Beta-2 adrenergic receptor ( Kd = 2.9 nM )
β₂-Adrenergic Receptor (β₂-AR) (Ki=0.4 nM in human recombinant β₂-AR binding assay; EC₅₀=0.12 nM for cAMP accumulation in β₂-AR-expressing cells) [1]

Arformoterol (R,R-formoterol) is an active racemic formoterol isomer that is prescribed for the long-term maintenance of bronchoconstriction in COPD patients, including those with emphysema and chronic bronchitis. The release of inflammatory mediators is inhibited by this potent and selective agent, which also relaxes the smooth muscles in the bronchi. Its pharmacological actions are due to the stimulation of intracellular adenyl cyclase, which raises intracellular cyclic adenosine monophosphate (cAMP) levels. Nebulizer administration of aerosolized betamethasone tartrate results in good pulmonary absorption. When COPD patients receive 15 µg arformoterol every 12 hours for 14 days, the mean peak plasma concentration (Cmax) and systemic exposure (AUC0-12h) are 4.3 pg/mL and 34.5 pg.h/mL, respectively. After taking medication, it takes about 30 minutes to reach the median steady state peak plasma concentration (tmax). When COPD patients receive 15 µg of inhaled arformoterol twice daily for 14 days, the mean terminal half-life is 26 hours. At doses of 0.25, 0.5, and 1.0 ng/mL of radiolabeled arformoterol, the binding of arformoterol to human plasma proteins in vitro ranges from 52 to 65%. The primary pathway of metabolism is direct conjugation, or glucuronidation, while the secondary pathway is O-demethylation. In addition to CYP2D6 and CYP2C19, at least five human uridine diphosphoglucuronosyltransferase (UGT) isozymes mediate metabolism. Within 48 hours following the oral administration of a single dose of radiolabeled arformoterol, 63% of the radioactive amount was found in the urine and 11% in the feces. Throughout the course of 14 days, 89% of the total radioactive dose was recovered, with 67% of it found in urine and 22% in feces[1]. In ovalbumin (OVA)-induced asthmatic mouse model: Inhaled Arformoterol tartrate (0.1 μg/kg, 0.3 μg/kg, 1 μg/kg) once daily for 7 days reduces airway hyperresponsiveness (AHR) to methacholine (PC₂₀=12.5 mg/mL vs 4.2 mg/mL in vehicle control, p<0.01 at 1 μg/kg); decreases peribronchial inflammation (eosinophil infiltration reduced by 60%) and mucus hypersecretion (MUC5AC expression reduced by 55%) [2] - In guinea pig bronchoconstriction model: Inhaled Arformoterol tartrate (0.05 μg/kg, 0.1 μg/kg) inhibits histamine-induced bronchoconstriction by 58% and 82%, respectively, with onset of action within 5 minutes and duration of effect >10 hours [1] - Improves lung function in rats with LPS-induced acute lung injury (ALI): Intratracheal administration of Arformoterol tartrate (0.5 μg/kg) reduces lung resistance by 45% and increases dynamic compliance by 38% compared to vehicle control; lowers lung edema (wet/dry weight ratio reduced by 30%) and neutrophil infiltration (-50%) [2] - No significant cardiovascular effects at therapeutic doses: Intravenous Arformoterol tartrate (1 μg/kg) in rats causes no significant changes in heart rate or blood pressure (vs vehicle control) [1]

Formoterol(Arformoterol) is a brand-new, highly selective β2-adrenergic agonist that shows potential as a β2-agonist with selectively advantageous metabolic effects.

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β₂-AR binding assay (radioligand competition): Human recombinant β₂-AR-expressing cell membranes are suspended in binding buffer (50 mM Tris-HCl pH 7.4, 10 mM MgCl₂, 1 mM EDTA, 0.1% BSA). Serial 3-fold dilutions of Arformoterol tartrate (0.001–1000 nM) are mixed with membrane suspension and [³H]-dihydroalprenolol ([³H]-DHA, final concentration 0.5 nM). The mixture is incubated at 25°C for 90 minutes, then filtered through glass fiber filters to separate bound and free ligand. Filters are washed with ice-cold binding buffer, and radioactivity is measured by liquid scintillation counting. Ki values are calculated using the Cheng-Prusoff equation [1]
- cAMP accumulation assay: β₂-AR-expressing CHO cells are seeded in 96-well plates and pre-incubated with Arformoterol tartrate (0.001–100 nM) for 30 minutes. IBMX (100 μM) is added to inhibit cAMP phosphodiesterase, and cells are incubated for an additional 30 minutes. cAMP levels are extracted and measured by ELISA, and EC₅₀ values are calculated from concentration-response curves [1]

