Absorption, Distribution and Excretion
Following inhalation, salbutamol acts topically on bronchial smooth muscle and the drug is initially undetectable in the blood. After 2 to 3 hours low concentrations are seen, due presumably to the portion of the dose which is swallowed and absorbed in the gut. In particular, the systemic levels of salbutamol are low after inhalation of recommended doses. A trial conducted in 12 healthy male and female subjects using a higher dose (1,080 mcg of albuterol base) showed that mean peak plasma concentrations of approximately 3 ng/mL occurred after dosing when salbutamol was delivered using propellant HFA-134a. The mean time to peak concentrations (Tmax) was delayed after administration of VENTOLIN (salbutamol) HFA (Tmax = 0.42 hours) as compared with CFC-propelled salbutamol inhaler (Tmax = 0.17 hours).
After oral administration, 58-78% of the dose is excreted in the urine in 24 hours, approximately 60% as metabolites. A small fraction is excreted in the feces.
The volume of distribution recorded for intravenously administered salbutamol has been recorded as 156 +/- 38 L.
The renal clearance of salbutamol has been documented as 272 +/- 38 ml/min after oral administration and 291 +/- 70 ml/min after intravenous administration. Furthermore, the renal clearance of the predominant sulfate conjugate metabolite was recorded as 98.5 +/- 23.5 ml/min following oral administration.
Elimination: Renal, 69 to 90% (60% as the metabolite). Fecal, 4%.
Extended-release tablets: Availability is approximately 80% of that for tablets after a single dose, regardless of whether or not taken with food, but is 100% of that for immediate-release tablets at steady-state. Food decreases the rate of absorption without affecting bioavailability.
Rapidly and well absorbed following oral administration.
Time to peak concentration: Syrup: within 2 hours. Tablets: 2 to 3 hours.
It is not known whether albuterol is distributed into human breast milk

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Metabolism / Metabolites
Salbutamol is not metabolized in the lung but is converted in the liver to the 4'-o-sulphate (salbutamol 4'-O-sulfate) ester, which has negligible pharmacologic activity. It may also be metabolized by oxidative deamination and/or conjugation with glucuronide. Salbutamol is ultimately excreted in the urine as free drug and as the metabolite.
Metabolized through sulfate conjugation to its inactive 4'-O-sulfate ester by phenol sulphotransferase (PST). The (R)-enantiomer of albuterol is preferentially metabolized (ten fold) by PST compared to the (S)-enantiomer of albuterol.
Hydrolyzed by esterases in tissue and blood to the active compound colterol. The drug is also conjugatively metabolized to salbutamol 4'-O-sulfate.
Route of Elimination: Approximately 72% of the inhaled dose is excreted in the urine within 24 hours, 28% as unchanged drug and 44% as metabolite.
Half Life: 1.6 hours

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Biological Half-Life
The elimination half-life of inhaled or oral salbutamol has been recorded as being between 2.7 and 5 hours while the apparent terminal plasma half-life of albuterol has been documented as being approximately 4.6 hours.
Elimination: 3.8 to 6 hours.

