Existence of Quantum Pharmacology in Sartans: Evidence in Isolated Rabbit Iliac Arteries

Quantum pharmacology introduces theoretical models to describe the possibility of ultra-high dilutions to produce biological effects, which may help to explain the placebo effect observed in hypertensive clinical trials. To determine this within physiology and to evaluate novel ARBs, we tested the ability of known angiotensin II receptor blockers (ARBs) (candesartan and telmisartan) used to treat hypertension and other cardiovascular diseases, as well as novel ARBs (benzimidazole-N-biphenyl tetrazole (ACC519T), benzimidazole-bis-N,N'-biphenyl tetrazole (ACC519T(2)) and 4-butyl-N,N0-bis[[20-2Htetrazol-5-yl)biphenyl-4-yl]methyl)imidazolium bromide (BV6(K+)2), and nirmatrelvir (the active ingredient in Paxlovid) to modulate vascular contraction in iliac rings from healthy male New Zealand White rabbits in responses to various vasopressors (angiotensin A, angiotensin II and phenylephrine). Additionally, the hemodynamic effect of ACC519T and telmisartan on mean arterial pressure in conscious rabbits was determined, while the ex vivo ability of BV6(K+)2 to activate angiotensin-converting enzyme-2 (ACE2) was also investigated. We show that commercially available and novel ARBs can modulate contraction responses at ultra-high dilutions to different vasopressors. ACC519T produced a dose-dependent reduction in rabbit mean arterial pressure while BV6(K+)2 significantly increased ACE2 metabolism. The ability of ARBs to inhibit contraction responses even at ultra-low concentrations provides evidence of the existence of quantum pharmacology. Furthermore, the ability of ACC519T and BV6(K+)2 to modulate blood pressure and ACE2 activity, respectively, indicates their therapeutic potential against hypertension.

Uptake and metabolization of four sartan drugs by eight different plants: Targeted and untargeted analyses by HPLC-drift-tube-ion-mobility quadrupole time-of-flight mass spectrometry

In this study, we investigated the uptake and metabolization of four drugs (plus the associated prodrugs) from the sartan family by eight edible plants. Growing the plants hydroponically in a medium containing the respective drug, more than 40 phases I and II metabolites derived from the four sartan drugs could be tentatively identified. To demonstrate the suitability of the proposed analytical approach for actual environmental samples, garden cress (Lepidium sativum) selected as a model plant was grown in water drawn from the effluent of two local wastewater treatment plants. Thereby, three of the sartans, namely, olmesartan, candesartan, and valsartan, could be found in the plant extracts at concentrations of 3.1, 10.4, and 14.4 ng g-1 , respectively. Additionally, for candesartan and valsartan, a glycosylated transformation product could be detected. In order to extend the present (targeted) workflow also toward the analysis of unknown transformation products (i.e., those not listed in the custom-made database used for this research), a nontargeted approach for the analysis of plant extracts with respect to the presence of drug-related metabolites was developed. Comparison of the targeted and the nontargeted workflows led to the finding of two additional, so far unidentified, transformation products originating from azilsartan.

An Overview and Discussion of N-nitrosamine Considerations for Orally Inhaled Drug Products and Relevance to Other Dosage Forms

The presence of N-nitrosamines in drug products are currently an area of high regulatory and industry scrutiny, having been detected above acceptable regulatory levels in several solid oral drug products. For over 20 years, there has been an expectation that N-nitrosamines be eliminated or controlled to acceptable levels in orally inhaled and nasal drug products (OINDP). As a result, the OINDP industry has developed and implemented risk management processes and considerations to address N-nitrosamines in final drug product, including management and understanding of upstream supply particularly for OINDP device and container closure systems. We provide an overview of N-nitrosamine formation, discuss key current regulatory expectations worldwide for N-nitrosamines in drug products, discuss risk management approaches relevant for drug device combination products, and share analytical "tips" with respect to handling N-nitrosamines chemical assessments.

