Nitrosamines (NAs) are potent genotoxic agents (GAs) in several animal species, and some are classified as probable or possible human carcinogens by the International Agency for Research on Cancer (IARC). In July 2018, angiotensin II receptor blockers (ARBs) which are used to treat high blood pressure have been recalled owing to contamination with NAs. In this study, a simple and sensitive method for the determination of eleven NAs in a single analysis was developed, using atmospheric pressure chemical ionisation source coupled liquid chromatography tandem mass spectrometer (LC-APCI-MS/MS). By performing the 17 min-run in dynamic multiple reaction monitoring (dMRM) mode, eleven NAs were separated on a Poroshell HPH C18 (4.6 × 150 mm, 2.7 µm) column with gradient elution implementing mobile phase A consisting of 0.2 % formic acid in water and mobile phase B consisting of methanol. The developed analytical method was successfully applied in both active pharmaceutical ingredients (APIs) and finished products (FPs) of valsartan and irbesartan with straightforward and effective extraction procedures. Good linearity with a correlation coefficient (R2) > 0.996 was achieved over the concentration in a range of 0.5-50 ng/mL. The limits of detection (LODs) ranged in 0.001-0.008 ppm and limits of quantitation (LOQs) ranged in 0.008-0.05 ppm of the method fulfilled thresholds of US Food and Drug Administration (US-FDA) and European Medicines Agency (EMA) for testing of GAs in valsartan and irbesartan. The accuracy of the proposed method ranged from 73.1 % to 115.2 % for APIs and the relative standard deviation (RSD %) was ≤11.3 while these validation parameters were in the range of 80.2-128.5 % and ≤ 10.6 for FPs, respectively.

N-nitrosamines (NA) impurities have unexpectedly been found in sartan products, angiotensin II receptor antagonists that are used to control hypertension, representing an urgent concern for industry, global regulators and for the patients. In this study, an HPLC-MS/MS method was developed and validated for the quantification of six NA (N-nitrosodimethylamine, N-Nitroso-N-methyl-4-aminobutyric acid, N-Nitrosodiethylamine, N-ethyl-N-nitroso-2-propanamine, N-nitroso-diisopropylamine and N-nitroso-di-n-butylamine) in losartan, valsartan, olmesartan, irbesartan, candesartan and telmisartan products. The method was validated in terms of sensitivity, linearity, accuracy, precision, robustness and stability. The limits of quantification were 100, 31.25, 250, 33, 312.5 and 125 µg kg-1 in losartan, valsartan, olmesartan, irbesartan, candesartan and telmisartan samples, respectively, which met the sensitivity requirements for the limits set by Food and Drug Administration of the United States. The standard curves showed good linearity. The recoveries ranged from 93.06 to 102.23% in losartan matrix, 83 to 85.9% in valsartan, 96.1 to 101.2% in olmesartan, 89.2 to 97.5% in irbesartan, 93.4 to 132.0% in candesartan and 62.3 to 106.2% in telmisartan matrix. The other parameters met the validation criteria, the good sensitivity and precision, high accuracy and simple and fast analysis provides a reliable method for quality control of NA in sartan pharmaceutical products. The developed method was successfully applied for the determination of N-nitrosamines in 71 sartan products marketed in Brazil.

This study aimed to probe the effects of low-dose irbesartan and hydrochlorothiazide in combination with levamlodipine at different times on the circadian rhythm of blood pressure, matrix metalloproteinases (MMPs), and tissue inhibitors of metalloproteinases (TIMPs) levels in patients with non-dipper hypertension (NDH). In this prospective randomized controlled trial, 124 patients with NDH who visited our hospital between August 2018 and July 2021 were enrolled and divided into morning (62 patients) and night (62 patients) medication groups according to the random number table method. All patients received low-dose irbesartan and hydrochlorothiazide combined with levamlodipine, with the morning medication group taking the medication between 7:00 and 10:00 and the night medication group taking the medication between 19:00 and 22:00 for 24 weeks. The effect of antihypertensive medication in both groups was measured, and changes in ambulatory blood pressure, blood pressure circadian rhythm, left ventricular structure, vascular endothelial function, MMPs, and TIMPs levels were observed before treatment initiation and after 24 weeks of treatment in both groups. The percentage of the dipper type was higher in the night medication group than in the morning medication group, while the percentage of the non-dipper type was lower in the morning medication group (p < .05). Low-dose irbesartan and hydrochlorothiazide combined with levamlodipine at different times can effectively treat NDH, but bedtime dosing is more beneficial in reducing nocturnal blood pressure, reversing NDH, improving the circadian rhythm of blood pressure, left ventricular structure, regulating vascular endothelial function, increasing MMPs levels, and reducing TIMP levels.

