Determination of sacubitril and seven sartan drugs in serum samples by online solid phase extraction-liquid chromatography-tandem mass spectrometry

An online solid phase extraction-ultra performance liquid chromatography-tandem mass spectrometry detection method was developed for the simultaneous determination of sacubitril and seven sartan drugs in blood serum in this study. The compounds were separated through a C18 column. Mass spectrometry of the samples was performed using a jet stream electrospray ion source (AJS, ESI+). The samples were detected via a multiple reaction monitoring (MRM) mode and quantified via a stable isotope internal standard method. 900 μL of prepared sample was injected and a run time of 12.5 minutes was obtained in this proposed method. The eight examined target compounds showed good linearity (r2＞0.994) in the corresponding mass concentration range and a lower limit of quantitation (LLOQ) was in the range of 0.05-0.1 μg/L. The recovery of the spiked serum samples ranged from 90.90 % to 106.20 % with relative standard deviations (RSDs) of 4.57 %-9.27 %. Five target compounds were detected in the actual serum samples using this method. The proposed method is simple to use, sensitive, accurate, and suitable for the trace detection of sacubitril and seven sartan drugs present in serum samples. The method can meet the needs for clinical monitoring of blood concentrations of this type of drug, while providing detection technology support for the development of compound preparations of sacubitril and other sartan drugs.

DNA-dependent protein kinase catalytic subunit (DNA-PKcs) drives angiotensin II-induced vascular remodeling through regulating mitochondrial fragmentation

BACKGROUND

DNA-dependent protein kinase catalytic subunit (DNA-PKcs) is a novel instigator for mitochondrial dysfunction, and plays an important role in the pathogenesis of cardiovascular diseases. However, the role and mechanism of DNA-PKcs in angiotensin II (Ang II)-induced vascular remodeling remains obscure.

METHODS

Rat aortic smooth muscle cells (SMC) and VSMC-specific DNA-PKcs knockout (DNA-PKcsΔVSMC) mice were employed to examine the role of DNA-PKcs in vascular remodeling and the underlying mechanisms. Blood pressure of mice was monitored using the tail-cuff and telemetry methods. The role of DNA-PKcs in vascular function was evaluated using vascular relaxation assessment.

RESULTS

In the tunica media of remodeled mouse thoracic aortas, and renal arteries from hypertensive patients, elevated DNA-PKcs expression was observed along with its cytoplasmic translocation from nucleus, suggesting a role for DNA-PKcs in vascular remodeling. We then infused wild-type (DNA-PKcsfl/fl) and DNA-PKcsΔVSMC mice with Ang II for 14 days to establish vascular remodeling, and demonstrated that DNA-PKcsΔVSMC mice displayed attenuated vascular remodeling through inhibition of dedifferentiation of VSMCs. Moreover, deletion of DNA-PKcs in VSMCs alleviated Ang II-induced vasodilation dysfunction and hypertension. Mechanistic investigations denoted that Ang II-evoked rises in cytoplasmic DNA-PKcs interacted with dynamin-related protein 1 (Drp1) at its TQ motif to phosphorylate Drp1S616, subsequently promoting mitochondrial fragmentation and dysfunction, as well as reactive oxygen species (ROS) production. Treatment of irbesartan, an Ang II type 1 receptor (AT1R) blocker, downregulated DNA-PKcs expression in VSMCs and aortic tissues following Ang II administration.

CONCLUSION

Our data revealed that cytoplasmic DNA-PKcs in VSMCs accelerated Ang II-induced vascular remodeling by interacting with Drp1 at its TQ motif and phosphorylating Drp1S616 to provoke mitochondrial fragmentation. Maneuvers targeting DNA-PKcs might be a valuable therapeutic option for the treatment of vascular remodeling and hypertension.

