Candesartan Cilexetil Attenuates Arrhythmogenicity Following Pressure Overload in Rats via the Modulation of Cardiac Electrical and Structural Remodeling and Calcium Handling Dysfunction

Background

Cardiac hypertrophy is associated with abnormal electrophysiology and increased arrhythmia risk. This study assessed whether candesartan cilexetil, an angiotensin II type 1 receptor blocker, could suppress arrhythmogenecity by attenuating cardiac electrical remodeling and calcium mishandling in rats with pressure‐overload hypertrophy.

Methods and Results

Male Sprague‐Dawley rats were randomly subjected to abdominal aorta banding or sham procedure and received either candesartan cilexetil (3.0 mg/kg per day) or vehicle by gavage for 5 weeks. Pressure overload was characterized by compensated left ventricular (LV) hypertrophy and fibrosis, increased LV pressure and its decay time, and prolonged corrected QT interval, all of which were attenuated by candesartan cilexetil treatment. Candesartan cilexetil–treated banded rat hearts displayed shorter QT intervals and lower vulnerability to atrial and ventricular tachyarrhythmias than vehicle‐treated banded hearts. Candesartan cilexetil prevented banding‐induced prolonged action potential duration and reduced the occurrence of triggered activity in LV papillary muscles. In addition, the prolonged time to 50% cell relengthening and calcium transient decay time were normalized in LV myocytes from candesartan cilexetil–treated banded rats, along with a normalization of decreased SERCA2a (sarco[endo]plasmic reticulum calcium‐ATPase) expression in LV tissues. Furthermore, candesartan cilexetil normalized depressed transient outward potassium current densities and protein and mRNA levels of both voltage‐gated potassium 4.2 and 4.3 channel subunits (Kv4.2 and Kv4.3) in banded rats.

Conclusions

Candesartan cilexetil protects the heart from pressure overload‐induced adverse electrical remodeling by preserving potassium channel densities. In addition, calcium handling and its molecular regulation also improved after treatment. These beneficial effects may contribute to a lower susceptibility to arrhythmias in hearts from candesartan cilexetil–treated pressure‐overloaded rats.

Repurposing Candesartan Cilexetil as Antibacterial Agent for MRSA Infection

Staphylococcus aureus is an important pathogen causing hospital-acquired infections. Methicillin-resistant S. aureus (MRSA), biofilms, and persisters are highly tolerant to traditional antibiotics and make it difficult to treat. Therefore, new antimicrobial agents are urgently needed to treat hard-to-eradicate diseases caused by this bacterium. In this study, candesartan cilexetil (CC), an angiotensin hypertension drug, had strong antimicrobial activity against S. aureus with minimal inhibitory concentrations (MICs) and minimal bactericidal concentrations (MBCs) of 8-16 μg/ml and 16-32 μg/ml. CC exhibited limited cytotoxicity and low potential to induce drug resistance. In addition, it showed a synergistic antibacterial effect when combined with gentamicin and tobramycin. The effective concentrations to inhibit MRSA biofilm formation were 16-64 μg/ml, and intractable persisters were killed at 4-8 × MIC. Through the analysis of its mechanism of action, it was evident that the membrane permeability was disrupted as well as the cell structure was damaged. Furthermore, we demonstrated that CC had antibacterial effects in vivo in MRSA-infected murine skin abscess models. In conclusion, these results imply that CC might be a potential antibacterial agent for the treatment of S. aureus-associated infections.

Formulation and Bioavailability of Novel Mucoadhesive Buccal Films for Candesartan Cilexetil in Rats

Candesartan cilexetil (CC) is an antihypertensive drug. It has low solubility and faces hepatic first-pass metabolism after oral ingestion. We formulated bioadhesive buccal films and studied the respective drug pharmacokinetics. Different bioadhesive films were prepared (40, 80, 120, 160, 200, and 240 mg CC per film) by using the solvent casting method. The drug concentrations used affect the drug entrapment mechanism, which was reflected in the film physicochemical properties like thickness, weight, drug content, bioadhesion, and drug release. Low drug concentration (F2, 40 mg per film) led to minute drug crystal dispersion while increasing the drug concentration (F7, 240 mg per film) showed drug crystal encapsulation, which affects the drug release. The drug pharmacokinetic from the prepared films was studied compared to the oral form by serial blood sampling via an inserted catheter in the carotid of rats. High-Performance Liquid Chromatography assay was used to measure the plasma concentration of CC in different forms. Compared to other films, the F2 showed the highest maximal concentration (Cmax) and the lowest elimination half-life (t_1/2). Bioadhesion buccal film of CC has better bioavailability, especially at low concentrations. The ease, robustness, and ruggedness of the preparation suggests the same procedure for drugs like CC.