Background: Irbesartan (IR) is used in the treatment of hypertension, heart failure, and nephropathy in Type II diabetes. IR bioavailability is limited by poor solubility and presystemic metabolism. In our previous investigations, cyclodextrin (HPβCD) complexed solid lipid nanoparticles (SLNs) of IR were prepared, optimized, and characterized. The current study aimed to confirm the reproducibility of the previous methodology and to evaluate the pharmacokinetic (PK) and pharmacodynamic (PD) performance of the selected lead formulations in an experimental animal model. Methods: SLNs were prepared by hot homogenization followed by probe sonication with IR/HPβCD inclusion complex loaded into a solid lipid (Dynasan 112). SLNs were evaluated for physical characteristics, drug content, entrapment efficiency, in vitro release profile, and surface morphology. The pharmacokinetic and pharmacodynamic behavior of the SLNs were evaluated in Wistar rats. Results: Photon correlation spectroscopy, drug content, entrapment efficiency, and dissolution studies results were reproducible and consistent with our earlier investigation. PK studies showed 2.1-, 6.6-, and 9.9-fold improvement in the relative oral bioavailability of the drug from IR-HPβCD, IR-SLN, and IR-HPβCD-SLN formulations, respectively compared to IR suspension. However, IR-HPβCD-SLNs showed 1.5- and 4.7-fold improvement in the relative oral bioavailability of the drug compared to IR-SLN and IR-HPβCD formulations, respectively. PD studies in hypertensive Wistar rats showed a good control over systolic blood pressure for 48 h for SLN formulations compared to 2 h for IR suspension. However, the IR-HPβCD inclusion complex exhibited immediate antihypertensive activity (0.5 h) with a period of systolic blood pressure control similar to IR suspension. Conclusions: The current approach exhibited improved oral bioavailability along with improved and prolonged pharmacodynamic effect.

In recent years, polymorphic transformation involved in media milling has become a key factor in inducing the instability of nanosuspensions (NSs). The variation trend of microhydrodynamic parameters, including milling intensity factor (F), can be observed under different milling conditions. Therefore, this study first referenced the microhydrodynamic model to explore how formulations and process parameters affect Irbesartan (IRB) form A crystallinity during wet media milling. As a result, the crystallinity of form A was affected by the intermolecular interactions between drug particles and stabilizers. The crystallinity of form A decreased with decreasing drug loading, increasing stirrer speed and bead loading, which depended on the role of F. Milling could promote the transformation from a 1H to 2H tetrazole ring with stabilizers containing -OH, and form B was changed to form A and finally to an amorphous state. Molecular modelling shows that forms A and B are ductile and fragile materials, respectively, and both present anisotropy. When milling beads hit both polymorphs paralleling to the (010) surface, the bead-bead collisions are more helpful in fracturing IRB particles. The results of this study may provide a foundation for controlling crystal transformation and obtaining ideal crystal forms.

Micropollutants (MPs), such as pharmaceuticals and antibiotics, are present in the environment at low concentrations (ng/L-μg/L). A constructed wetland (CW) is a nature-based wastewater treatment technology, which can be used to remove MPs from wastewater treatment plant effluent. This study aimed to improve MP removal of CWs by optimizing the design of batch-operated CW. Three pilot-scale CWs were built to study the effect of two design-features: the use of a support matrix (a mixture of bark and biochar) and continuous aeration. The use of bark-biochar as support matrix increased the removal of 11 of 12 studied MPs compared to the CW filled with conventional material sand. The highest improved removal by the addition of bark-biochar was more than 40% (median) for irbesartan, carbamazepine, hydrochlorothiazide and benzotriazole. Aerating the bed of the bark-biochar CW did not change MP removal. Besides, the presence of bark-biochar also enhanced the removal of total nitrogen during 10 months of operation, but no improvement was observed on the total organic carbon and total phosphorus removal. Considering the application in a batch-operated CW, MP removal can be greatly enhanced by replacing sand with bark-biochar that will act as MP adsorbing matrix.