Autophagy modulation by irbesartan mitigates the pulmonary fibrotic alterations in bleomycin challenged rats: Comparative study with rapamycin

AIMS

In pulmonary fibrosis, autophagy handles the maintenance of alveolar epithelial cells, prevents epithelial-mesenchymal transition (EMT), and controls collagen turnover. The mammalian target of rapamycin (mTOR) and its translational-dependent proteins are essential regulators of autophagy. Irbesartan (IRB) has earlier ameliorative effects in experimental pulmonary fibrosis. The current study aimed to explore therapeutic autophagy-modulated pulmonary fibrotic changes by IRB versus rapamycin (RAPA) in bleomycin (BLM)-challenged rats.

MATERIALS AND METHODS

A single intratracheal BLM dose at day (0), IRB in different doses (10, 20, and 40 mg/kg) or RAPA (2.5 mg/kg) was given daily for 14 continuous days.

KEY FINDINGS

IRB significantly diminished the fibrotic lung scores. Pulmonary levels of transforming growth factor (TGF)-β1 and hydroxyproline exhibited marked attenuation in IRB (40 mg/kg)-treated rats compared to other treated groups. IRB (40 mg/kg) was not significantly different from RAPA. It downregulated the fibrotic lung phosphorylated mammalian target of rapamycin (p-mTOR) levels and augmented lung Unc-51-like autophagy activating kinase 1 (ULK1), LC3-I and LC3-II more than IRB (10 and 20 mg/kg)-treated fibrotic groups.

SIGNIFICANCE

Autophagic effects via the mTOR signalling pathway may play a role in IRB's antifibrotic effects. Consideration of IRB as a therapeutic antifibrotic agent in pulmonary fibrosis needs further experimental and clinical long-term validation, especially in comorbid with primary hypertension, heart failure, and diabetic renal insults.

Comparison of efficacy and safety between two different irbesartan, generic vs branded, in the treatment of Korean patients with mild-to-moderate hypertension: an 8-week, multicenter, randomized, open-label, Phase IV clinical study

Purpose

This study aimed to compare the efficacy and safety of generic and branded irbesartan for 8 weeks in patients with mild-to-moderate essential hypertension.

Patients and methods

We screened 221 patients with mild-to-moderate hypertension. After exclusion per study criteria, 177 subjects were randomized to receive 150 mg generic irbesartan (n=91) or branded irbesartan (n=86) as the intention to treat set. The primary efficacy endpoint of this study was the change in mean sitting diastolic blood pressure (SiDBP) from baseline to 8 weeks between the generic and branded irbesartan groups. The secondary efficacy endpoints were the change in mean SiDBP at Week 4 from baseline and the change in mean sitting systolic blood pressure (SiSBP) at Weeks 4 and 8 from baseline in both groups. All safety issues were evaluated.

Results

At Week 8, the generic and branded irbesartan groups showed significantly reduced SiDBP (-10.3±8.0, -10.7±7.7 mmHg, all P<0.0001) compared with baseline values, and the mean between-group difference in SiDBP change after 8 weeks of treatment was -0.4±1.2 mmHg, showing the non-inferiority of generic irbesartan vs branded irbesartan. Furthermore, secondary efficacy, which was the mean change of SiDBP from baseline at 4 weeks, was comparable between the two groups (-9.4±8.1 vs -9.9±7.4 mmHg, P=0.69). There were no between-group differences in mean changes of SiSBP after 4 or 8 weeks of treatment (P=0.78, P=0.97, respectively), or in the incidence of adverse effects (16.7 vs 24.4%, P=0.20).

Conclusion

Generic irbesartan treatment in patients with mild-to-moderate essential hypertension has shown effective antihypertensive effects comparable with the branded irbesartan treatment, with similar incidence of adverse effects.