New Peceol™/Span™ 60 Niosomes Coated with Chitosan for Candesartan Cilexetil: Perspective Increase in Absolute Bioavailability in Rats

PURPOSE

Candesartan cilexetil (CC), a prodrug of candesartan (CDT), is a class II BCS drug that suffers from poor oral bioavailability because of low aqueous solubility, P-gp efflux and first-pass metabolism. The absolute bioavailability reported for CC was only 15% and the methods to increase it remain elusive, thus the aim of our work was to prepare new CC-loaded niosomes encompassing, for the first time, glycerol monooleate GMO (Peceol™), as P-gp efflux inhibitor and promoter of lymphatic transport with Span™ 60 as bioenhancer. The prepared niosomes were further coated with chitosan for augmenting the CC oral absorption.

METHODS

The niosomes were prepared by thin film hydration method through quality by design approach, using two levels of each of three critical process parameters (CPPs), namely, XA (the molar ratio of surfactant mixture to cholesterol) at a ratio of 1:1 or 2:1; XB (the molar ratio of Span™ 60 to Peceol™) at a ratio of 1:1 or 2:1; and XC (the drug amount) at 15 mg or 30 mg. The investigated critical quality attributes (CQAs) were entrapment efficiency percent, particle size, and polydispersity index. The optimized uncoated and chitosan coated formulations were subjected to DSC and stability study. In vitro drug release, biocompatibility with Caco-2 cells and lastly the absolute bioavailability evaluation in rats were assessed.

RESULTS

The physical properties of the optimized and stable niosomes were satisfactory. The ingredients were compatible with each other and biocompatible with Caco-2 cells. The synergistic combination of Peceol™ and Span™ 60 probably surmounted the P-gp efflux with an increase in oral absolute bioavailability of niosomes to five times that of CC suspension.

CONCLUSION

The new niosomal formulations of CC containing Peceol™ with Span™ 60 and cholesterol either uncoated or coated with chitosan were a successful paradigm in achieving high oral absolute bioavailability and increased Caco-2 cells biocompatibility.

17-a-estradiol late in life extends lifespan in aging UM-HET3 male mice; nicotinamide riboside and three other drugs do not affect lifespan in either sex

In genetically heterogeneous mice produced by the CByB6F1 x C3D2F1 cross, the "non-feminizing" estrogen, 17-α-estradiol (17aE2), extended median male lifespan by 19% (p < 0.0001, log-rank test) and 11% (p = 0.007) when fed at 14.4 ppm starting at 16 and 20 months, respectively. 90th percentile lifespans were extended 7% (p = 0.004, Wang-Allison test) and 5% (p = 0.17). Body weights were reduced about 20% after starting the 17aE2 diets. Four other interventions were tested in males and females: nicotinamide riboside, candesartan cilexetil, geranylgeranylacetone, and MIF098. Despite some data suggesting that nicotinamide riboside would be effective, neither it nor the other three increased lifespans significantly at the doses tested. The 17aE2 results confirm and extend our original reports, with very similar results when started at 16 months compared with mice started at 10 months of age in a prior study. The consistently large lifespan benefit in males, even when treatment is started late in life, may provide information on sex-specific aspects of aging.

Candesartan Cilexetil In Vitro-In Vivo Correlation: Predictive Dissolution as a Development Tool

The main objective of this investigation was to develop an in vitro-in vivo correlation (IVIVC) for immediate release candesartan cilexetil formulations by designing an in vitro dissolution test to be used as development tool. The IVIVC could be used to reduce failures in future bioequivalence studies. Data from two bioequivalence studies were scaled and combined to obtain the dataset for the IVIVC. Two-step and one-step approaches were used to develop the IVIVC. Experimental solubility and permeability data confirmed candesartan cilexetil. Biopharmaceutic Classification System (BCS) class II candesartan average plasma profiles were deconvoluted by the Loo-Riegelman method to obtain the oral fractions absorbed. Fractions dissolved were obtained in several conditions in USP II and IV apparatus and the results were compared calculating the f2 similarity factor. Levy plot was constructed to estimate the time scaling factor and to make both processes, dissolution and absorption, superimposable. The in vitro dissolution experiment that reflected more accurately the in vivo behavior of the products of candesartan cilexetil employed the USP IV apparatus and a three-step pH buffer change, from 1.2 to 4.5 and 6.8, with 0.2% of Tween 20. This new model was able to predict the in vivo differences in dissolution and it could be used as a risk-analysis tool for formulation selection in future bioequivalence trials.