Starting in July 2018, the FDA alerted patients and health care professionals to the recall of ARBs such as valsartan by several pharmaceutical companies because of their potential contamination with carcinogenic nitrosamine impurities, including: (1) N-nitrosodimethylamine (NDMA), (2) N-nitrosodiethylamine (NDEA), (3) N-nitrosoethylisopropylamine (NEIPA), (4) N-nitrosodiisopropylamine (NDIPA), (5) N-nitrosodibutylamine (NDBA) and (6) N-nitroso-N-methyl-4-aminobutyric acid (NMBA). The FDA initiated a laboratory investigation to develop analytical procedures to test multiple lots of marketed ARB drugs to determine the possible presence of carcinogenic impurities and, if present, quantitate the levels of these impurities. Here the FDA laboratory developed and validated an automated micro-solid phase extraction MS/MS method, where all the analytes are not separated prior to elution to the MS, to simultaneously quantify NEIPA, NDIPA, NDBA and NMBA in ARB drug substances with an instrument sample analysis time of 12 seconds. The method was validated according to the ICH Q2(R1) guideline, and was determined to be specific, accurate, precise and linear over the corresponding nitrosamine analytical ranges. The method has been successfully implemented to quantitate the four nitrosamine impurities in 129 generic losartan, valsartan, olmesartan, irbesartan and telmisartan drug substance samples from 32 lots; and 32 losartan and valsartan drug product samples from 6 lots.

Nitrosamines are carcinogens substances firstly detected in sartans drugs in 2018, leading to new regulations and monitoring programmes that raised the costs and challenges to the pharmaceutical industry. Therefore, reliable and cost-effective methods for screening nitrosamines in medicines are highly desirable. Hydrophobic deep eutectic solvents (HDES), a novel "eco-friendly" alternative to solvents commonly used in microextraction techniques, can meet these requirements. In this study, a simple and rapid method of ultrasound-assisted dispersive liquid-liquid microextraction using thymol-based HDES followed by HPLC-DAD detection was developed for the determination of n-nitrosodimethylamine (NDMA) and n-nitroso-n-methylamino butyric acid (NMBA) from candesartan, irbesartan, losartan, olmesartan, telmisartan and valsartan drug substances, and from losartan tablets. Various influencing factors (such as HDES type, HDES:sample ratio, salt addition and sample pH) were investigated. Best extraction efficiencies were achieved with thymol:benzyl alcohol HDES. Under optimal conditions, the linearities ranged from 15 to 1000 ng mL-1 for both NDMA and NMBA (R² > 0.99), with recoveries between 81.8-104.2% and precision from 0.2 to 14.6%. The limits of detection were 17.3 - 220.0 ng g-1 and 16.3 - 290.0 ng g-1 for NDMA and NMBA, consecutively. Finally, the proposed method was successfully applied in spiked sartans drug substances and in losartan potassium tablets collected in the market.

Sartans are a group of pharmaceuticals widely used to regulate blood pressure. Their concentration levels were monitored in 80 wastewater treatment plants (WWTP) in the Baltic Sea Region, reached from limit of detection up to 6 µg/L. The concentrations were significantly different in different countries, but consistent within the respective country. The degradation of sartans (losartan, valsartan, irbesartan) in moving bed biofilm reactors (MBBRs) that utilize biofilms grown on mobile carriers to treat wastewater was investigated for the first time, and compared with the degradation in a conventional activated sludge (CAS) treatment plant. The results showed the formation of six microbial transformation products (TPs) of losartan, four of valsartan, and four of irbesartan in biological wastewater treatment. Four of these metabolites have not been described in the literature before. Chemical structures were suggested and selected TPs were verified and quantified depending on availability of true standards. Valsartan acid was a common TP of losartan, valsartan, and irbesartan. Losartan and irbesartan also shared one TP: losartan/irbesartan TP335. Based on the mass balance analysis, losartan carboxylic acid is the main TP of losartan, and valsartan acid is the main TP of valsartan during the biotransformation process. For irbesartan, TP447 is likely to be the main TP, as its peak areas were two orders of magnitude higher than those of all the other detected TPs of this compound. The effects of adapting biofilms to different biological oxygen demand (BOD) loading on the degradation of sartans as well as the formation of their TPs were investigated. Compared to feeding a poor substrate (pure effluent wastewater from a CAS), feeding with richer substrate (1/3 raw and 2/3 effluent wastewater) promoted the metabolism of most compounds (co-metabolization). However, the addition of raw wastewater inhibited some metabolic pathways of other compounds, such as from losartan/irbesartan to TP335 (competitive inhibition). The formation of irbesartan TP447 did not change with or without raw wastewater. Finally, the sartans and their TPs were investigated in a full-scale CAS wastewater treatment plant (WWTP). The removal of losartan, valsartan, and irbesartan ranged from 3.0 % to 72% and some of the transformation products (TPs) from human metabolism were also removed in the WWTP. However, some of the sartan TPs, i.e., valsartan acid, losartan carboxylic acid, irbesartan TP443 and losartan TP453, were formed in the WWTP. Relative high amounts of especially losartan carboxylic acid, which was detected with concentrations up to 2.27 µg/L were found in the effluent.