Effects During Pregnancy and Lactation
◉ Summary of Use during Lactation
Although no published data exist on the use of albuterol by mouth or inhaler during lactation, data from the related drug, terbutaline, indicate that very little is expected to be excreted into breastmilk. The authors of several reviews and expert guidelines agree that use of inhaled bronchodilators is acceptable during breastfeeding because of the low bioavailability and maternal serum levels after use.
◉ Effects in Breastfed Infants
Relevant published information was not found as of the revision date.
◉ Effects on Lactation and Breastmilk
Relevant published information was not found as of the revision date.
◈ What is albuterol?
Albuterol (also called salbutamol) is a medication used for the treatment of asthma. It is in a class of medications called beta2-agonists. Beta2-agonists are called bronchodilators, meaning that they help to open the airways in the lungs. Albuterol is used in fast-acting inhalers for treatment of asthma. Some brand names are Asmavent®, Asmol® Proventil®, Respax®, Respolin®, Salamol®, Salbulin®, Salbuvent® and Ventolin®.Sometimes when people find out they are pregnant, they think about changing how they take their medication, or stopping their medication altogether. However, it is important to talk with your healthcare providers before making any changes to how you take this medication. Your healthcare providers can talk with you about the benefits of treating your condition and the risks of untreated illness during pregnancy. Untreated asthma increases the chance for complications for both the person who is pregnant and the baby. For more information, please see the MotherToBaby fact sheet on Asthma at https://mothertobaby.org/fact-sheets/asthma-and-pregnancy/.
◈ I take albuterol. Can it make it harder for me to get pregnant?
It is not known if albuterol can make it harder to get pregnant. Animal studies have shown no effect on fertility.
◈ Does taking albuterol increase the chance for miscarriage?
Miscarriage is common and can occur in any pregnancy for many different reasons. It is not known if albuterol increases the chance for miscarriage.
◈ Does taking albuterol increase the chance of birth defects?
Every pregnancy starts out with a 3-5% chance of having a birth defect. This is called the background risk. Although data is limited, studies do not suggest an increased chance for birth defects with the use of inhaled albuterol during pregnancy.One study looked at the use of five different inhaled beta2-agonist bronchodilators in the first trimester of pregnancy. This study did not find an increase in the number of birth defects with use of any of these medications. Of the 259 people who were pregnant in this study, 20 of them took albuterol. Another study found a link between albuterol use and several types of birth defects. However, this study could not rule out the influence of asthma. Other studies do not support the suggestion that albuterol causes an increased chance for a pattern of birth defects.Albuterol is considered a good medication to be used for asthma when a fast-acting inhaler is needed for immediate symptoms. It is important to treat asthma during pregnancy. Because albuterol is inhaled, it is absorbed into the body in lower amounts compared to pill / tablet forms of the medication. It is unknown how much, if any, of the medication reaches the developing baby. Research suggests that the amount is likely small. Use of a fast-acting albuterol inhaler more than two days per week can be a sign that asthma symptoms may not be well controlled. If so, talk with your healthcare provider about the best way to treat your asthma.
◈ Does taking albuterol in pregnancy increase the chance of other pregnancy-related problems?
Albuterol has been used in the second and third trimester of pregnancy to prevent preterm delivery (delivery before 37 weeks of pregnancy). For treatment of preterm delivery, albuterol was given in high oral doses (by mouth). Treatment with high oral doses has been associated with an increase in maternal and fetal heart rate and a drop in maternal blood pressure. These effects are temporary. Long term effects from increased fetal heart rate have not been reported. Treatment with inhaled albuterol at prescribed doses has not been shown to cause these effects.
◈ Does taking albuterol in pregnancy affect future behavior or learning for the child?
It is not known if albuterol can cause behavior or learning issues.
◈ Breastfeeding while taking albuterol:
There have not been any studies of people taking albuterol while breastfeeding. However, using an albuterol inhaler is not thought to cause high enough levels in the person’s bloodstream to pass into breast milk in large amounts. Inhaled bronchodilators are generally considered acceptable for use during breastfeeding. Be sure to talk to your healthcare provider about all your breastfeeding questions.
◈ If a male takes albuterol, could it affect fertility (ability to get partner pregnant) or increase the chance of birth defects?
There are no data to suggest that a father’s or sperm donor’s use of albuterol at the time of conception increases the chance for birth defects. In general, exposures that fathers or sperm donors have are unlikely to increase the risks to a pregnancy. For more information, please see the MotherToBaby fact sheet about Paternal Exposures at https://mothertobaby.org/fact-sheets/paternal-exposures-pregnancy/.

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Protein Binding
Salbutamol is only weakly bound to plasma proteins.

Clin Sci (Lond).1986 Feb;70(2):159-65.