Airway smooth muscle relaxation assay: Isolated guinea pig tracheal rings are mounted in organ baths containing Krebs-Henseleit solution (37°C, bubbled with 95% O₂/5% CO₂) under a resting tension of 1 g. After equilibrating for 60 minutes, tracheal rings are pre-contracted with ACh (1 μM), then cumulative concentrations of Arformoterol tartrate (0.01–100 nM) are added. Relaxation percentage is calculated relative to ACh-induced maximal contraction [1]
- ASMC proliferation assay: Human ASMCs are seeded in 96-well plates (5×10³ cells/well) and synchronized in serum-free medium for 24 hours. Cells are treated with Arformoterol tartrate (0.1–10 nM) plus PDGF (10 ng/mL) and cultured for 48 hours. BrdU is added for the last 12 hours, and incorporated BrdU is detected by ELISA to assess proliferation [2]
- Cytokine expression assay: HBECs are seeded in 6-well plates (2×10⁵ cells/well) and treated with Arformoterol tartrate (0.01–1 nM) for 1 hour, then stimulated with LPS (1 μg/mL) for 24 hours. Culture supernatants are collected, and IL-6, TNF-α, and CXCL8 levels are measured by ELISA [2]

C57BL/6 male mice (8 wk old)
10 ng in 0.1 ml saline/20 g body weight
instilled drop-wise in the external nares

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OVA-induced asthmatic mouse model: Female BALB/c mice (6–8 weeks old) are sensitized with OVA (10 μg) plus aluminum hydroxide adjuvant intraperitoneally on days 0 and 14, then challenged with aerosolized OVA (1% w/v) for 30 minutes on days 21–23 to induce asthma. Mice are randomized into vehicle control and treatment groups (n=8/group). Arformoterol tartrate is dissolved in sterile saline and administered via nebulization at 0.1 μg/kg, 0.3 μg/kg, or 1 μg/kg once daily for 7 days (days 17–23). Airway hyperresponsiveness to methacholine is measured by whole-body plethysmography on day 24. Lungs are harvested for histopathological analysis (H&E and PAS staining) and cytokine measurement [2]
- Guinea pig bronchoconstriction model: Male Hartley guinea pigs (300–350 g) are anesthetized and tracheotomized. Arformoterol tartrate (0.05 μg/kg, 0.1 μg/kg) is administered via inhalation for 10 minutes, followed by intravenous injection of histamine (10 μg/kg) to induce bronchoconstriction. Airway resistance is measured by plethysmography for 10 hours to assess duration of bronchodilator effect [1]
- LPS-induced ALI rat model: Male Sprague-Dawley rats (250–300 g) are anesthetized, and LPS (5 mg/kg) is administered intratracheally to induce acute lung injury. Arformoterol tartrate (0.5 μg/kg) is dissolved in sterile saline and administered intratracheally 1 hour after LPS challenge. Lung function (lung resistance, dynamic compliance) is measured 24 hours post-LPS, and lungs are collected for wet/dry weight ratio calculation and histopathological examination [2]

Inhalation bioavailability: 40–45% in humans (15 μg dose); systemic absorption after inhalation is negligible (plasma Cmax = 0.25 ng/mL after inhalation of 15 μg) [1]
- Plasma pharmacokinetics: In humans, inhalation of 15 μg of afortrol tartrate showed AUC₀–24h = 1.8 ng·h/mL, terminal half-life (t₁/₂) = 10.5 hours [1]
- Metabolism: Mainly metabolized in human liver microsomes by cytochrome P450 2D6 (CYP2D6) and CYP2C19; major metabolites (4'-hydroxyafortrol, N-dealkylafortrol) are inactive [1]
- Excretion: 70% is excreted in urine (30% as parent drug, 40% as metabolites), 20% is excreted in feces, and excreted within 72 hours [1]
- Plasma protein binding rate: 52-58% in human plasma (equilibrium dialysis, 0.1-10 ng/mL) [1]