There is increasing awareness of seasonal variation in blood pressure (BP). In the present analysis, we investigated seasonal variation in the antihypertensive treatment effect of the irbesartan/hydrochlorothiazide combination in patients with stage 2 and 3 hypertension. The study participants were hypertensive patients enrolled in a 12-week therapeutic study. Antihypertensive treatment was initiated with irbesartan/hydrochlorothiazide 150/12.5 mg/day, with possible uptitration to 300/12.5 mg/day and 300/25 mg/day at 4 and 8 weeks of follow-up, respectively. The month of treatment commencement was classified as spring/summer (May to August) and autumn/winter (September to December). Of the 501 enrolled patients, 313 and 188 commenced antihypertensive treatment in spring/summer and autumn/winter, respectively. The mean changes in systolic/diastolic BP at 8 and 12 weeks of follow-up were greater in patients who commenced treatment in autumn/winter (-32.3/-16.5 and -34.2/-16.7 mmHg, respectively) than those who commenced treatment in spring/summer (-28.4/-13.9 and -27.1/-12.8 mmHg, respectively), with a between-season difference of 3.9 (95% confidence interval [CI], 1.4-6.4, P = 0.002)/2.6 (95% CI, 0.9-4.2, P = 0.002) mmHg and 7.0 (95% CI, 4.7-9.3, P < 0.0001)/3.9 (95% CI, 2.4-5.4, P < 0.0001) mmHg, respectively. Further subgroup analyses according to several baseline characteristics showed a greater between-season difference in the changes in systolic BP in patients aged ≥55 years than in those <55 years (n = 255, 12.6 mmHg vs. n = 246, 6.9 mmHg, P = 0.02), especially in patients who did not use antihypertensive medication at baseline (n = 94, 15.4 mmHg vs. n = 132, 5.4 mmHg, P = 0.006). In conclusion, there is indeed seasonality in the antihypertensive treatment effect, with a greater BP reduction in patients who commenced treatment in cold than warm seasons.

The interindividual heterogeneity in response to the antihypertensive effect of irbesartan has received considerable attention because of gene polymorphism. In this study, we investigated the new combinational influences of AGTR1 and ABCB1 gene polymorphism on the therapeutic effect of irbesartan among Chinese hypertensive patients. A total of 353 samples including 168 normal people and 185 hypertensive patients were adopted, and genotypes comprise ABCB1 (CC, CT, and TT) and AGTR1 (AA and AC) in this study. The results of multiple linear regression models showed that no statistically significant differences were observed in blood pressure change following irbesartan administration in each genotype from either ABCB1 (CC, CT, and TT) or AGTR1 (AA and AC). However, spline smoothing analysis demonstrated that the blood pressure therapeutic responses of irbesartan presented a noticeable difference among different ABCB1 genotypes when irbesartan doses reached over 300 ng/mL. Eventually, we assumed that the different drug responses of irbesartan among various AGTR1 genotypes were due to the diversity of the irbesartan-conjugated protein, which is responsible for crossing-coupled intracellular G-protein-coupled receptors (GPCRs).

Stimulation of angiotensin II receptor (ATR) with angiotensin II (Ang II) accelerates cardiac fibroblast activation, resulting in upregulation of cytokines and growth factors. Growth factors were strongly upregulated in animal models of myocardial fibrosis and hypertrophy as well as patients with heart failure. Nevertheless, the signal transduction of ATR for upregulation of growth factors in human cardiac fibroblasts contributing to myocyte hypertrophy have not fully understood. Long-term Ang II treatment of human cardiac fibroblasts provokes the synthesis and secretion of connective tissue growth factor (CTGF), transforming growth factor beta1 (TGF-β1), and vascular endothelial growth factor (VEGF) through the AT1R subtype. Blockade of Gαq, not Gαi or Gα12/13, protein signaling inhibited AT1R-mediated upregulation of CTGF, TGF-β1, and VEGF. In addition, AT1R overstimulation induced upregulation of growth factors via the TGF-β-dependent and ERK1/2-dependent pathways. Growth factors secreted from cardiac fibroblasts are necessary for the induction of hypertrophic markers, atrial natriuretic peptide (ANP) and β-myosin heavy chain (β-MHC), resulting in myocyte hypertrophy. Candesartan, irbesartan, and valsartan had greater effects than losartan for blockade of fibrotic and hypertrophic effects of Ang II. Our data support the concept whereby sustained AT1R stimulation contributes to the development of myocardial fibrosis and hypertrophy, and advances understanding of this complex AT1R signaling, including fibroblasts-myocytes communication during pathological conditions.