Albuterol is a member of the class of phenylethanolamines that is 4-(2-amino-1-hydroxyethyl)-2-(hydroxymethyl)phenol having a tert-butyl group attached to the nirogen atom. It acts as a beta-adrenergic agonist used in the treatment of asthma and chronic obstructive pulmonary disease (COPD). It has a role as a bronchodilator agent, a beta-adrenergic agonist, an environmental contaminant and a xenobiotic. It is a member of phenylethanolamines, a secondary amino compound and a member of phenols.
Salbutamol is a short-acting, selective beta2-adrenergic receptor agonist used in the treatment of asthma and COPD. It is 29 times more selective for beta2 receptors than beta1 receptors giving it higher specificity for pulmonary beta receptors versus beta1-adrenergic receptors located in the heart. Salbutamol is formulated as a racemic mixture of the R- and S-isomers. The R-isomer has 150 times greater affinity for the beta2-receptor than the S-isomer and the S-isomer has been associated with toxicity. This lead to the development of levalbuterol, the single R-isomer of salbutamol. However, the high cost of levalbuterol compared to salbutamol has deterred wide-spread use of this enantiomerically pure version of the drug. Salbutamol is generally used for acute episodes of bronchospasm caused by bronchial asthma, chronic bronchitis and other chronic bronchopulmonary disorders such as chronic obstructive pulmonary disorder (COPD). It is also used prophylactically for exercise-induced asthma.
Albuterol is a beta2-Adrenergic Agonist. The mechanism of action of albuterol is as an Adrenergic beta2-Agonist.
Albuterol is a racemic mixture of the r-isomer levalbuterol and s-albuterol, a short-acting sympathomimetic agent with bronchodilator activity. Albuterol stimulates beta-2 adrenergic receptors in the lungs, thereby activating the enzyme adenylate cyclase that catalyzes the conversion of adenosine triphosphate (ATP) to cyclic-3',5'-adenosine monophosphate (cAMP). Increased cAMP concentrations relax bronchial smooth muscle, relieve bronchospasms, and reduce inflammatory cell mediator release, especially from mast cells. Albuterol although to a lesser extent, also stimulates beta-1 adrenergic receptors, thereby increasing the force and rate of myocardial contraction.
Salbutamol is a short-acting, selective beta2-adrenergic receptor agonist used in the treatment of asthma and COPD. It is 29 times more selective for beta2 receptors than beta1 receptors giving it higher specificity for pulmonary beta receptors versus beta1-adrenergic receptors located in the heart. Salbutamol is formulated as a racemic mixture of the R- and S-isomers. The R-isomer has 150 times greater affinity for the beta2-receptor than the S-isomer and the S-isomer has been associated with toxicity. This lead to the development of levalbuterol, the single R-isomer of salbutamol. However, the high cost of levalbuterol compared to salbutamol has deterred wide-spread use of this enantiomerically pure version of the drug. Salbutamol is generally used for acute episodes of bronchospasm caused by bronchial asthma, chronic bronchitis and other chronic bronchopulmonary disorders such as chronic obstructive pulmonary disorder (COPD). It is also used prophylactically for exercise-induced asthma.
A short-acting beta-2 adrenergic agonist that is primarily used as a bronchodilator agent to treat ASTHMA. Albuterol is prepared as a racemic mixture of R(-) and S(+) stereoisomers. The stereospecific preparation of R(-) isomer of albuterol is referred to as levalbuterol.
See also: Albuterol Sulfate (active moiety of).

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Drug Indication
Salbutamol is indicated for (i) the symptomatic relief and prevention of bronchospasm due to bronchial asthma, chronic bronchitis, reversible obstructive airway disease, and other chronic bronchopulmonary disorders in which bronchospasm is a complicating factor, and/or (ii) the acute prophylaxis against exercise-induced bronchospasm and other stimuli known to induce bronchospasm.
FDA Label

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Mechanism of Action
In vitro studies and in vivo pharmacologic studies have shown that salbutamol has a preferential effect on beta2-adrenergic receptors compared with isoproterenol. Although beta2­ adrenoceptors are the predominant adrenergic receptors in bronchial smooth muscle and beta1 adrenoceptors are the predominant receptors in the heart, there are also beta2-adrenoceptors in the human heart comprising 10% to 50% of the total beta-adrenoceptors. The precise function of these receptors has not been established, but their presence raises the possibility that even selective beta2-agonists may have cardiac effects. Activation of beta2-adrenergic receptors on airway smooth muscle leads to the activation of adenyl cyclase and to an increase in the intracellular concentration of cyclic-3′,5′-adenosine monophosphate (cyclic AMP). This increase of cyclic AMP leads to the activation of protein kinase A, which inhibits the phosphorylation of myosin and lowers intracellular ionic calcium concentrations, resulting in relaxation. Salbutamol relaxes the smooth muscles of all airways, from the trachea to the terminal bronchioles. Salbutamol acts as a functional antagonist to relax the airway irrespective of the spasmogen involved, thus protecting against all bronchoconstrictor challenges. Increased cyclic AMP concentrations are also associated with the inhibition of release of mediators from mast cells in the airway. Salbutamol has been shown in most controlled clinical trials to have more effect on the respiratory tract, in the form of bronchial smooth muscle relaxation, than isoproterenol at comparable doses while producing fewer cardiovascular effects. Controlled clinical studies and other clinical experience have shown that inhaled albuterol, like other beta-adrenergic agonist drugs, can produce a significant cardiovascular effect in some patients, as measured by pulse rate, blood pressure, symptoms, and/or electrocardiographic changes. A measurable decrease in airway resistance is typically observed within 5 to 15 minutes after inhalation of salbutamol. The maximum improvement in pulmonary function usually occurs 60 to 90 minutes after salbutamol treatment, and significant bronchodilator activity has been observed to persist for 3 to 6 hours.
Adrenergic bronchodilators act by stimulating beta2-adrenergic receptors in the lungs to relax bronchial smooth muscle, thereby relieving bronchospasm. /Adrenergic bronchodilators/
Primarily stimulates beta2-adrenergic receptors, with some minor beta1-adrenergic activity.
In vitro studies and in vivo pharmacologic studies have demonstrated that albuterol has a preferential effect on beta2-adrenergic receptors compared with isoproterenol. While it is recognized that beta2-adrenergic receptors are the predominant receptors in bronchial smooth muscle, date indicate that there is a population of beta2-receptors in the human heart existing in a concentration between 10% and 50% of cardiac beta-adrenergic receptors. The precise function of these receptors has not been established.
Activation of beta2-adrenergic receptors on airway smooth muscle leads to the activation of adenylcyclase and to an increase in the intracellular concentration of cyclic-3',5'-adenosine monophosphate (cyclic AMP). This increase of cyclic AMP leads to the activation of protein kinase A, which inhibits the phosphorylation of myosin and lowers intracellular ionic calcium concentrations, resulting in relaxation. Albuterol relaxes the smooth muscles of all airways, from the trachea to the terminal bronchioles. Albuterol acts as a functional antagonist to relax the airway irrespective of the spasmogen involved, this protecting against all bronchoconstrictor challenges. Increased cyclic AMP concentrations are also associated with the inhibition of release of mediators from most cells in the airway.