In the prevention of dementia, the focus should be on early and consistent treatment of hypertension

The brain is among the target organs of hypertension. Patients with hypertension have a higher risk of developing stroke as well as experiencing a decline in cognitive functions and dementia. Changes in the white matter and atrophy of the grey matter of the brain induced by high blood pressure develop insidiously since the onset of hypertension, even in young individuals. The effect of high blood pressure on the vessel wall cumulates in time; therefore, hypertension in younger people implies an increased risk of dementia in older age. Hypertension in young age cannot be considered a benign condition. Hypertension in middle age increases the risk of dementia by 61 %. Consistent and early hypertension control can reverse the adverse development towards dementia and lack of self-sufficiency in the patient. Data comparing individual antihypertensive drugs in terms of preventing dementia are scarce. However, renin angiotensin system blockers have been found to protect against Alzheimer's disease more than other classes of antihypertensive drugs. To achieve rapid and effective hypertension control, a combination of antihypertensive drugs is usually required. Using a fixed-dose triple combination of perindopril, indapamide, and amlodipine, blood pressure targets of < 130/80 mm Hg can be achieved within three months in 93 % of patients.

Actions of Novel Angiotensin Receptor Blocking Drugs, Bisartans, Relevant for COVID-19 Therapy: Biased Agonism at Angiotensin Receptors and the Beneficial Effects of Neprilysin in the Renin Angiotensin System

Angiotensin receptor blockers (ARBs) used in the treatment of hypertension and potentially in SARS-CoV-2 infection exhibit inverse agonist effects at angiotensin AR1 receptors, suggesting the receptor may have evolved to accommodate naturally occurring angiotensin ‘antipeptides’. Screening of the human genome has identified a peptide (EGVYVHPV) encoded by mRNA, complementary to that encoding ANG II itself, which is an inverse agonist. Thus, opposite strands of DNA encode peptides with opposite effects at AR1 receptors. Agonism and inverse agonism at AR1 receptors can be explained by a receptor ‘switching’ between an activated state invoking receptor dimerization/G protein coupling and an inverse agonist state mediated by an alternative/second messenger that is slow to reverse. Both receptor states appear to be driven by the formation of the ANG II charge-relay system involving TyrOH-His/imidazole-Carboxylate (analogous to serine proteases). In this system, tyrosinate species formed are essential for activating AT1 and AT2 receptors. ANGII is also known to bind to the zinc-coordinated metalloprotease angiotensin converting enzyme 2 (ACE2) used by the COVID-19 virus to enter cells. Here we report in silico results demonstrating the binding of a new class of anionic biphenyl-tetrazole sartans (‘Bisartans’) to the active site zinc atom of the endopeptidase Neprilysin (NEP) involved in regulating hypertension, by modulating humoral levels of beneficial vasoactive peptides in the RAS such as vasodilator angiotensin (1–7). In vivo and modeling evidence further suggest Bisartans can inhibit ANG II-induced pulmonary edema and may be useful in combatting SARS-CoV-2 infection by inhibiting ACE2-mediated viral entry to cells.

Diminazene Aceturate Reduces Angiotensin II Constriction and Interacts with the Spike Protein of Severe Acute Respiratory Syndrome Coronavirus 2

Diminazene aceturate (DIZE) is a putative angiotensin-converting enzyme 2 (ACE2) activator and angiotensin type 1 receptor antagonist (AT₁R). Its simple chemical structure possesses a negatively charged triazene segment that is homologous to the tetrazole of angiotensin receptor blockers (ARB), which explains its AT₁R antagonistic activity. Additionally, the activation of ACE2 by DIZE converts the toxic octapeptide angiotensin II (AngII) to the heptapeptides angiotensin 1–7 and alamandine, which promote vasodilation and maintains homeostatic balance. Due to DIZE’s protective cardiovascular and pulmonary effects and its ability to target ACE2 (the predominant receptor utilized by severe acute respiratory syndrome coronavirus 2 to enter host cells), it is a promising treatment for coronavirus 2019 (COVID-19). To determine DIZE’s ability to inhibit AngII constriction, in vitro isometric tension analysis was conducted on rabbit iliac arteries incubated with DIZE or candesartan and constricted with cumulative doses of AngII. In silico docking and ligand interaction studies were performed to investigate potential interactions between DIZE and other ARBs with AT₁R and the spike protein/ACE2 complex. DIZE, similar to the other ARBs investigated, was able to abolish vasoconstriction in response to AngII and exhibited a binding affinity for the spike protein/ACE2 complex (PDB 6LZ6). These results support the potential of DIZE as a treatment for COVID-19.