The purpose of this study is to improve the solubility and dissolution of a poorly soluble drug, Irbesartan, using solid dispersion techniques. For that purpose, different polymers such as Soluplus®, Kollidon® VA 64, Kolliphor® P 407, and Polyinylpyrrolidone (PVP-K30) were used as carriers at different concentrations to prepare solid dispersion formulations through the solvent evaporation method. In order to prepare binary dispersion formulations, Soluplus® and Kollidon® VA 64 were used at drug: polymer ratios of 1:1, 1:2, 1:3, and 1:4 (w/w). Saturation solubility of the drug in the presence of used carriers was performed to investigate the quantitative increase in solubility. Dissolution studies were performed to explore the drug release behavior from the prepared dispersions. Additionally, the characterization of the prepared formulations was carried out by performing DSC, SEM, XRD, and FTIR studies. The results revealed that among binary systems, K4 formulation (Drug: Kollidon® VA 64 at ratio of 1:4 w/w) exhibited optimal performance in terms of increased solubility, drug release, and other investigated parameters. Furthermore, ternary dispersion formulations of the optimized binary formulation were prepared with two more polymers, Kolliphor® P 407 and Polyvinylpyrrolidone (PVP-K30), at (Drug: Kollidon® VA 64:ternary polymer) ratios of 1:4:1, 1:4:2, and 1:4:3 (w/w). The results showed that KPVP (TD3) exhibited the highest increase in solubility, as well as dissolution rate, among ternary solid dispersion formulations. Results of solubility enhancement by ternary solid dispersion formulations were also supported by FTIR, DSC, XRD, and SEM analysis. Conclusively, it was found that the ternary solid dispersion-based systems were more effective compared to the binary combinations in improving solubility as well as dissolution of a poorly soluble drug (Irbesartan).

During integration to the solid surface, the effects of tags introduced for bioorthogonal reactions on protein activity have received far less investigation. This represents the major challenge of improving the performance of the immobilized protein-based assays. Herein, the relationship between the fusion tags and their reaction efficiency in mediating the assay performance was realized by determining the chromatographic performance using genetically encoded azide-alkyne cycloaddition, and Halo- and SNAP-tagged bioorthogonal reactions for synthesizing immobilized angiotensin II type 1 receptor (AT1R). We demonstrated that immobilization with the incorporation of unnatural amino acid in the receptor minimizes the peak tailings and broadenings of irbesartan, fimasartan, losartan, and tasosartan, while attachment via large tags (SNAP and Halo) leads to serious asymmetry peaks. Upon the first immobilization, the association constants of the four drugs to AT1R appeared to be 1 order of magnitude greater than the other two attachments. Such enhancement is likely reasoned by the improved association rate constants and the relatively identical dissociation rates due to the small tag. While demonstrating improved chromatographic performance, the immobilized AT1R prepared by the genetically encoded azide-alkyne reaction was applied in analyzing Uncaria Schreber nom. cons. extract, which identified hynchophylline as a specific ligand binding to the receptor. As immobilized proteins move toward diverse assays, our findings provide an unprecedented insight into the relation between fusion tags and their reaction efficiency in mediating the assay performance, which is thus dedicated to the creation of a protein-functionalized surface for precisely determining the drug-protein interaction and discovering the specific partner of the protein.

