT1 R expression, and thus the evaluation of functional changes in its expression under pathophysiological conditions. We followed various synthetic approaches optimized for the introduction of fluorine into different positions of the aliphatic side chain of irbesartan. Radioligand binding studies revealed that fluorine atoms at specified positions (α-position (IC50 =6.6 nm) and δ-position (IC50 =8.5 nm) of the aliphatic side chain) do not alter the binding properties of irbesartan (IC50 =1.6 nm). After successful radiolabeling with fluorine-18 in a radiochemical yield of 11 %, we observed high renal uptake in healthy rats and pigs, which could be decreased by pretreatment with the parent compound irbesartan.

Impact of Drug-Polymer Miscibility on Enthalpy Relaxation of Irbesartan Amorphous Solid Dispersions.

PURPOSE: Drug-polymer miscibility has been proposed to play a critical role in physical stability of amorphous solid dispersions (ASDs). The purpose of the current work was to investigate the role of drug-polymer miscibility on molecular mobility, measured as enthalpy relaxation (ER) of amorphous irbesartan (IBS) in ASDs. METHODS: Two polymers, i.e. polyvinylpyrrolidone K30 (PVP K30) and hydroxypropyl methylcellulose acetate succinate (HPMCAS), were used to generate ASDs with 10% w/w of the polymer. Drug-polymer miscibility was determined using melting point depression (MPD) method. Molecular mobility was assessed from ER studies at a common degree of undercooling (DOU) (Tg - 13.0°C ± 0.5°C). RESULTS: IBS exhibited higher miscibility in PVP K30 as compared to HPMCAS at temperature > 140°C. However, extrapolation of miscibility data to storage temperature (62°C) using Flory-Huggins (F-H) theory revealed a reversal of the trend. Miscibility of IBS was found to be higher in HPMCAS (2.6%) than PVP K30 (1.3%) at 62°C. Stretched relaxation time (τß) of 17.4365 h and 7.0886 h was obtained for IBS-HPMCAS and IBS-PVP K30 ASDs, respectively. CONCLUSION: Miscibility of drug-polymer at storage temperature explained the behavior of the molecular mobility, while miscibility near the melting point provided a reverse trend. Results suggest that drug-polymer miscibility determined at temperatures higher than the storage temperature should be viewed cautiously.