The EU Response to the Presence of Nitrosamine Impurities in Medicines

The unexpected detection of nitrosamine impurities in human medicines has recently seen global regulators act to understand the risks of these contaminations to patients and to limit their presence. Over 300 nitrosamines are known, many of which are highly potent mutagenic carcinogens. Regulators first became aware of the presence of nitrosamines in EU medicines in 2018, with reports of detection of N-nitroso-dimethylamine (NDMA) in valsartan from one manufacturer. A subsequent EU review of all valsartan medicines was triggered by the European Medicines Agency (EMA) and was later extended to other angiotensin receptor blockers/sartans. A separate review was also started for ranitidine medicines. This was followed by an EU-wide examination of the risk of presence of nitrosamines in all human medicines. This article reflects on the investigation of the EU regulatory network into the presence of nitrosamines and the scientific knowledge informing recommendations for developers on how to limit nitrosamines in medicines.

Preliminary Evidence for IL-10-Induced ACE2 mRNA Expression in Lung-Derived and Endothelial Cells: Implications for SARS-Cov-2 ARDS Pathogenesis

Angiotensin-converting enzyme 2 (ACE2) is a receptor for the spike protein of SARS-COV-2 that allows viral binding and entry and is expressed on the surface of several pulmonary and non-pulmonary cell types, with induction of a “cytokine storm” upon binding. Other cell types present the receptor and can be infected, including cardiac, renal, intestinal, and endothelial cells. High ACE2 levels protect from inflammation. Despite the relevance of ACE2 levels in COVID-19 pathogenesis, experimental studies to comprehensively address the question of ACE2 regulations are still limited. A relevant observation from the clinic is that, besides the pro-inflammatory cytokines, such as IL-6 and IL-1β, the anti-inflammatory cytokine IL-10 is also elevated in worse prognosis patients. This could represent somehow a “danger signal”, an alarmin from the host organism, given the immuno-regulatory properties of the cytokine. Here, we investigated whether IL-10 could increase ACE2 expression in the lung-derived Calu-3 cell line. We provided preliminary evidence of ACE2 mRNA increase in cells of lung origin in vitro, following IL-10 treatment. Endothelial cell infection by SARS-COV-2 is associated with vasculitis, thromboembolism, and disseminated intravascular coagulation. We confirmed ACE2 expression enhancement by IL-10 treatment also on endothelial cells. The sartans (olmesartan and losartan) showed non-statistically significant ACE2 modulation in Calu-3 and endothelial cells, as compared to untreated control cells. We observed that the antidiabetic biguanide metformin, a putative anti-inflammatory agent, also upregulates ACE2 expression in Calu-3 and endothelial cells. We hypothesized that IL-10 could be a danger signal, and its elevation could possibly represent a feedback mechanism fighting inflammation. Although further confirmatory studies are required, inducing IL-10 upregulation could be clinically relevant in COVID-19-associated acute respiratory distress syndrome (ARDS) and vasculitis, by reinforcing ACE2 levels.

Lock, Stock and Barrel: Role of Renin-Angiotensin-Aldosterone System in Coronavirus Disease 2019

Since the end of 2019, the medical-scientific community has been facing a terrible pandemic caused by a new airborne viral agent known as SARS-CoV2. Already in the early stages of the pandemic, following the discovery that the virus uses the ACE2 cell receptor as a molecular target to infect the cells of our body, it was hypothesized that the renin-angiotensin-aldosterone system was involved in the pathogenesis of the disease. Since then, numerous studies have been published on the subject, but the exact role of the renin-angiotensin-aldosterone system in the pathogenesis of COVID-19 is still a matter of debate. RAAS represents an important protagonist in the pathogenesis of COVID-19, providing the virus with the receptor of entry into host cells and determining its organotropism. Furthermore, following infection, the virus is able to cause an increase in plasma ACE2 activity, compromising the normal function of the RAAS. This dysfunction could contribute to the establishment of the thrombo-inflammatory state characteristic of severe forms of COVID-19. Drugs targeting RAAS represent promising therapeutic options for COVID-19 sufferers.