The therapeutic advantage of combination antihypertensive drug therapy using amlodipine and irbesartan in hypertensive patients: Analysis of the post-marketing survey data from PARTNER (Practical combination therapy of Amlodin and angiotensin II Receptor blocker; safety and efficacy in patients with hypertension) study

Two-thirds of hypertensive patients need a combination antihypertensive therapy to achieve the target blood pressure (BP). The PARTNER (Practical combination therapy of Amlodin and angiotensin II Receptor blocker; Safety and efficacy in paTieNts with hypERtension) study is a prospective specific clinical use survey examining the efficacy and safety of 12-week treatment with amlodipine (AML) and Angiotensin II Receptor Blocker (ARB) in 5900 hypertensive patients. The current analysis was performed as to the BP control, adverse reactions, and the effects on laboratory data in patients treated with the combination of AML and irbesartan (IRB), namely the patients added AML to already taking IRB (AML add-on group, n = 1202) and the patients added IRB to AML (IRB add-on group, n = 1050). Both study groups showed distinct decreases in office BP at 4 week (p < 0.001) and the antihypertensive effects were sustained to 12 week (p < 0.001). The percentage of patients achieving BP < 140/90 mmHg was ∼70% in either group. Proteinuria and estimated glomerular filtration rate (eGFR) were significantly improved in hypertensive patients with baseline eGFR <60 ml/min/1.73 m(2). Serum uric acid was reduced either by adding AML or IRB, and the reductions were prominent in patients with serum uric acid >7 mg/dl. The incidence of adverse reactions was as few as 1.11% and there were no severe adverse reactions which hampered the continuation of combination therapy. In conclusion, combination antihypertensive therapy with AML and IRB effectively lowers BP without particular safety problems, reduces serum uric acid especially in patients with hyperuricemia and exhibits renoprotective effects in patients with chronic kidney disease.

Pharmacokinetics and pharmacodynamics (PK/PD) of irbesartan in Beagle dogs after oral administration at two dose rates

Irbesartan (Irb) is an angiotensin II type 1 receptor antagonist widely used in humans to treat hypertension. Age-related diseases such as hypertension are increasingly being diagnosed in dogs and there is the need for new drugs. The PK/PD of Irb was tested in Beagle dogs. Ten healthy Beagles were orally administered two dose rates (2 and 5 mg/kg), according to a cross over study design. Blood collections for PK analysis and systolic blood pressure (SBP), heart and respiratory rate, mucous membranes colour, capillary refill time and temperature evaluations were performed at scheduled intervals. The drug plasma concentration was dose dependent. The dogs administered 5 mg/kg showed a significant reduction in SBP, while in those receiving 2 mg/kg, this parameter was minimally affected. A counter clockwise hysteresis showed no direct correlation between SBP and plasma concentrations. The minimum effective concentration was theorized to be within the range 550-800 ng/mL. Although further studies are necessary, 5 mg/kg seems to be the more appropriate dose to obtain a hypotensive effect in Beagle dogs.

Irbesartan/amlodipine: a review of its use in adult patients with essential hypertension not adequately controlled with monotherapy

Combination therapy is often required in patients with hypertension, and fixed-dose single-pill combinations have been shown to provide an easier regimen for patients, improving adherence. Irbesartan/amlodipine (Aprovasc®) is an angiotensin-receptor blocker/calcium-channel blocker fixed-dose single-pill combination, whose constituent drugs exert additive effects when coadministered. In two randomized, open-label, multicentre, phase III trials, fixed-dose combination therapy with irbesartan/amlodipine was more effective than continuation of irbesartan or amlodipine monotherapy in patients with hypertension not adequately controlled with initial irbesartan or amlodipine monotherapy; there was a significantly greater decrease from baseline in mean seated home systolic blood pressure (primary endpoint) with the fixed-dose combination. The fixed-dose combination was also associated with a greater decrease in mean seated home diastolic blood pressure and mean seated office systolic and diastolic blood pressure than monotherapy. The fixed-dose combination of irbesartan/amlodipine was well tolerated in these patients; most treatment-emergent adverse events were of mild or moderate severity. The most frequent adverse event was peripheral oedema, generally associated with amlodipine treatment.