Solid State Stability and Kinetics of Degradation for Candesartan-Pure Compound and Pharmaceutical Formulation

The aim of this work was to assess the impact of an excipient in a pharmaceutical formulation containing candesartan cilexetil over the decomposition of the active pharmaceutical ingredient and to comparatively investigate the kinetics of degradation during thermolysis in an oxidative atmosphere under controlled thermal stress. To achieve this, the samples were chosen as follows: pure candesartan cilexetil and a commercial tablet of 32 mg strength. As a first investigational tool, Universal attenuated total reflection Fourier transform infrared (UATR-FTIR) spectroscopy was chosen in order to confirm the purity and identity of the samples, as well as to check if any interactions took place in the tablet between candesartan cilexetil and excipients under ambient conditions. Later on, samples were investigated by thermal analysis, and the elucidation of the decomposition mechanism was achieved solely after performing an in-depth kinetic study, namely the use of the modified non-parametric kinetics (NPK) method, since other kinetic methods (American Society for Testing and Materials—ASTM E698, Friedman and Flynn–Wall–Ozawa) led to inadvertencies. The NPK method suggested that candesartan cilexetil and the tablet were degraded by the contribution of two steps, the main being represented by chemical degradation and the secondary being a physical transformation. The excipients chosen in the formulation seemed to have a stabilizing effect on the decomposition of the candesartan cilexetil that was incorporated into the tablet, relative to pure active pharmaceutical ingredient (API), since the apparent activation energy for the decomposition of the tablet was 192.5 kJ/mol, in comparison to 154.5 kJ/mol for the pure API.

Preparation, characterization and ex vivo-in vivo assessment of candesartan cilexetil nanocrystals via solid dispersion technique using an alkaline esterase activator carrier

The objective of this study was to improve candesartan cilexetil (CC) efficacy by formulating nanocrystals via solid dispersion (SD) technique using tromethamine (Tris). SD was prepared by solvent evaporation at different drug carrier ratios, evaluated for particle size, vitro dissolution studies, TEM, FTIR, and X-ray powder diffraction. Ex vivo, in vivo pharmacokinetic parameters were conducted on selected formulae compared to drug suspension and marketed product. Size analysis demonstrated formation of particles in the nanorange lower than 300 nm. A burst drug release followed by an improved dissolution was observed indicating instant formation of nanocrystals along with amorphization as confirmed by X-ray diffraction. FTIR studies suggested the absence of chemical interaction between Tris and CC. TEM revealed formation of irregular oval nanoparticles. SD-1:5 has higher apparent permeability coefficient compared to CC suspension. Furthermore, the pharmacokinetic results proved the ability of the formed nanoparticles to enhance the efficacy of CC compared to drug suspension and marketed product. In conclusion, using of Tris as alkaline esterase activator carrier could be a promising tool to bypass the controversial effect of esterase enzymes that may be a source for inter-individual variations affecting ester prodrug candidates' efficacy.

Efficacy and Safety of Imarikiren in Patients with Type 2 Diabetes and Microalbuminuria: A Randomized, Controlled Trial

BACKGROUND AND OBJECTIVES

Imarikiren is a novel, potent, and selective direct renin inhibitor that has shown high oral availability during clinical development for the treatment of diabetic nephropathy. We evaluated the efficacy and safety of imarikiren in patients with type 2 diabetes mellitus and microalbuminuria.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This was a randomized, multicenter, placebo-controlled, double-blind, phase 2, dose-finding trial. A total of 415 patients were randomized to imarikiren 5, 20, 40, or 80 mg; placebo; or candesartan cilexetil 8 mg treatment for 12 weeks. The primary end point was change in log-transformed urine albumin-to-creatinine ratio from baseline to the end of treatment analyzed using analysis of covariance and a fixed sequence testing procedure. Secondary efficacy end points included urine albumin-to-creatinine ratio at each assessment point and remission and progression rates. Exploratory efficacy end points included eGFR and sitting BP before dosing.

RESULTS

Changes in the urine albumin-to-creatinine ratio from baseline to the end of treatment were 16% (placebo), -16% (imarikiren 5 mg), -27% (imarikiren 20 mg), -38% (imarikiren 40 mg), -39% (imarikiren 80 mg), and -31% (candesartan cilexetil 8 mg). Urine albumin-to-creatinine ratio reductions from baseline were statistically significant in all imarikiren groups versus placebo (P<0.001 each) as well as for candesartan cilexetil 8 mg versus placebo (P<0.001). Remission rates (urine albumin-to-creatinine ratio <30 mg/g creatinine and decreased ≥30% from baseline) were higher in all imarikiren groups versus the placebo group. Incidence of adverse events was higher in the imarikiren 80-mg group (52%) versus placebo (42%) and candesartan cilexetil (43%) groups. Incidence of adverse events for the other imarikiren groups ranged from 33% to 42%. Adverse events were mild or moderate in severity. All imarikiren doses were well tolerated.

CONCLUSIONS

Imarikiren resulted in a dose-dependent improvement in albuminuria compared with placebo, and it was well tolerated in patients with type 2 diabetes mellitus and microalbuminuria.