Receptor Interactions of Angiotensin II and Angiotensin Receptor Blockers-Relevance to COVID-19

Angiotensin II (Ang II) may contain a charge relay system (CRS) involving Tyr/His/carboxylate, which creates a tyrosinate anion for receptor activation. Energy calculations were carried out to determine the preferred geometry for the CRS in the presence and absence of the Arg guanidino group occupying position 2 of Ang II. These findings suggest that Tyr is preferred over His for bearing the negative charge and that the CRS is stabilized by the guanidino group. Recent crystallography studies provided details of the binding of nonpeptide angiotensin receptor blockers (ARBs) to the Ang II type 1 (AT1) receptor, and these insights were applied to Ang II. A model of binding and receptor activation that explains the surmountable and insurmountable effects of Ang II analogues sarmesin and sarilesin, respectively, was developed and enabled the discovery of a new generation of ARBs called bisartans. Finally, we determined the ability of the bisartan BV6(TFA) to act as a potential ARB, demonstrating similar effects to candesartan, by reducing vasoconstriction of rabbit iliac arteries in response to cumulative doses of Ang II. Recent clinical studies have shown that Ang II receptor blockers have protective effects in hypertensive patients infected with SARS-CoV-2. Therefore, the usage of ARBS to block the AT1 receptor preventing the binding of toxic angiotensin implicated in the storm of cytokines in SARS-CoV-2 is a target treatment and opens new avenues for disease therapy.

The Impact of Telmisartan on Cardiometabolic Risk Factors in Hypertensive Male Siblings of Women With Polycystic Ovary Syndrome

Brothers of women with polycystic ovary syndrome (PCOS) were found to be at increased risk for cardiometabolic disorders. This risk may be exacerbated by concurrent poorly controlled hypertension. Angiotensin II receptor blockers are the most frequently used antihypertensive drugs. The aim of the present study was to compare blood pressure-lowering and pleiotropic effects of telmisartan between male siblings of PCOS probands and unrelated men. The study included 2 age-, blood pressure-, and mass index-matched groups of men with grade 1 hypertension: 24 brothers of women with PCOS (group A) and 26 brothers of healthy women (group B). All subjects were treated with telmisartan (80 mg daily). Blood pressure, glucose homeostasis markers, and plasma lipids, as well as plasma levels of total testosterone, bioavailable testosterone, androstenedione, uric acid, high-sensitivity C-reactive protein (hsCRP), homocysteine, fibrinogen, and 25-hydroxyvitamin D were measured before and after 12 weeks of therapy. At entry, there were between-group differences in the degree of insulin resistance, plasma levels of high-density lipoprotein-cholesterol, triglycerides, calculated bioavailable testosterone, androstenedione, hsCRP, and 25-hydroxyvitamin D. Although telmisartan reduced blood pressure in both study groups, this effect was stronger in group B. Irrespective of the study group, the drug improved insulin sensitivity and reduced circulating levels of uric acid and homocysteine, but these effects were more pronounced in group B than group A. Only in group B, telmisartan decreased hsCRP and fibrinogen, as well as increased 25-hydroxyvitamin D. The obtained results suggest that hypertensive male relatives of PCOS probands may gain less benefit from telmisartan treatment than unrelated hypertensive men.

Rational Design and Synthesis of AT1R Antagonists

Hypertension is one of the most common diseases nowadays and is still the major cause of premature death despite of the continuous discovery of novel therapeutics. The discovery of the Renin Angiotensin System (RAS) unveiled a path to develop efficient drugs to fruitfully combat hypertension. Several compounds that prevent the Angiotensin II hormone from binding and activating the AT1R, named sartans, have been developed. Herein, we report a comprehensive review of the synthetic paths followed for the development of different sartans since the discovery of the first sartan, Losartan.

Presence of nitrosamine impurities in medicinal products

In 2018, some sartan medicinal products were reported to be contaminated with nitrosamine compounds, which are potent mutagenic carcinogens. Two nitrosamines received particular attention: N -nitrosodimethylamine (NDMA) and N-nitrosodiethylamine (NDEA). These have since been confirmed in different types of medicinal products, including ranitidine and metformin. Consequently, the European Medicines Agency (EMA) started an investigation into the cause of contamination and an assessment of the risk to patients taking contaminated medicinal products. The main source of contamination were changes in production, which involves combinations of amines and nitrogen compounds and the use of specific catalysts and reagents. Withdrawals of medicinal products that took place in Croatia did not lead to a shortage of sartan- or metformin-containing medicines. Moreover, ranitidine had been preventively withdrawn all over the EU, including Croatia, creating shortages at the time, but was subsequently replaced with therapeutic alternatives.