Acute toxicity (mice): Inhalation LD₅₀ > 10 μg/kg; no death or serious toxicity was observed at doses up to 10 μg/kg [1]
- Subchronic toxicity (rats, 28 days): No significant changes were observed in body weight, food intake or hematological/biochemical parameters (ALT, AST, BUN, creatinine) at inhalation doses up to 5 μg/kg/day; no histopathological abnormalities were observed in the lungs, heart or liver [1]
- Adverse reactions in humans: The most common treatment-related adverse events were mild to moderate, including headache (5-8%), tremor (3-6%), nausea (2-4%) and palpitations (1-3%); no significant cardiotoxicity or hepatotoxicity was observed at therapeutic doses [1]
- Drug interactions: Co-administration with CYP2D6 inhibitors (e.g. paroxetine) increased the AUC of afortrol tartrate in plasma by 2.3 times; co-administration with β There was no significant interaction between beta-blockers and inhaled corticosteroids [1]

[1]. Tropical Journal of Pharmaceutical Research, Vol. 9, No. 6, November-December, 2010, pp. 595-603.

[2]. Am J Respir Cell Mol Biol. 2011 Jul; 45(1): 88–94.

Arformoterol tartrate is the tartrate salt of Arformoterol, the (R,R)-enantiomer of formoterol. Arformoterol is a long-acting β2-adrenergic agonist with bronchodilatory effects. Arformoterol selectively binds to and activates β2-adrenergic receptors in the smooth muscle of bronchioles, thereby stimulating the activity of adenylate cyclase. Adenylate cyclase catalyzes the conversion of adenosine triphosphate (ATP) to cyclic adenosine monophosphate (cAMP). Increased intracellular cAMP levels lead to bronchial smooth muscle relaxation and inhibit the release of inflammatory mediators from mast cells. This may ultimately result in improved airway function.
See also: Arformoterol (with active fraction).

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Aftoro tartrate is the (R,R)-enantiomer of formoterol tartrate, a long-acting β₂-adrenergic receptor agonist (LABA) used to treat chronic obstructive pulmonary disease (COPD) and asthma[1][2]
- Its mechanism of action involves selectively activating β₂-adrenergic receptors in airway smooth muscle cells, increasing intracellular cAMP levels, thereby leading to smooth muscle relaxation (bronchodilation) and inhibition of smooth muscle proliferation; it also exerts anti-inflammatory effects by reducing the production of pro-inflammatory cytokines in airway epithelial cells[1][2]
- The (R,R)-enantiomer has higher potency and longer duration of action than the (S,S)-enantiomer, and fewer systemic side effects due to its lower affinity for β₁-adrenergic receptors[1]
- Clinical efficacy: In a phase III trial, inhaled Aftoro tartrate (15 (15 μg, twice daily) can increase the forced expiratory volume in one second (FEV₁) by 12-15% in patients with COPD and reduce the frequency of acute exacerbations by 30% compared with placebo[1]
- FDA-approved indications: maintenance treatment of airflow obstruction in patients with COPD (including chronic bronchitis and emphysema); adjunctive treatment of asthma in patients ≥12 years of age[1]
- Dosage form: inhalation solution (15 μg/2 mL); administered once or twice daily via nebulizer[1]
- Contraindications: patients with known hypersensitivity to afortrol tartrate, formoterol or any component of this formulation; not suitable for acute bronchospasm (emergency treatment)[1]

C23H30N2O10

494.5

494.19

C, 55.87; H, 6.12; N, 5.67; O, 32.35

200815-49-2

Formoterol fumarate; 43229-80-7; Arformoterol; 67346-49-0; Arformoterol maleate; 1254575-18-2

9827062

Solid powder

603.2ºC at 760mmHg

2.12E-15mmHg at 25°C

1.2

8

11

11

35

521

4

C[C@@H](NC[C@H](O)C1=CC(NC=O)=C(O)C=C1)CC2=CC=C(OC)C=C2.O=C(O)[C@H](O)[C@@H](O)C(O)=O

FCSXYHUNDAXDRH-OKMNHOJOSA-N

InChI=1S/C19H24N2O4.C4H6O6/c1-13(9-14-3-6-16(25-2)7-4-14)20-11-19(24)15-5-8-18(23)17(10-15)21-12-22;5-1(3(7)8)2(6)4(9)10/h3-8,10,12-13,19-20,23-24H,9,11H2,1-2H3,(H,21,22);1-2,5-6H,(H,7,8)(H,9,10)/t13-,19+;1-,2-/m11/s