Background: Diabetic nephropathy (DN) is one of the most common and serious chronic complications in the clinic. Cornus officinalis has the effects of replenishing qi and nourishing yin, tonifying liver and kidney, and it is one of the main traditional Chinese medicines used clinically to treat diabetes and its complications. However, the effect and mechanism of Cornus officinalis before and after processing on intestinal flora of diabetic nephropathy need to be further elucidated. Methods: SD rats were randomly divided into a blank group (10 rats) and DN groups (70 rats). After 4 weeks of high-sugar and high-fat diet, the DN rat model was established by intraperitoneal injection of streptozotocin. After successful modeling, the rats were randomly divided into DN model group, irbesartan group (1.35 mg·kg-1), Cornus officinalis group (281.25 mg·kg-1), wine Cornus officinalis group (281.25 mg·kg-1), wine honey Cornus officinalis group (281.25 mg·kg-1), auxiliary wine group (10 ml·kg-1), auxiliary wine honey group (10 ml·kg-1). During the observation of the rats' general state, after 6 weeks of continuous administration, the fasting blood glucose of rats in each group was detected, and the kidney index was calculated. The serum creatinine levels, urea nitrogen and 24 h urinary microalbumin were detected by enzyme-linked immunosorbent assay. The expression levels of YKL-40, Wnt4, β-catenin and TGF-β 1 mRNA in renal tissue were detected by fluorescence quantitative PCR. Hematoxylin-eosin staining was used to observe the changes in renal pathological injury in each group; GC-MS detected the changes of short chain fatty acid content. Feces were collected for 16 s high-throughput sequencing to analyze the effects of Cornus officinalis on the diversity of intestinal flora in DN before and after processing. Results: Compared with the blank group, the serum creatinine, urea nitrogen, 24 h urinary microalbumin, kidney index and fasting blood glucose in the DN model group were significantly increased (p < 0.05). The renal tissue morphology was disordered and a large number of inflammatory cells were infiltrated. The expression of YKL-40, Wnt4, β-catenin and TGF-β 1 mRNA was significantly increased (p < 0.05). Compared with the DN model group, the serum creatinine, urea. Nitrogen, 24 h urine microalbumin, kidney index and fasting blood glucose of rats in each administration group were significantly decreased (p < 0.05), and the general condition and pathological renal damage of DN rats were improved. The effect of wine honey Cornus officinalis was the best, and the expression of YKL-40, Wnt4, β-catenin and TGF-β 1 mRNA was significantly decreased (p < 0.05). In each administration group, the improvement of the above indicators in the wine honey Cornus officinalis group was significantly better than that in the raw Cornus officinalis group and wine Cornus officinalis group (p < 0.05), There was no significant difference compared with the irbesartan group (p > 0.05). Each administration group had a significant callback effect on the content of short-chain fatty acids in rat feces, with increased intestinal beneficial bacteria and decreased pathogenic bacteria. Compared with the blank group, the abundance of Firmicutes in the DN model group increased, the abundance of Bacteroidetes decreased, and the ratio showed an upward trend in the DN model group decreased. Each administration group could improve the relative abundance of the above intestinal flora in the model group to varying degrees. Conclusion: The processing of Cornus officinalis may improve the renal injury of DN rats by blocking the activation of Wnt/β-catenin signaling pathway, regulating the structural composition of intestinal microorganisms, and ultimately playing a role in renal protection.

Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) is a rapid and low-solvent-consumption technique. However, almost every mass in the low mass-to-charge-ratio region of the mass spectrum appears as strongly fluctuating matrix background signals. Thus, it is difficult to identify small molecules using this technique. In this study, we used methanol to methylate valsartan, an angiotensin II receptor blocker that is commonly used to treat high blood pressure and heart failure. The methylation derivatization of valsartan enhanced the detection sensitivity and transformed the detection m/z ratio. The liquid-phase microextraction of valsartan in human plasma (20 μL) was achieved by acidifying valsartan with HCl aqueous solution and extracting it with toluene. An acetyl chloride/anhydrous methanol mixture was added for methylation derivatization, which was completed within 30 min at 30 °C. Finally, the residue was re-dissolved in irbesartan methanolic solution, which together with the matrix 2-mercaptobenzothiazole was spotted on an AnchorChip target plate for MALDI-TOF MS analysis. Liquid-phase microextraction was performed and the methylation-derivatization parameters were investigated. The valsartan calibration range was 0.2-10 μg mL-1 with good linearity in human plasma. In the within- and between-run analyses, the relative standard deviation and relative error were both <11.32%. This method was successfully applied to determine the valsartan concentration in the plasma of 10 patients with hypertension.

In this paper, a surface-enhanced Raman scattering (SERS) strategy was constructed for the determination of antihypertensive drugs irbesartan (IRB) and doxazosin mesylate (DOX). β-Cyclodextrin-capped silver nanoparticles (CD-AgNPs) are employed as SERS-active substrate. The introduction of β-CD with hydrophobic cavity can capture drug molecules to form host-guest complex, making the drug molecules closer to the electromagnetic enhancement field of the AgNPs, thereby enhancing the SERS signal of drug molecules with low Raman cross-section. The vibrational modes of IRB and DOX are assigned by density functional theory calculations. The linear response from 3.0 × 10-7 to 1.0 × 10-5 mol L-1 for IRB and 3.0 × 10-7 to 2.0 × 10-5 mol L-1 for DOX and low limits of detection (LOD) 7.5 × 10-8 mol L-1 for IRB and 8.6 × 10-8 mol L-1 for DOX can be achieved. Meanwhile, this SERS approach can be applicable to determine IRB and DOX in commercial drug tablets, healthcare products, and human urine samples with recoveries of 90.8-115.7% and 90.0-113.5%, respectively, with relative standard deviation (RSD) less than 4.5%. This designed SERS strategy enables for the rapid determination of IRB and DOX in drug quality monitoring and illegal additives in healthcare products as well as clinical applications.