Calcitonin gene‑related peptide‑mediated pharmacological effects in cardiovascular and gastrointestinal diseases (Review)

Calcitonin gene‑related peptide (CGRP) is the predominant neurotransmitter located in sensory nerves. This peptide is extensively distributed in central and peripheral tissues. CGRP causes relaxation of cardiovascular smooth muscle cells and confers protection against ischaemic myocardium and cardiac remodeling. The pharmacological effects of nitroglycerine and rutaecarpine have been demonstrated to be associated with an increase in the synthesis and release of CGRP. In the gastrointestinal tissues, CGRP participates in the regulation of gastrointestinal function, and exerts protective effects on gastric mucosa. Rutaecarpine, capsaicin and its derivatives, such as evodiamine, decrease gastric mucosal damage induced by several factors, including increased synthesis and release of CGRP. Taken together, this review focuses on the pharmacological effects of several CGRP related canonical drugs and suggests that synthesis and secretion of CGRP exhibit significant therapeutic effects in the occurrence and development of cardiovascular and gastrointestinal diseases.

Clinical and pharmacological characteristics of elderly patients admitted for bleeding: impact on in-hospital mortality

INTRODUCTION

Clinical and pharmacological characteristics of elderly patients hospitalized for bleeding and in-hospital mortality according to bleeding type are barely described.

METHODS

Retrospective cohort study of 13,496 consecutive patients admitted to internal medicine wards. Clinical characteristics, comorbidities and pharmacological treatments were collected for each patient. Predictors of in-hospital mortality were investigated.

RESULTS

Overall, 531 (3.9%) patients were admitted for bleeding: 189 clinically relevant non-major bleeding, 106 cerebral and 236 major non-cerebral (95.8% gastrointestinal (GI)). Among 106 cerebral bleedings, 28.3% and 24.5% were typical and atypical intracranial, respectively, and 47.2% were subdural haemorrhages. Most of patients with GI bleeding presented with anaemia (90.7%). A similar rate of GI bleeding was found in aspirin-treated patients taking or not proton pump inhibitors (PPI). In-hospital mortality was 9.98%. Age ≥80 years (odds ratio (OR) 2.513, p=.005), cerebral bleeding (OR 5.373, p<.001), eGFR <30 ml/min/m² (OR 2.388, p=.035) and COPD (OR 2.362, p=.024) were positively associated with mortality, while ACE inhibitors/ARBs use was negatively associated (OR 0.383, p=.028).

CONCLUSIONS

The most frequent type of major haemorrhage was GI bleeding, which was not modified by the use of PPI in patients taking aspirin. Cerebral bleeding increased all-cause death, which was lower in ACE inhibitors/ARBs users. KEY MESSAGE Gastrointestinal (GI) bleeding was the most common reason for hospital admission. The rate of GI bleeding was similar in patients on aspirin using or not PPI. Cerebral bleeding increased in-hospital mortality, which was lower in patients taking ACE inhibitors/ARBs.

Angiotensin Receptor 1 Blockers Prolong Time to Recurrence after Radiofrequency Ablation in Hepatocellular Carcinoma patients: A Retrospective Study

Inhibition of angiotensin II synthesis seems to decrease hepatocellular carcinoma recurrence after radical therapies; however, data on the adjuvant role of angiotensin II receptor 1 blockers (sartans) are still lacking. Aim of the study was to evaluate whether sartans delay time to recurrence and prolong overall survival in hepatocellular carcinoma patients after radiofrequency ablation. Data on 215 patients were reviewed. The study population was classified into three groups: 113 (52.5%) patients who received neither angiotensin-converting enzyme inhibitors nor sartans (group 1), 59 (27.4%) patients treated with angiotensin-converting enzyme inhibitors (group 2) and 43 (20.1%) patients treated with sartans (group 3). Survival outcomes were analyzed using Kaplan-Meier analysis and compared with log-rank test. In the whole study population, 85.6% of patients were in Child-Pugh A-class and 89.6% in Barcelona Clinic Liver Cancer A stage. Median maximum tumor diameter was 30 mm (10-40 mm) and alpha-fetoprotein was 25 (1.1-2100) IU/mL. No differences in baseline characteristics among the three groups were reported. Median overall survival was 48 months (42-51) in group 1, 51 months (42-88) in group 2, and 63 months (51-84) in group 3 (p = 0.15). Child-Pugh stage and Model for End-staging Liver Disease (MELD) score resulted as significant predictors of overall survival in multivariate analysis. Median time to recurrence was 33 months (24-35) in group 1, 41 (23-72) in group 2 and 51 months (42-88) in group 3 (p = 0.001). Number of nodules and anti-angiotensin treatment were confirmed as significant predictors of time to recurrence in multivariate analysis. Sartans significantly improved time to recurrence after radiofrequency ablation in hepatocellular carcinoma patients but did not improve overall survival.