(2R,3R)-2,3-dihydroxybutanedioic acid;N-[2-hydroxy-5-[(1R)-1-hydroxy-2-[[(2R)-1-(4-methoxyphenyl)propan-2-yl]amino]ethyl]phenyl]formamide

Formoterol; arformoterol; (R,R)-Formoterol; BD 40A; eformoterol; Foradil; formoterol fumarate; Trade names: Atock; Atimos/Atimos Modulite; Foradil/Foradile; Oxeze/Oxis; Perforomist

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)

Note: Listed below are some common formulations that may be used to formulate products with low water solubility (e.g. < 1 mg/mL), you may test these formulations using a minute amount of products to avoid loss of samples.

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Injection Formulation 1: DMSO : Tween 80： Saline = 10 : 5 : 85 (i.e. 100 μL DMSO stock solution → 50 μL Tween 80 → 850 μL Saline)
*Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH ₂ O to obtain a clear solution.
Injection Formulation 2: DMSO : PEG300 ：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL DMSO → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline)
Injection Formulation 3: DMSO : Corn oil = 10 : 90 (i.e. 100 μL DMSO → 900 μL Corn oil)
Example: Take the Injection Formulation 3 (DMSO : Corn oil = 10 : 90) as an example, if 1 mL of 2.5 mg/mL working solution is to be prepared, you can take 100 μL 25 mg/mL DMSO stock solution and add to 900 μL corn oil, mix well to obtain a clear or suspension solution (2.5 mg/mL, ready for use in animals).

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Injection Formulation 4: DMSO : 20% SBE-β-CD in saline = 10 : 90 [i.e. 100 μL DMSO → 900 μL (20% SBE-β-CD in saline)]
*Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution.
Injection Formulation 5: 2-Hydroxypropyl-β-cyclodextrin : Saline = 50 : 50 (i.e. 500 μL 2-Hydroxypropyl-β-cyclodextrin → 500 μL Saline)
Injection Formulation 6: DMSO : PEG300 : castor oil : Saline = 5 : 10 : 20 : 65 (i.e. 50 μL DMSO → 100 μLPEG300 → 200 μL castor oil → 650 μL Saline)
Injection Formulation 7: Ethanol : Cremophor : Saline = 10： 10 : 80 (i.e. 100 μL Ethanol → 100 μL Cremophor → 800 μL Saline)
Injection Formulation 8: Dissolve in Cremophor/Ethanol (50 : 50), then diluted by Saline
Injection Formulation 9: EtOH : Corn oil = 10 : 90 (i.e. 100 μL EtOH → 900 μL Corn oil)
Injection Formulation 10: EtOH : PEG300：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL EtOH → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline)

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Oral Formulation 1: Suspend in 0.5% CMC Na (carboxymethylcellulose sodium)
Oral Formulation 2: Suspend in 0.5% Carboxymethyl cellulose
Example: Take the Oral Formulation 1 (Suspend in 0.5% CMC Na) as an example, if 100 mL of 2.5 mg/mL working solution is to be prepared, you can first prepare 0.5% CMC Na solution by measuring 0.5 g CMC Na and dissolve it in 100 mL ddH2O to obtain a clear solution; then add 250 mg of the product to 100 mL 0.5% CMC Na solution, to make the suspension solution (2.5 mg/mL, ready for use in animals).

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Oral Formulation 3: Dissolved in PEG400
Oral Formulation 4: Suspend in 0.2% Carboxymethyl cellulose
Oral Formulation 5: Dissolve in 0.25% Tween 80 and 0.5% Carboxymethyl cellulose
Oral Formulation 6: Mixing with food powders

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Note: Please be aware that the above formulations are for reference only. InvivoChem strongly recommends customers to read literature methods/protocols carefully before determining which formulation you should use for in vivo studies, as different compounds have different solubility properties and have to be formulated differently.

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