Host-Guest Interactions between Candesartan and Its Prodrug Candesartan Cilexetil in Complex with 2-Hydroxypropyl-β-cyclodextrin: On the Biological Potency for Angiotensin II Antagonism

Renin-angiotensin aldosterone system inhibitors are for a long time extensively used for the treatment of cardiovascular and renal diseases. AT1 receptor blockers (ARBs or sartans) act as antihypertensive drugs by blocking the octapeptide hormone Angiotensin II to stimulate AT1 receptors. The antihypertensive drug candesartan (CAN) is the active metabolite of candesartan cilexetil (Atacand, CC). Complexes of candesartan and candesartan cilexetil with 2-hydroxylpropyl-β-cyclodextrin (2-HP-β-CD) were characterized using high-resolution electrospray ionization mass spectrometry and solid state ¹³C cross-polarization/magic angle spinning nuclear magnetic resonance (CP/MAS NMR) spectroscopy. The ¹³C CP/MAS results showed broad peaks especially in the aromatic region, thus confirming the strong interactions between cyclodextrin and drugs. This experimental evidence was in accordance with molecular dynamics simulations and quantum mechanical calculations. The synthesized and characterized complexes were evaluated biologically in vitro. It was shown that as a result of CAN's complexation, CAN exerts higher antagonistic activity than CC. Therefore, a formulation of CC with 2-HP-β-CD is not indicated, while the formulation with CAN is promising and needs further investigation. This intriguing result is justified by the binding free energy calculations, which predicted efficient CC binding to 2-HP-β-CD, and thus, the molecule's availability for release and action on the target is diminished. In contrast, CAN binding was not favored, and this may allow easy release for the drug to exert its bioactivity.

Polymorphic and Quantum Chemistry Characterization of Candesartan Cilexetil: Importance for the Correct Drug Classification According to Biopharmaceutics Classification System

The recommended method for the biopharmaceutical evaluation of drug solubility is the shake flask; however, there are discrepancies reported about the solubility of certain compounds measured with this method, one of them is candesartan cilexetil. The present work aimed to elucidate the solubility of candesartan cilexetil by associating others assays such as stability determination, polymorphic characterization and in silico calculations of intrinsic solubility, ionized species, and electronic structures using quantum chemistry descriptors (frontier molecular orbitals and Fukui functions). For the complete biopharmaceutical classification, we also reviewed the permeability data available. The polymorphic form used was previously identified as the form I of candesartan cilexetil. The solubility was evaluated in biorelevant media in the pH range of 1.2-6.8 at 37.0°C according to the stability previously assessed. The solubility of candesartan cilexetil is pH dependent and the dose/solubility ratios obtained demonstrated the low solubility of the prodrug. The in silico calculations supported the found results and evidenced the main groups involved in the solvation, benzimidazole, and tetrazol-biphenyl. The human absolute bioavailability reported demonstrates that candesartan cilexetil has low permeability and when associated with the low solubility allows to classify it as class 4 of the Biopharmaceutics Classification System.

Formulation and Optimization of Candesartan Cilexetil Nano Lipid Carrier: In Vitro and In Vivo Evaluation

PURPOSE

The objective of this study was to formulate and optimize Candesartan Cilexetil (CC) loaded nanostructured lipid carriers (NLCs) for enhanced oral bioavailability.

METHOD

Glycerol monostearate (GMS), Oleic acid, Tween 80 and Span 40 were selected as a solid lipid, liquid lipid, surfactant and co- surfactant, respectively. The CC-NLCs were prepared by hot emulsion probe sonication technique and optimized using experimental design approach. The formulated CC-NLCs were evaluated for various physicochemical parameters and further optimized formulation (CC-NLC-Opt) was assessed for in vivo pharmacokinetic and pharmacodynamic activity.

RESULTS

The optimized formulation (CC-NLC-Opt) showed particle size (183.5±5.89nm), PDI (0.228±0.13), zeta potential (-28.2±0.99mV), and entrapment efficiency (88.9±3.69%). The comparative in vitro release study revealed that CC-NLC-Opt showed significantly better (p<0.05) release and enhanced permeation as compared to CC-suspension. The in vivo pharmacokinetic study gave many folds increase in oral bioavailability than CC suspension, which was further confirmed by antihypertensive activity in a murine model.

CONCLUSION

Thus, the results of ex vivo permeation, pharmacokinetic study and pharmacodynamics study suggest the potential of CC-NLCs for improved oral delivery.