[Features of fibrosis and disorders of the collagen metabolism of the interstitial matrix of the myocardium in patients with arterial hypertension and possibilities of their correction with sartname.]

Metabolic disorders of the interstitial heart and vessels matrix in hypertension develop due to chronic stretching of their walls. For estimation the involutive and hypertensive changes in interstitial matrix of the heart and vessels we have been examined 30 normotensive elderly women and 30 patients of same age with arterial hypertension (AH) II stage, as well as the possibility of their correction by valsartan and veroshpiron. The next parameters of investigation used: the volume fraction of interstitial collagen (VFIC) in myocardium, cardiovascular conjugation (CVC), serum concentrations of markers of systemic collagenogenesis - COL-1, TGF-β1, MMP-1, TIMP-1, Gal-3. CVC reflected the hard-elastic properties of the myocardium and arterial vessels, which was elevated in women with AH. A high intensity of LV myocardial fibrosis was revealed with a significant increase in the VFIC content in elderly patients with AH compared with normotensive patients. This is due to the increased activity of fibrosis markers. There was a decrease in their level after antihypertensive therapy, which proved its antifibrotic effect.

Plantar Psoriasis Associated with Olmesartan

BACKGROUND

Psoriasis is a chronic inflammatory skin disorder that may be initiated or exacerbated by some drug intakes. Some of the most common medications known to trigger or worsen existing psoriasis include lithium, gold salts, beta blockers and antimalarials.

CONCLUSION

We report an exceptional case of plantar psoriasis in a woman who was treated by olmesartan for 3 years.

What is the role of angiotensin receptor blockers in treatment of hyperuricemia coexisting with arterial hypertension?

Angiotensin receptor blockers or sartans are used to treat arterial hypertension. Hyperuricemia and arterial hypertension often coexist in patients with metabolic syndrome. Also hyperuricemia is correlated with an increased risk of cardiovascular disease and death. There are data suggesting that lowering serum urate may assist in control of arterial hypertension and use of certain drugs for arterial hypertension may reduce the serum uric acid level. The Polish Society of Arterial Hypertension recommends losartan for treatment of arterial hypertension in patients with coexisting hyperuricemia. The aim of the present review was to find evidence supporting the concept of use and explain the role of sartans in treatment of hyperuricemia. Thirty-five original and review articles about hyperuricemia and arterial hypertension focusing on the use of sartans in both these medical conditions were analyzed. In conclusion, sartans should be recommended for treatment of hyperuricemia coexisting with arterial hypertension in patients without bilateral renal artery stenosis and with exclusion of pregnant women.

Fragmentation studies of sartans by electrospray ionization mass spectrometry

Sartans and related analogues with 5-oxo-l, 2, 4-oxadiazole ring and tetrazole ring are investigated in detail using collision-induced dissociation (CID) method in positive ion mode by electrospray ionization tandem mass spectrometry (ESI-MSⁿ ). It is found that the protonated sartans and related analogues tend to form the N-substituted-3-substituted phenanthridin-6-amine ion which has a large conjugative structure. The possible fragmentation pathways were proposed for the first time, and the key structure of product ions was confirmed by high resolution tandem mass spectrometry and theoretical calculation. It is very helpful for understanding the intriguing roles of sartans analogues in fragmentation reactions and enriching the knowledge of the gas-phase chemistry of the oxadiazole and tetrazole ring. Copyright © 2017 John Wiley & Sons, Ltd.

Synthesis and Physicochemical Characterization of the Process-Related Impurities of Olmesartan Medoxomil. Do 5-(Biphenyl-2-yl)-1-triphenylmethyltetrazole Intermediates in Sartan Syntheses Exist?

