Azilsartan Medoxomil targets the angiotensin II receptor type 1 (AT1). After hydrolysis to azilsartan, it acts as a potent and selective AT1 receptor antagonist. It has an IC50 of 0.62 nM for the AT1 receptor. Azilsartan lowers blood pressure by blocking the action of angiotensin II. It also inhibits the accumulation of AII-induced inositol 1-phosphate in cell-based assays with an IC50 of 9.2 nM.

Azilsartan medoxomil is a prodrug, which is rapidly converted to the active moiety, azilsartan (TAK-536), by ester hydrolysis in the gut and plasma during absorption after oral administration. Azilsartan selectively blocks the binding of angiotensin II to the AT1 (angiotensin II type 1) receptors found in the vascular smooth muscle and the adrenal gland, thereby promoting vasodilation and a decrease in the effects of aldosterone. Azilsartan is a highly selective antagonist to the AT1 receptor, with an IC50 of 2.6 nM, exhibiting a >10,000-fold affinity for the AT1 receptor compared with the AT2 receptor, and has not shown affinity for other cardiac receptors or ion channels. The inhibitory effect of Azilsartan persists after washout of the free compound (IC50 value of 7.4 nM). Azilsartan also inhibits the accumulation of angiotensin II -induced inositol 1-phosphate (IP1) in the cell-based assay with an IC50 value of 9.2 nM, and this effect is resistant to washout (IC50 value of 81.3 nM).
Kinase Assay: A radioligand binding assay is performed by using human AT1 receptor-coated microplates containing 4.4 to 6.2 fmol of receptors/well (10 μg of membrane protein/well). Membrane-coated wells are incubated with 45 μl of assay buffer (50 mM Tris-HCl, 5 mM MgCl2, 1 mM EDTA, and 0.005% CHAPS, pH 7.4) containing various concentrations of test compounds at room temperature. After 90 min, 5 μl of 125I-Sar1-Ile8-AII (final concentration 0.6 nM) dissolved in assay buffer is added to the wells, and the plate is incubated for 5 h. In each step, the plate is briefly and gently shaken on a plate shaker.
Cell Assay: Measurement of Inositol 1-Phosphate Accumulation. Twentyfour hours after transfections with human AT1-expressing plasmids, the cells are starved by changing the culture medium to starvation buffer (1 mM CaCl2, 0.5 mM MgCl2, 4.2 mM KCl, 146 mM NaCl, 5.5 mM glucose, and 10 mM HEPES, pH 7.3). Then, 5 μl/well of the test compounds dissolved in starvation buffer is added to the cells at the indicated concentrations, and they are pretreated for the indicated times. Two hours after starvation, LiCl is added to a final concentration of 50 mM with or without angiotensin II 10 nM, and the cells are further incubated for the indicated times at 37°C. In washout experiments, the cells are washed once with 100 μl/well of starvation buffer to remove unbound compounds before stimulation with angiotensin II. The accumulation of inositol 1-phosphate (IP1) is measured by using a IP-One Tb kit. The fluorescence resonance energy transfer signal is measured on a plate reader.
In vitro, Azilsartan Medoxomil acts as a potent angiotensin II type 1 (AT1) receptor antagonist. It inhibits the RAAS with an IC50 of 2.6 nM. It is over 10,000-fold more selective for the AT1 receptor compared to the AT2 receptor. In cell-based assays, it inhibits the accumulation of AII-induced inositol 1-phosphate with an IC50 of 9.2 nM.

In Koletsky rats, Azilsartan treatment lowers blood pressure, basal plasma insulin concentration and the homeostasis model assessment of insulin resistance index, and inhibited over-increase of plasma glucose and insulin concentrations during oral glucose tolerance test. Azilsartan downregulates 11β-hydroxysteroid dehydrogenase type 1 expression.

Non-cellular receptor binding assays for Azilsartan Medoxomil involve measuring its affinity for the AT1 receptor. These assays use membrane preparations from tissues expressing the AT1 receptor to study the displacement of a labeled angiotensin II ligand. The IC50 of 0.62 nM is a key parameter determined in these experiments. Such assays are essential for characterizing its potency and selectivity as an AT1 receptor antagonist.

In vitro cell-based assays for Azilsartan Medoxomil are used to study its functional effects. These assays often involve cells expressing the AT1 receptor, where the compound's ability to block angiotensin II-induced signaling, such as the accumulation of inositol 1-phosphate, is measured. These studies help to confirm its mechanism of action as an AT1 receptor antagonist at the cellular level.

Suspended in 5% Gum Arabic; 1, 2, and 3 mg/kg; Oral gavage
Male Wistar-Kyoto (WKY) rats, obese Koletsky (fak/fak) rats

Absorption, Distribution and Excretion
During absorption, azilsartan cilexetil is hydrolyzed to azilsartan. After oral administration, the parent drug is undetectable in plasma. The absolute bioavailability of azilsartan is estimated at 60%. The time to peak concentration (Tmax) is 1.5 to 3 hours. Steady-state plasma concentrations of azilsartan are reached within 5 days, and repeated once-daily dosing does not lead to plasma accumulation. Following oral administration of 14C-labeled azilsartan cilexetil, approximately 55% of the radioactive material is recovered in feces, and approximately 42% is recovered in urine. Of the dose recovered in urine, approximately 15% is excreted as azilsartan. The volume of distribution of azilsartan is approximately 16 liters. In rats, very small amounts of the radiolabeled drug cross the blood-brain barrier. Azilsartan can cross the placental barrier in pregnant rats and distribute to the fetus. The renal clearance of azilsartan is approximately 2.3 mL/min.