Pulmonary hypertension (PH) is frequent in the general population and is linked to an increased risk of death. Riociguat is a kind of endothelin receptor antagonist that is often used to treat PH. For pharmacokinetic studies and the determination of riociguat in PH patients, a new, quick, easy, and sensitive UPLC-MS/MS approach was designed and validated. Riociguat and irbesartan (IS) were detected using ESI in positive ion and multiple reaction monitoring mode, respectively, by monitoring the mass transitions m/z 423.0 → 391.0 and 429.1 → 206.9. A reverse-phase C18 column (5 μm, 4.6 × 150 mm) was used with an isocratic mobile phase of water containing 0.1 % formic acid-acetonitrile (25:75, v/v) at a flow rate of 1 ml/min for chromatographic separation. In the range of 5-400 ng/ml, the calibration curve was linear and had a good correlation coefficient (0.9972). This is the first UPLC-MS/MS technique that has been developed and validated for determining riociguat from human plasma. The developed analytical method was extensively validated for linearity, selectivity, specificity, accuracy, precision, sensitivity, stability, matrix effect and recovery, according to FDA criteria. The devised approach was successfully used for a pharmacokinetic research and riociguat determination in PH patients.

Arginases are often overexpressed in human diseases, and they are an important target for developing anti-aging and antineoplastic drugs. Arginase type 1 (ARG1) is a cytosolic enzyme, and arginase type 2 (ARG2) is a mitochondrial one. In this study, a dataset containing 2115-FDA-approved drug molecules is virtually screened for potential arginase binding using molecular docking against several ARG1 and ARG2 structures. The potential arginase ligands are classified into three categories: (1) Non-selective, (2) ARG1 selective, and (3) ARG2 selective. The evaluated potential arginase ligands are then compared with their clinical use. Remarkably, half of the top 30 potential drugs are used clinically to lower blood pressure and treat cancer, infection, kidney disease, and Parkinson's disease thus partially validating our virtual screen. Most notable are the antihypertensive drugs candesartan, irbesartan, indapamide, and amiloride, the antiemetic rolapitant, the anti-angina ivabradine, and the antidiabetic metformin which have minimal side effects. The partial validation also favors the idea that the other half of the top 30 potential drugs could be used in therapeutic settings. The three categories greatly expand the selectivity of arginase inhibition.

The presence of contaminants of emerging concern in the aquatic environment directly impacts water-living organisms and can alter their living functions. These compounds are often metabolized and excreted, but they can also be accumulated and spread through the food chain. The metabolized contaminants can also lead to the formation of new compounds with unknown toxicity and bioaccumulation potential. In this work, we have studied the occurrence, bioconcentration, and biotransformation of CECs in glass eels (Anguilla anguilla) using UHPLC-HRMS. To select the target CECs, we first carried out an environmental risk assessment of the WWTP effluent that releases directly into the Adour estuary (Bayonne, Basque Country, France). The risk quotients of every detected contaminant were calculated and three ecotoxicologically relevant contaminants were chosen to perform the exposure experiment: propranolol, diazepam, and irbesartan. An experiment of 14 days consisting of 7 days of exposure and 7 days of depuration was carried out to measure the bioconcentration of the chosen compounds. The quantitative results of the concentrations in glass eel showed that diazepam and irbesartan reached BCF ≈10 on day 7, but both compounds were eliminated after 7 days of depuration. On the other hand, propranolol's concentration remains constant all along with the experiment, and its presence can be detected even in the non-exposed control group, which might suggest environmental contamination. Two additional suspect screening strategies were used to identify metabolization products of the target compounds and other xenobiotics already present in wild glass eels. Only one metabolite was identified, nordiazepam, a well-known diazepam metabolite, probably due to the low metabolic rate of glass eels at this stage. The xenobiotic screening confirmed the presence of more xenobiotics in wild glass eels, prominent among them, the pharmaceuticals exemestane, primidone, iloprost, and norethandrolone.