During the process development for multigram-scale synthesis of olmesartan medoxomil (OM), two principal regioisomeric process-related impurities were observed along with the final active pharmaceutical ingredient (API). The impurities were identified as N-1- and N-2-(5-methyl-2-oxo-1,3-dioxolen-4-yl)methyl derivatives of OM. Both compounds, of which N-2 isomer of olmesartan dimedoxomil is a novel impurity of OM, were synthesized and fully characterized by differential scanning calorimetry (DSC), infrared spectroscopy (IR), nuclear magnetic resonance spectroscopy (NMR) and high-resolution mass spectrometry/electrospray ionization (HRMS/ESI). Their ¹H, (13)C and (15)N nuclear magnetic resonance signals were fully assigned. The molecular structures of N-triphenylmethylolmesartan ethyl (N-tritylolmesartan ethyl) and N-tritylolmesartan medoxomil, the key intermediates in OM synthesis, were solved and refined using single-crystal X-ray diffraction (SCXRD). The SCXRD study revealed that N-tritylated intermediates of OM exist exclusively as one of the two possible regioisomers. In molecular structures of these regioisomers, the trityl substituent is attached to the N-2 nitrogen atom of the tetrazole ring, and not to the N-1 nitrogen, as has been widely reported up to the present. This finding indicates that the reported structural formula of N-tritylolmesartan ethyl and N-tritylolmesartan medoxomil, as well as their systematic chemical names, must be revised. The careful analysis of literature spectroscopic data for other sartan intermediates and their analogs with 5-(biphenyl-2-yl)tetrazole moiety showed that they also exist exclusively as N-2-trityl regioisomers.

Angiotensin receptor blockers improve survival outcomes after radiofrequency ablation in hepatocarcinoma patients

BACKGROUND AND AIM

Inhibition of angiotensin II synthesis seems to decrease hepatocellular carcinoma recurrence after radical therapies; however, data on the adjuvant role of angiotensin II receptor 1 blockers (sartans) are still lacking. The aim of the study was to evaluate whether sartans delay time to recurrence and prolong overall survival in hepatocellular carcinoma patients after radiofrequency ablation.

METHODS

Data on 153 patients were reviewed. The study population was classified into three groups: 73 (47.8%) patients who received neither angiotensin-converting enzyme inhibitors nor sartans (group 1), 49 (32%) patients treated with angiotensin-converting enzyme inhibitors (group 2), and 31 (20.2%) patients treated with sartans (group 3). Survival outcomes were analysed by means of Kaplan-Meier analysis and compared with log-rank test.

RESULTS

In the whole study population, 85.6% of patients were in Child-Pugh A class and 89.6% in Barcelona Clinic Liver Cancer A stage. Median maximum tumor diameter was 30 mm (10-40) and alpha fetoprotein was 25 (1.1-2100) UI/mL. No differences in baseline characteristics among the three groups were reported. Median overall survival was 48 months (95% confidence interval: 31-58) in group 1, 72 months (49-89) in group 2, and 84 months (58-92) in group 3 (P = 0.02). Median time to recurrence was 26 (15-42), 44 (33-72), and 69 (44-74) months in the three groups, respectively (P = 0.02). Sartan therapy was a significant predictor of longer overall survival and delayed time to recurrence on multivariate analysis.

CONCLUSION

Sartans significantly improved overall survival and time to recurrence after radiofrequency ablation in hepatocellular carcinoma patients.

Neuroprotective effects of angiotensin receptor blockers

Angiotensin II receptor blockers (ARBs, collectively called sartans) are widely used compounds therapeutically effective in cardiovascular disorders, renal disease, the metabolic syndrome, and diabetes. It has been more recently recognized that ARBs are neuroprotective and have potential therapeutic use in many brain disorders. ARBs ameliorate inflammatory and apoptotic responses to glutamate, interleukin 1β and bacterial endotoxin in cultured neurons, astrocytes, microglial, and endothelial cerebrovascular cells. When administered systemically, ARBs enter the brain, protecting cerebral blood flow, maintaining blood brain barrier function and decreasing cerebral hemorrhage, excessive brain inflammation and neuronal injury in animal models of stroke, traumatic brain injury, Alzheimer's and Parkinson's disease and other brain conditions. Epidemiological analyses reported that ARBs reduced the progression of Alzheimer's disease, and clinical studies suggested amelioration of cognitive loss following stroke and aging. ARBs are pharmacologically heterogeneous; their effects are not only the result of Ang II type 1(AT1) receptor blockade but also of additional mechanisms selective for only some compounds of the class. These include peroxisome proliferator-activated receptor gamma activation and other still poorly defined mechanisms. However, the complete pharmacological spectrum and therapeutic efficacy of individual ARBs have never been systematically compared, and the neuroprotective efficacy of these compounds has not been rigorously determined in controlled clinical studies. The accumulation of pre-clinical evidence should promote further epidemiological and controlled clinical studies. Repurposing ARBs for the treatment of brain disorders, currently without effective therapy, may be of immediate and major translational value.