Comparative Pharmaceutical Evaluation of Candesartan and Candesartan Cilexetil: Physicochemical Properties, In Vitro Dissolution and Ex Vivo In Vivo Studies

The aim of the present work is to answer the question is it possible to replace the ester prodrug candesartan cilexetil (CC) by its active metabolite candesartan (C) to bypass the in vivo variable effect of esterase enzymes. A comparative physicochemical evaluation was conducted through solubility, dissolution, and stability studies; additionally, ex vivo permeation and in vivo studies were assessed. C demonstrated higher solubility over CC at alkaline pH. Moreover, dissolution testing using the pharmacopeial method showed better release profile of C even in the absence of surfactant in the testing medium. Both drugs demonstrated a slight degradation in acidic pH after short-term stability. Instead, shifting to alkaline pH of 6.5 and 7.4 showed superiority of C solution stability compared to CC solution. The ex vivo permeation results demonstrated that the parent compound C has a significant (P < 0.05) enhanced permeation compared to its prodrug from CC, that agreed with in vivo results in which C suspension reached significantly (P < 0.05) higher C _max of 1.39 ± 0.59 μg/mL at T _max of 0.66 ± 0.11 h, while CC suspension reached C _max of 0.47 ± 0.22 μg/mL at T _max of 2.00 ± 0.27 h, a lag period of 40 min is needed prior to detection of any absorbed CC in plasma. Those findings are not in agreement with the previously reported rationale on the prodrug formation owing to the poor permeability of the parent compound, suggesting the possibility of marketing the parent drug candesartan for clinical use similarly to azilsartan and its prodrug.

Pharmacological evaluation of pioglitazone and candesartan cilexetil in a novel mouse model of non-alcoholic steatohepatitis, modified choline-deficient, amino acid-defined diet fed low-density lipoprotein receptor knockout mice

AIM

Low-density lipoprotein receptor knockout (LDLR-KO) mice fed a modified choline-deficient and amino acid-defined (mCDAA) diet show non-alcoholic steatohepatitis (NASH)-like pathophysiology. In order to pharmacologically benchmark this model, effects of pioglitazone (a thiazolidinedione) and candesartan cilexetil (an angiotensin II type 1 receptor blocker) on steatosis and liver fibrosis were examined.

METHODS

Pioglitazone (10 mg/kg) and candesartan cilexetil (3 mg/kg) were given orally once daily to LDLR-KO mice under mCDAA diet for 7 weeks. Blood biochemistry and hepatic histology were assessed, and hepatic gene expression levels and triglyceride content were measured.

RESULTS

Pioglitazone suppressed hepatic COL1A1 gene expression by 43% and attenuated hepatic fibrosis areas by 49%. Pioglitazone also decreased plasma alanine aminotransferase levels, liver weight, hepatic triglyceride content, and hepatic expression of other fibrosis-related genes such as TGFB1, SPP1, TIMP1, and IL6. Candesartan cilexetil suppressed hepatic COL1A1 gene expression by 33%, whereas the other end-points including hepatic fibrosis areas were not affected.

CONCLUSIONS

Pioglitazone showed anti-fibrotic effects accompanied by improving hepatic transaminase activity and hepatic lipid accumulation, but the effect of candesartan cilexetil was only limited, unlike previous reports for angiotensin II type 1 receptor blockers. As the pharmacological effects of pioglitazone in the current animal model are similar to those reported in patients with NASH, this model may represent some aspects of the pathophysiology of NASH. Further profiling using other agents or mechanisms that have been tested in the clinic will better clarify the utility of the animal model.

Fixed-dose combination of nifedipine gastrointestinal therapeutic system and candesartan cilexetil in patients with moderate-to-severe essential hypertension: an open-label, long-term safety and efficacy study

WHAT IS KNOWN AND OBJECTIVE

The nifedipine gastrointestinal therapeutic system (GITS)/candesartan cilexetil (N/C) combination was demonstrated to be an effective, well-tolerated antihypertensive therapy in a short-term study. The current study investigated the long-term safety and efficacy of a fixed-dose combination (FDC) of N/C therapy in moderate-to-severe essential hypertension.

METHODS

A multinational, 70-centre, open-label study of N/C treatment for 28 or 52 weeks at a target dose of N60 mg/C32 mg. The primary assessment included the incidence of treatment-emergent adverse events (TEAEs). Efficacy assessments included change from baseline in systolic and diastolic blood pressure (BP).

RESULTS AND DISCUSSION

A total of 508 patients were enrolled, with 417 (82·1%) completing week 28 of treatment. Of these, 200 patients continued treatment, as planned, to week 52, with 193 (96·5%) completing this period. At least one TEAE or drug-related TEAE were reported in 76·8% and 45·3% patients up to week 28, and in 80·7% and 46·9% up to week 52/end of study. Most TEAEs and drug-related TEAEs to week 52 (93·9% and 95·4%, respectively) were mild or moderate in intensity. Rates of drug-related serious AEs were low (0·6%). TEAE-related discontinuations occurred in 10% patients before week 28 and in no additional patients thereafter. N/C provided substantial, sustained reductions in mean systolic and diastolic BP from baseline: 30·1 ± 18·4 and 12·8 ± 10·7 mmHg, respectively, at week 52.