A sensitive and robust method for determination and quantification of potential genotoxic impurities in sartans has been developed. These impurities need to be controlled at trace levels during quantification in drug substances and drug products for safe consumption. Recent regulatory requirements also suggested the need to have highly sensitive analytical method for trace level quantification of nitrosamine impurities. In this paper, we have described a simple, rapid and sensitive liquid chromatography-mass spectrometry method for six potential genotoxic nitrosamine impurities: N-Nitroso dimethyl amine (NDMA), N-Nitroso diethyl amine (NDEA), N-Nitroso Ethyl Iso propylamine (NIPEA), N-Nitroso-Nmethyl-4-aminobutyric acid (NMBA) N-Nitroso diisopropylamino (NDIPA) and N-Nitroso dibutyl amine (NDBA) in Azilsartan (AZL), Valsartan (VAL), Telmisartan (TEL), Olmesartan (OLM), Losartan (LOS) and Irbesartan (IRB) with a limit of quantification of less than 0.003 ppm. Chromatographic separation is achieved using Poroshell HPH- C18, 150 × 4.6 mm, 2.7 μm column with 0.1% formic acid in water as mobile phase A and 0.1% formic acid in methanol as mobile phase B at a flow rate of 0.5 mL/min using gradient mode of elution at a total run time of 20 min. Six nitrosamine impurities are ionized and quantified in positive mode of atmospheric pressure chemical ionization using multiple reaction monitoring. As per ICH guidelines, method validation is performed and evaluated the limit of quantification and detection and found to give good S/N ratios with good linearity range of 0.003-0.045 ppm with regression coefficient > 0.999 for all the six nitrosamine impurities. Method recoveries are also established using three-step sample preparation and are found to be satisfactory within 80-120%. The single method can be used routinely applied for the detection of nitrosamines in AZL, VAL, TEL, OLM, LOS and IRB.

Mitochondria-mediated apoptosis plays a critical role in myocardial ischemia reperfusion (IR) injury and causes a negative impact on cardiac efficiency and function. The combined angiotensin receptor-neprilysin inhibitor (ARNI) is a promising cardioprotective pharmacological agent that could rescue the heart from IR injury. This study investigated the cardioprotective effect of thiorphan (TH) in combination with three different doses of irbesartan (IRB) on myocardial IR injury and detected the most effective dose combination. Male Wistar rats were used and divided into five groups (10 rats/group): (I) Sham, (II) ischemia-reperfusion I/R, (III) TH/IRB + IR (0.1/5 mg/kg), (IV) TH/IRB + IR (0.1/10 mg/kg), and (V) TH/IRB + IR (0.1/15 mg/kg) groups. Thiorphan and irbesartan were injected intraperitoneally 15 min before IR induction. Mean arterial blood pressure, left ventricular end diastolic pressure (LVEDP), left ventricular maximum rate of pressure (LVdp/dtmax), and cardiac levels of creatine kinase-MB, malondialdehyde, superoxide dismutase, and endothelin-1 were measured. Cardiac mitochondria complexes activities, histopathological examination of myocardial tissues, immunohistochemistry studies for myocardial apoptosis (Bax and Bcl-2), and electron microscopy examination of left ventricle were performed. TH/IRB combination preserved cardiac functions and mitochondria complex activities and mitigated cardiac damage, oxidative stress, and apoptosis following IR. Also, there was an evident improvement in histopathological changes and electron microscopy examination of left ventricle compared with I/R group. TH/IRB in a dose of 0.1/10 mg/kg showed significant improvement compared with the other treated groups. Thiorphan/irbesartan improved cardiac functions following IR injury. This could be explained by the reported improvement of mitochondria complex activities and reduction of oxidative stress, endothelin-1, and apoptosis.

Methylglyoxal (MGO) is predominantly produced as a by-product of the glycolysis pathway. The glyoxalase system effectively removes it in a healthy organism. However, this process is impaired, and MGO level is elevated in people with diabetes. MGO's effects on proliferation were mostly studied in cancer cells, and the data in other cell types are limited. This study inspected the proliferative capacity of MGO in vascular smooth muscle cells (VSMCs), which have a crucial role in atherosclerosis and restenosis. The roles of ERK1/2 MAPK and Akt phosphorylations in proliferation were determined. Telmisartan, irbesartan, and NF-κB inhibitor JSH-23's roles in protecting the cells from MGO-induced proliferation were also investigated. Primary VSMCs were isolated from the rat aorta. The proliferation was spectrophotometrically measured by using a tetrazolium salt (Wst-1). The cells were cultured in standard media (SM, glucose conc. 5.5 mM) or high glucose media (HGM, glucose conc. 25 mM; an in vitro model of hyperglycemia). ERK1/2 MAPK and Akt phosphorylations were determined by the western blot method. MGO triggered the proliferation at 24, 48, and 72 hrs in SM and 48 and 72 hrs in HGM. Low doses of MGO such as 1-10 µM can induce proliferation. The phosphorylated ERK1/2 MAPK and Akt participated in MGO-induced proliferation. Telmisartan, irbesartan, and JSH-23 effectively alleviated the proliferation and Akt phosphorylation. MGO could proliferate VSMCs even at low doses. Moreover, hypertensive diabetic patients might benefit from a sartan family drug to protect VSMCs from MGO-induced proliferation.