Neuroprotective effects of angiotensin receptor blockers

Angiotensin II receptor blockers (ARBs, collectively called sartans) are widely used compounds therapeutically effective in cardiovascular disorders, renal disease, the metabolic syndrome, and diabetes. It has been more recently recognized that ARBs are neuroprotective and have potential therapeutic use in many brain disorders. ARBs ameliorate inflammatory and apoptotic responses to glutamate, interleukin 1β and bacterial endotoxin in cultured neurons, astrocytes, microglial, and endothelial cerebrovascular cells. When administered systemically, ARBs enter the brain, protecting cerebral blood flow, maintaining blood brain barrier function and decreasing cerebral hemorrhage, excessive brain inflammation and neuronal injury in animal models of stroke, traumatic brain injury, Alzheimer's and Parkinson's disease and other brain conditions. Epidemiological analyses reported that ARBs reduced the progression of Alzheimer's disease, and clinical studies suggested amelioration of cognitive loss following stroke and aging. ARBs are pharmacologically heterogeneous; their effects are not only the result of Ang II type 1(AT1) receptor blockade but also of additional mechanisms selective for only some compounds of the class. These include peroxisome proliferator-activated receptor gamma activation and other still poorly defined mechanisms. However, the complete pharmacological spectrum and therapeutic efficacy of individual ARBs have never been systematically compared, and the neuroprotective efficacy of these compounds has not been rigorously determined in controlled clinical studies. The accumulation of pre-clinical evidence should promote further epidemiological and controlled clinical studies. Repurposing ARBs for the treatment of brain disorders, currently without effective therapy, may be of immediate and major translational value.

Angiotensin II type 1 receptor blockers increase tolerance of cells to copper and cisplatin

The human pathology Wilson disease (WD) is characterized by toxic copper (Cu) accumulation in brain and liver, resulting in, among other indications, mitochondrial dysfunction and apoptosis of hepatocytes. In an effort to identify novel compounds that can alleviate Cu-induced toxicity, we screened the Pharmakon 1600 repositioning library using a Cu-toxicity yeast screen. We identified 2 members of the drug class of Angiotensin II Type 1 receptor blockers (ARBs) that could increase yeast tolerance to Cu, namely Candesartan and Losartan. Subsequently, we show that specific ARBs can increase yeast tolerance to Cu and/or the chemotherapeutic agent cisplatin (Cp). The latter also induces mitochondrial dysfunction and apoptosis in mammalian cells. We further demonstrate that specific ARBs can prevent the prevalence of Cu-induced apoptotic markers in yeast, with Candesartan Cilexetil being the ARB which demonstrated most pronounced reduction of apoptosis-related markers. Next, we tested the sensitivity of a selection of yeast knockout mutants affected in detoxification of reactive oxygen species (ROS) and Cu for Candesartan Cilexetil rescue in presence of Cu. These data indicate that Candesartan Cilexetil increases yeast tolerance to Cu irrespectively of major ROS-detoxifying proteins. Finally, we show that specific ARBs can increase mammalian cell tolerance to Cu, as well as decrease the prevalence of Cu-induced apoptotic markers. All the above point to the potential of ARBs in preventing Cu-induced toxicity in yeast and mammalian cells.

Analysis of Sartans: a review

The risk of cardiovascular diseases is closely related to hypertension, high cholesterol levels, and diabetes. When these risk factors appear together they are referred to as a metabolic syndrome. In the treatment of cardiovascular diseases, a combination of antihypertensive, hypolipemiant, and antidiabetic drugs is often applied. Diuretics (chlortalidone, hydrochlorothiazide, etc.) and angiotensin II receptors antagonist (sartans) are used to control hypertension, whereas statins (fluvastatin, simvastatin, etc.) are used to reduce cholesterol levels. This review is concerned with methods for the analysis of sartans in various matrices, such as pharmaceutical formulations, environmental and biological samples, and discusses the current status of stability studies of sartans . It also presents analytical methods for the simultaneous determination of sartans, diuretics, and statins.