WHAT IS NEW AND CONCLUSIONS

Nifedipine GITS/candesartan cilexetil FDC at the target dose of 60 mg/32 mg was well tolerated for a study duration up to 52 weeks and provided sustained reductions in systolic and diastolic BP.

Nifedipine GITS/Candesartan Combination Therapy Lowers Blood Pressure Across Different Baseline Systolic and Diastolic Blood Pressure Categories: DISTINCT Study Subanalyses

DISTINCT was an 8‐week, double‐blind, randomized study to investigate the antihypertensive efficacy and safety of various nifedipine gastrointestinal treatment system (GITS)/candesartan cilexetil (N/C) dose combinations, vs respective monotherapies or placebo, in patients with diastolic blood pressure (DBP) ≥95 to <110 mm Hg. The current prespecified analysis compared BP reduction in participants with mild vs moderate baseline hypertension (ie, systolic [S]BP <160 mm Hg vs ≥160 mm Hg and DBP <100 mm Hg vs ≥100 mm Hg). A total of 1362 patients were analyzed by descriptive statistics. In all patient subgroups investigated, the NC combinations (ie, N: 20, 30, or 60 mg; C: 4, 8, 16, or 32 mg daily) provided greater SBP and DBP lowering and higher rates of BP control (defined as BP <140/90 mm Hg) than respective monotherapies or placebo, with greatest absolute BP reductions observed in the moderately elevated SBP or DBP subgroups. A trend to dose‐response relationship was observed in each subgroup. In each SBP and DBP subgroup, treatment‐related vasodilatory events (flushing, headache, or edema) were less frequent for patients receiving NC combination therapy than N monotherapy. These analyses support the use of calcium antagonist and angiotensin receptor blocker combination therapy in patients with both mild and moderate hypertension, for whom effective BP normalization and good drug tolerance would greatly reduce the risk of cardiovascular events.

Differential clinical profile of candesartan compared to other angiotensin receptor blockers

The advantages of blood pressure (BP) control on the risks of heart failure and stroke are well established. The renin-angiotensin system plays an important role in volume homeostasis and BP regulation and is a target for several groups of antihypertensive drugs. Angiotensin II receptor blockers represent a major class of antihypertensive compounds. Candesartan cilexetil is an angiotensin II type 1 (AT[1]) receptor antagonist (angiotensin receptor blocker [ARB]) that inhibits the actions of angiotensin II on the renin-angiotensin-aldosterone system. Oral candesartan 8–32 mg once daily is recommended for the treatment of adult patients with hypertension. Clinical trials have demonstrated that candesartan cilexetil is an effective agent in reducing the risk of cardiovascular mortality, stroke, heart failure, arterial stiffness, renal failure, retinopathy, and migraine in different populations of adult patients including patients with coexisting type 2 diabetes, metabolic syndrome, or kidney impairment. Clinical evidence confirmed that candesartan cilexetil provides better antihypertensive efficacy than losartan and is at least as effective as telmisartan and valsartan. Candesartan cilexetil, one of the current market leaders in BP treatment, is a highly selective compound with high potency, a long duration of action, and a tolerability profile similar to placebo. The most important and recent data from clinical trials regarding candesartan cilexetil will be reviewed in this article.

Candesartan cilexetil/hydrochlorothiazide combination treatment versus high-dose candesartan cilexetil monotherapy in patients with mild to moderate cardiovascular risk (CHILI Triple T)

BACKGROUND

Candesartan cilexetil has been shown to effectively reduce blood pressure and cardiovascular risk. Whether it is advantageous to combine candesartan cilexetil with low-dose hydrochlorothiazide (HCTZ) or uptitrate it in cases of insufficient blood pressure control has not been fully investigated under routine clinical conditions.

METHODS

CHILI Triple T is a prospective, noninterventional, observational study. Patients with uncontrolled hypertension and added cardiovascular risk received a fixed-dose combination of candesartan cilexetil 16 mg and HCTZ 12.5 mg (combination therapy group) or high-dose monotherapy with candesartan cilexetil 32 mg (high-dose monotherapy group).

RESULTS

A total of 4600 patients with a mean age of 63.1 ± 11.0 years, of which 44.7% were female, was included. The combination therapy group had 3337 patients, and the high-dose monotherapy group 1263 patients. Patients in both treatment groups were comparable with respect to age and gender, but patients receiving high-dose monotherapy had a slightly higher mean systolic blood pressure, more prior revascularizations, renal insufficiency, diabetic nephropathy, peripheral artery disease, and a lower ankle brachial index. The use of combination therapy resulted in a blood pressure reduction of -28.5 ± 13.8/-14.2 ± 9.4 mm Hg (P < 0.001 vs 160.2 ± 13.3/94.5 ± 8.2 mm Hg at baseline). The use of high-dose monotherapy reduced blood pressure by -29.73 ± 15.3/-14.1 ± 9.6 mm Hg (P < 0.001 vs 162.4 ± 14.7/94.7 ± 8.7 mm Hg at baseline). Differences in subgroups of patients defined by age, gender, body mass index, dyslipidemia, waist circumference, smoking, prior cardiovascular event, glomerular filtration rate, and microalbuminuria were minor, although partially significant. Tolerability was excellent, with only 28 out of 3358 patients (0.8%) in the combination therapy group and 15 out of 1273 patients (1.2%) in the high-dose monotherapy group experiencing any adverse event, of which one in each group was considered to be serious (<0.1%).