Comparative efficacy of irbesartan/ hydrochlorothiazide and valsartan/hydrochlorothiazide combination in lowering blood pressure: a retrospective observational study in Oman

OBJECTIVE

To compare blood pressure (BP) control in patients receiving irbesartan/hydrochlorothiazide (HCTZ) and valsartan/HCTZ at a tertiary care university hospital in Oman.

SUBJECTS AND METHODS

This was a retrospective observational study, where 232 patients' medical records were reviewed during a 3-month period, July to September 2010, at Sultan Qaboos University Hospital in Oman. BP readings of the previous 6 months were also retrieved from the electronic medical records. Analyses were conducted using univariate statistical techniques.

RESULTS

The mean age of the cohort was 58 ± 11 years (range: 21-88). Sixty-nine (30%) patients were on the irbesartan/HCTZ combination (150/12.5 mg) and 163 (70%) were on the valsartan/HCTZ combination. The patients on the valsartan/HCTZ combination were divided into two subgroups: 117 (72%) received 160/12.5 mg and 46 (28%) 80/12.5 mg. Diabetic patients (43/69, 62%, vs. 61/163, 37%, p < 0.001) and those with diabetic nephropathy (8/69, 12%, vs. 7/163, 4%, p = 0.039) were prescribed more often irbesartan/HCTZ than valsartan/HCTZ. In comparison to the valsartan/HCTZ cohort, the irbesartan/HCTZ group was associated with significant reductions in both systolic BP (SBP; -9 vs. -2 mm Hg; p = 0.021) and diastolic BP (DBP; -5 vs. 0 mm Hg; p = 0.022). BP reductions were noted more in diabetics than nondiabetics with the irbesartan/HCTZ patients associated with significant reductions in both SBP (-12 vs. 5.1 mm Hg; p < 0.001) and DBP (-6.4 vs. 1.9 mm Hg; p = 0.001).

CONCLUSIONS

The irbesartan/HCTZ combination was associated with significant reductions in both SBP and DBP when compared with the valsartan/HCTZ combination. Specifically, the reductions were noted more in diabetics than nondiabetics.

The pharmacokinetics and pharmacodynamics of valsartan in the post-myocardial infarction population

INTRODUCTION

The most common risk factors for heart failure are hypertension and myocardial infarction. Angiotensin receptor blockers (ARBs) attenuate the deleterious effects of angiotensin II. Valsartan is a once or twice daily ARB that is FDA-approved for hypertension, LV dysfunction post-myocardial infarction and congestive heart failure as both an adjunct in ACE-inhibitor tolerant, and alternative in ACE-I intolerant patients.

AREAS COVERED

This article presents a comprehensive review of the literature regarding the pharmacokinetics and pharmacodynamics of valsartan, with particular attention paid to the post-myocardial infarction population.

EXPERT OPINION

Valsartan is a safe, well-tolerated and readily titratable ARB. In addition to its vasodilatory effects there are pleotropic effects associated with the ARB such as modulation of a number of neurohormonal regulators, cytokines and small molecules. Given the clear evidence-based benefits above and beyond its hypertensive properties, it has the potential, if priced appropriately, to grow in its impact as a pharmacotherapeutic long after its patent expires.

Effects of angiotensin II receptor blocker on myocardial endothelial-to-mesenchymal transition in diabetic rats

BACKGROUND

Emerging evidence has indicated that the endothelial-to-mesenchymal transition (EndMT) is a crucial event during early stages of cardiac fibrosis. In the present study, we first investigated the influence of Irbesartan (Irb) on myocardial EndMT in diabetic rats.

METHODS

Diabetic rats were divided into two groups: the diabetic group (DM) and the Irb-treated group (DM+Irb). Wistar-Kyoto rats served as controls. The pathological changes were investigated by microscopy. Immunofluorescence was performed to evaluate the co-expression of CD31 and fibroblast-specific protein 1 (FSP1). FSP1 and α-SMA expressions were detected by RT-PCR and Western blot analysis. EndMT was also studied in human aortic endothelial cells (HAECs) that had been exposed to high glucose (HG) levels.