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Metabolism/Metabolites
Azilsartan ester is hydrolyzed into its active metabolite, which is further metabolized into two major metabolites, neither of which has pharmacological activity. The major metabolite in plasma is metabolite M-II, which is generated by an O-dealkylation reaction mediated by CYP2C9. The minor metabolite is metabolite MI, which is generated by decarboxylation reactions mediated by CYP2C8 and CYP2B6. The systemic exposure of azilsartan in MII is approximately 50%, while the systemic exposure of azilsartan in MI is less than 1%.

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Biological Half-Life
The elimination half-life of azilsartan is approximately 11 hours.
Azilsartan Medoxomil is an orally administered prodrug. It has a molecular weight of 568.53 g/mol. After oral administration, it is broken down to its active form, azilsartan. As an ARB, it is well-absorbed and has a pharmacokinetic profile suitable for once-daily dosing. Its half-life and other PK parameters are well-characterized in clinical settings.

Protein Binding
Azilsartan binds to human plasma proteins (primarily serum albumin) at a rate >99%. Even when plasma azilsartan concentrations are well above the recommended dose range, its protein binding remains constant.
Azilsartan Medoxomil has an established safety profile from its clinical use. It is generally well-tolerated, with side effects similar to other ARBs. As with all ARBs, it carries a risk of fetal toxicity if used during pregnancy. Comprehensive toxicological data are available from its clinical use. Azilsartan Medoxomil is an approved drug for the treatment of hypertension.

J Pharmacol Exp Ther.2011 Mar;336(3):801-8;Am J Hypertens.2007 May;20(5):579-86.

Pharmacodynamics
The pharmacodynamic effects of azilsartan cilexetil are mediated by its active metabolite, azilsartan. Azilsartan inhibits the pressor effect induced by angiotensin II infusion in a dose-dependent manner. A single 32 mg dose of azilsartan inhibits approximately 90% of the maximal pressor effect at peak plasma concentration and approximately 60% at 24 hours post-dose. In healthy subjects, single and repeated doses of azilsartan cilexetil resulted in increased plasma angiotensin I and II concentrations and plasma renin activity, while plasma aldosterone concentrations decreased. Like other angiotensin receptor blockers (ARBs), azilsartan dose-dependently reduces peripheral resistance and vascular smooth muscle tone. Because azilsartan blocks angiotensin II receptors, the negative feedback regulation of renin secretion by angiotensin II is inhibited; however, the resulting increase in plasma renin activity and circulating angiotensin II levels does not offset the antihypertensive effect of azilsartan. The antihypertensive effect of antihypertensive drugs may be diminished in African American patients. However, there are currently no recommendations to adjust azilsartan dosage based on patient sex, race, or the degree of renal or hepatic impairment. Azilsartan ester has negligible effects on serum potassium or sodium levels. Azilsartan does not affect angiotensin II biosynthesis or bradykinin levels. It also does not bind to any ion channels involved in cardiovascular regulation.
Azilsartan Medoxomil (TAK-491) is a potent, orally active prodrug that is hydrolyzed to the selective AT1 receptor antagonist azilsartan. It is used to treat essential hypertension and is highly selective for the AT1 receptor over the AT2 receptor. Azilsartan Medoxomil is an approved drug.

C30H24N4O8

568.53

568.159

C, 63.38; H, 4.26; N, 9.85; O, 22.51

863031-21-4

Azilsartan;147403-03-0;Azilsartan-d5;1346599-45-8;Azilsartan medoxomil monopotassium;863031-24-7

135409642

Solid powder

1.5±0.1 g/cm3

748.0±70.0 °C at 760 mmHg

406.2±35.7 °C

0.0±2.5 mmHg at 25°C

1.680

5.73

1

10

10

42

1100

0

O=C1OC(COC(C2C3=C(N=C(N3CC3C=CC(C4C(C5NC(=O)ON=5)=CC=CC=4)=CC=3)OCC)C=CC=2)=O)=C(C)O1

QJFSABGVXDWMIW-UHFFFAOYSA-N

InChI=1S/C30H24N4O8/c1-3-38-28-31-23-10-6-9-22(27(35)39-16-24-17(2)40-30(37)41-24)25(23)34(28)15-18-11-13-19(14-12-18)20-7-4-5-8-21(20)26-32-29(36)42-33-26/h4-14H,3,15-16H2,1-2H3,(H,32,33,36)

(5-methyl-2-oxo-1,3-dioxol-4-yl)methyl 2-ethoxy-1-((2-(5-oxo-2,5-dihydro-1,2,4-oxadiazol-3-yl)-[1,1-biphenyl]-4-yl)methyl)-1H-benzo[d]imidazole-7-carboxylate

TAK-491; TAK 491; TAK491; Azilsartan medoxomil; Azilsartan medoxomil potassium; trade name: Edarbi. Ipreziv.

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

Solubility in Formulation 1: ≥ 2.08 mg/mL (3.66 mM) (saturation unknown) in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 20.8 mg/mL clear DMSO stock solution to 400 μL PEG300 and mix evenly; then add 50 μL Tween-80 to the above solution and mix evenly; then add 450 μL normal saline to adjust the volume to 1 mL.
Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution.

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Solubility in Formulation 2: ≥ 2.08 mg/mL (3.66 mM) (saturation unknown) in 10% DMSO + 90% Corn Oil (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 20.8 mg/mL clear DMSO stock solution to 900 μL of corn oil and mix evenly.

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 (Please use freshly prepared in vivo formulations for optimal results.)