CONCLUSIONS

Both the fixed-dose combination of candesartan cilexetil 16 mg and HCTZ 12.5 mg and high-dose monotherapy with candesartan 32 mg were highly effective in lowering blood pressure in patients at increased cardiovascular risk. Tolerability was excellent. The choice of either strategy therefore largely depends on the principal aim: blood pressure reduction with pronounced volume restriction or pronounced additional end-organ protection.

Effect of candesartan cilexetil on diabetic and non-diabetic hypertensive patients: meta-analysis of five randomized double-blind clinical trials

OBJECTIVE

To study the effect of candesartan cilexetil (CC) in the management of blood pressure (BP) in diabetic and non-diabetic hypertensive patients.

METHODS

A selection of five randomized double-blind clinical trials in which patients were treated for hypertension with CC was analyzed. All of these were similar in design: i) a 4-week placebo run-in period, ii) a 4- to 6-week period (V1) with CC 8 mg once daily (od), after which the dosage was doubled if BP was not normalized (BP > 140/90 or BP >130/80 mmHg in diabetes), and iii) a 4- to 6-week period (V2) with CC 8 or 16 mg od. Efficacy was measured at V1 and V2.

RESULTS

702 patients were screened. The population consisted of 397 males (56.6%) with a mean age of 60 +/- 11 years, with 153 diabetic (21.8%) and 549 non-diabetic (78.2%) patients. At baseline, mean BP values were 160/94/65 mmHg for SPB, DBP, and pulse pressure (PP) respectively, with differences between diabetic and non-diabetic patients. SBP, DBP, and PP values showed a significant reduction at V1 (p < 0.001) and V2 (p < 0.001) compared with baseline for all hypertensive patients. Mean changes at V2 in SBP and PP values were higher in diabetic than non-diabetic patients (p < 0.001), and to a lesser degree on DBP values (p = 0.034).

CONCLUSIONS

CC was effective in lowering BP in diabetic and non-diabetic hypertensive patients. CC is a promising therapy to manage hypertensive diabetic patients, as demonstrated by the significant BP reduction.

A large scale study of angiotensin II inhibition therapy in an elderly population: the CHANCE study

This 8-week, multicenter study evaluated the efficacy and safety of candesartan cilexetil (CC, 8-16 mg) in elderly (>65 years) hypertensive patients. Patients (n=3013) received CC 8 mg during 8 weeks which eventually doubled to CC 16 mg at week 4 if blood pressure remained uncontrolled (> or = 140/90 mmHg). At week 8, 65.5% of patients were normalized (BP < 140/90 mmHg). Mean changes at week 8 were -25.8, -13.2, and -12.7 mmHg for systolic, diastolic, and pulse pressure, respectively. Age, sex, and diabetic status did not influence the antihypertensive effect of CC. 68% of the patients treated with, but uncontrolled or intolerant of, prior antihypertensive treatment were normalized by CC 8-16 mg. In summary, CC 8-16 mg once daily was effective and well tolerated in the management of arterial hypertension in elderly subjects.

Effect of candesartan, a type 1 angiotensin II receptor antagonist, on bronchial hyper-responsiveness to methacholine in patients with bronchial asthma

AIMS

Angiotensin II is a putative mediator in bronchial asthma. There have been very few studies investigating the involvement of angiotensin II receptors in bronchial hyper-responsiveness in asthmatic patients. We examined the effect of candesartan cilexetil, a specific angiotensin II type 1 (AT1) receptor antagonist, on bronchial responsiveness to inhaled methacholine in patients with asthma.

METHODS

Bronchial responsiveness to methacholine, assessed as the concentration of methacholine producing a 20% fall in FEV1 (PC20-FEV1), was measured on three occasions 2 weeks apart in 11 stable asthmatic patients. Candesartan cilexetil (8 mg once a day) or a placebo was orally administered for 1 week before the methacholine provocation test in a double-blind, randomized, crossover manner.