RESULTS

Increased interstitial fibrosis was detected in the DM group. Double labeling revealed CD31 expression in FSP1-positive cells in the DM group, and this expression was diminished by Irb treatment (P<0.05). In vitro, we found that HG stimulated angiotensin II synthesis in HAECs. When HAECs were exposed to HG, some of the cells acquired a spindle-shaped morphology and demonstrated a loss of CD31 labeling, which was attenuated by Irb treatment. FSP1 and α-SMA mRNA and protein expression levels were markedly upregulated in diabetic rats compared to controls, and their expressions were inhibited by Irb treatment (P<0.05).

CONCLUSION

The results provide the novel insight that an angiotensin II receptor blocker might prevent diabetic cardiomyopathy by abrogating EndMT in diabetic rats.

Long-term use and tolerability of irbesartan for control of hypertension

In this review, we discuss the pharmacological and clinical properties of irbesartan, a noncompetitive angiotensin II receptor type 1 antagonist, successfully used for more than a decade in the treatment of essential hypertension. Irbesartan exerts its antihypertensive effect through an inhibitory effect on the pressure response to angiotensin II. Irbesartan 150-300 mg once daily confers a lasting effect over 24 hours, and its antihypertensive efficacy is further enhanced by the coadministration of hydrochlorothiazide. Additionally and partially beyond its blood pressure-lowering effect, irbesartan reduces left ventricular hypertrophy, favors right atrial remodeling in atrial fibrillation, and increases the likelihood of maintenance of sinus rhythm after cardioversion in atrial fibrillation. In addition, the renoprotective effects of irbesartan are well documented in the early and later stages of renal disease in type 2 diabetics. Furthermore, both the therapeutic effectiveness and the placebo-like side effect profile contribute to a high adherence rate to the drug. Currently, irbesartan in monotherapy or combination therapy with hydrochlorothiazide represent a rationale pharmacologic approach for arterial hypertension and early-stage and late-stage diabetic nephropathy in hypertensive type II diabetics.

Angiotensin II mediates the high-glucose-induced endothelial-to-mesenchymal transition in human aortic endothelial cells

Background

Substantial evidence suggests that high glucose (HG) causes endothelial cell damage; however, the potential mechanism therein has yet to be clarified. The aim of this study was to investigate the influence of HG on the endothelial-to-mesenchymal transition (EndMT) and its relevance to the activation of the renin-angiotensin system.

Methods

Primary human aortic endothelial cells (HAECs) were divided into three groups: a normal glucose (NG) group, HG group, and irbesartan (1 μM)-treated (HG+irbesartan) group. The concentration of angiotensin II in the supernatant was detected by radioimmunoassay. Pathological changes were investigated using fluorescence microscopy and electron microscopy. Immunofluorescence staining was performed to detect the co-expression of CD31 and fibroblast markers, such as fibroblast-specific protein 1 (FSP1). The expressions of FSP1 and α-SMA were detected by RT-PCR and Western blot.

Results

The treatment of HAECs in the HG group resulted in significant increases in the expressions of FSP1 and angiotensin II in dose-and time-dependent manners. The incubation of HAECs exposure to HG resulted in a fibroblast-like phenotype, wherein increased microfilamentation and a roughened endoplasmic reticulum structure were observed in the cytoplasm. The expressions of FSP1 and α-SMA were significantly increased in the HG group, and these changes were inhibited by irbesartan treatment (P < 0.05). Double staining of the HAECs indicated a co-localization of CD31 and FSP1 and that some cells acquired spindle-shaped morphologies and a loss of CD31 staining; however, treatment with irbesartan attenuated the expression of EndMT (P < 0.05).

Conclusions

These findings suggest a novel mechanism in HG-induced endothelial damage via the mediation of the EndMT by angiotensin II, which was inhibited by Irbesartan.