RESULTS

Although there were no significant differences between treatment periods in FEV1 values at baseline, the geometric mean (95% CI) PC20-FEV1 values increased significantly (P = 0.041) from 0.691 (0.379, 1.259) mg ml-1 with placebo to 0.837 (0.506, 1.384) mg ml-1 with candesartan. Candesartan decreased the mean (95% CI) arterial blood pressure (placebo: 95.6 (89.0, 102.2) mmHg, candesartan: 86.4 (79.8, 93.1) mmHg, P = 0.015). There was no correlation between the change in blood pressure and the change in PC20-FEV1.

CONCLUSIONS

We conclude that AT1 receptors are involved in bronchial hyper-responsiveness in asthmatic patients.

Use of angiotensin II receptor blockers alone and in combination with other drugs: a large clinical experience trial

Angiotensin II (Ang II) receptor blockers are the newest class of antihypertensive drugs to be developed. No large-scale clinical trials have been performed to evaluate their efficacy alone, or in combination with other drugs. A large-scale, eight week, open-label, non-placebo-controlled, single-arm trial evaluated the efficacy, tolerability and dose-response of candesartan cilexetil, 16-32 mg once-daily, either as monotherapy or as part of combination therapy, in a diverse hypertensive population in actual practice settings. 6465 patients with high blood pressure, of whom 52% were female and 16% African American, with a mean age of 58 years, were included. 5446 patients had essential hypertension and 1014 patients had isolated systolic hypertension. In order to be included in this study, patients had either untreated or uncontrolled hypertension (systolic blood pressure (SBP) 140-179 mmHg and/or diastolic blood pressure (DBP) 90-109 mmHg inclusive at baseline), despite a variety of other antihypertensive drugs. Of the 5156 patients with essential hypertension and at least one post baseline efficacy measurement, the mean pretreatment blood pressure (BP) was 156/97 mmHg. Candesartan cilexetil monotherapy reduced mean SBP/DBP by 18.0/12.2 mmHg. Similarly, in the 964 patients with isolated systolic hypertension and at least one post baseline efficacy measurement, candesartan cilexetil monotherapy reduced SBP/DBP from 158/81 by 16.5/4.5 mmHg. Candesartan cilexetil was similarly effective when employed as add-on therapy. When added to baseline antihypertensive medication in 51% of the patients with essential hypertension not achieving BP control, additional reduction in BP was achieved regardless of the background therapy, including diuretics (17.8/11.7 mmHg) calcium antagonists (16.6/11.2 mmHg), beta-blockers (16.5/10.4 mmHg), angiotensin-converting enzyme inhibitors (ACE-I) (15.3/10.0 mmHg), and alpha blockers (16.4/10.4 mmHg). Likewise, when candesartan cilexetil was used as add-on therapy in patients with isolated systolic hypertension, there was a consistent further reduction of mean SBP/DBP, regardless of the background therapy. Moreover, these monotherapeutic or add-on efficacy benefits were seen regardless of age (<65 or >65 years), gender, or race. Despite the open-label design of the study which enhances efficacy owing to the placebo effect, the Ang II receptor blocker, candesartan cilexetil either alone, or as an add-on therapy, is highly effective for assisting in the control of systolic and diastolic hypertension.

Pharmacokinetics and haemodynamics of candesartan cilexetil in hypertensive patients on regular haemodialysis

AIMS

The pharmacokinetic profile of candesartan cilexetil might be altered in patients with end-stage renal disease (ESRD). No data are available about the pharmacokinetics and haemodynamics of the angiotensin II receptor antagonist candesartan cilexetil in ESRD patients on regular haemodialysis (HD).

METHODS

We performed a repeated dose study (8 mg candesartan cilexetil once daily) in eight male HD patients over a treatment period of 5 days with an additional observation period of 3 days.

RESULTS

Pharmacokinetic analysis with nonlinear mixed effects modeling (NONMEM) over the whole treatment period revealed a dependency of the volume of distribution on body weight and of the metabolic clearance on age and body weight in the studied population. No significant drug elimination by HD was observed. The estimated metabolic and intercompartmental clearances were 83 ml min-1 (CV 39%) and 9.9 ml min-1, respectively. The unexplained random variability of the final two compartment model was 30%. In one patient with adult polycystic kidney disease oral clearance decreased during the observation period, attributable to a significant increase in bioavailability. Maximum observed changes in blood pressure were -50/-27+/-14/8 mmHg on day 5 with haemodialysis therapy as compared with changes in blood pressure of -14/-12+/-14/8 mmHg on day 1 without haemodialysis treatment. The observed maximum decrease in systolic blood pressure correlated with the amount of ultrafiltration during the HD session on day 5 (r=0.70, P<0.05). In two patients, one of whom was binephrectomized, severe hypotensive episodes were observed during this HD session.

CONCLUSIONS

HD does not influence the elimination kinetics of candesartan. The observed inter- and intraindividual variability of oral clearance and the pronounced influence of HD-induced volume contraction on the haemodynamic effects of candesartan makes it mandatory to carefully monitor HD patients treated with candesartan cilexetil.