C13H21NO3

239.31

239.152

18559-94-9

Salbutamol hemisulfate;51022-70-9;Salbutamol-d3;1219798-60-3;Salbutamol-d9;1173021-73-2;Salbutamol-d9 acetate;1781417-68-2

2083

White to off-white solid powder

1.2±0.1 g/cm3

433.5±40.0 °C at 760 mmHg

157-158ºC

159.5±17.9 °C

0.0±1.1 mmHg at 25°C

1.566

0.01

72.72

4

4

5

17

227

0

NDAUXUAQIAJITI-UHFFFAOYSA-N

NDAUXUAQIAJITI-UHFFFAOYSA-N

4-[2-(tert-butylamino)-1-hydroxyethyl]-2-(hydroxymethyl)phenol

Salbutamol Albuterol Proventil Sultanol Aerolin Albuterol Sulfate Proventil Salbutamol Sultanol Ventolin

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)

DMSO : ~100 mg/mL (~417.87 mM)

配方 1 中的溶解度: ≥ 2.5 mg/mL (10.45 mM) (饱和度未知) in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% Saline (这些助溶剂从左到右依次添加，逐一添加), 澄清溶液。
例如，若需制备1 mL的工作液，可将100 μL 25.0 mg/mL澄清DMSO储备液加入到400 μL PEG300中，混匀；然后向上述溶液中加入50 μL Tween-80，混匀；加入450 μL生理盐水定容至1 mL。
*生理盐水的制备：将 0.9 g 氯化钠溶解在 100 mL ddH₂O中，得到澄清溶液。

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配方 2 中的溶解度: ≥ 2.5 mg/mL (10.45 mM) (饱和度未知) in 10% DMSO + 90% (20% SBE-β-CD in Saline) (这些助溶剂从左到右依次添加，逐一添加), 澄清溶液。
例如，若需制备1 mL的工作液，可将 100 μL 25.0 mg/mL澄清DMSO储备液加入900 μL 20% SBE-β-CD生理盐水溶液中，混匀。
*20% SBE-β-CD 生理盐水溶液的制备（4°C，1 周）：将 2 g SBE-β-CD 溶解于 10 mL 生理盐水中，得到澄清溶液。

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配方 3 中的溶解度: ≥ 2.5 mg/mL (10.45 mM) (饱和度未知) in 10% DMSO + 90% Corn Oil (这些助溶剂从左到右依次添加，逐一添加), 澄清溶液。
例如，若需制备1 mL的工作液，可将 100 μL 25.0 mg/mL 澄清 DMSO 储备液加入到 900 μL 玉米油中并混合均匀。

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请根据您的实验动物和给药方式选择适当的溶解配方/方案：
1、请先配制澄清的储备液(如：用DMSO配置50 或 100 mg/mL母液(储备液));
2、取适量母液，按从左到右的顺序依次添加助溶剂，澄清后再加入下一助溶剂。以 下列配方为例说明 (注意此配方只用于说明，并不一定代表此产品 的实际溶解配方):
10% DMSO → 40% PEG300 → 5% Tween-80 → 45% ddH2O (或 saline);
假设最终工作液的体积为 1 mL, 浓度为5 mg/mL: 取 100 μL 50 mg/mL 的澄清 DMSO 储备液加到 400 μL PEG300 中，混合均匀/澄清；向上述体系中加入50 μL Tween-80，混合均匀/澄清；然后继续加入450 μL ddH2O (或 saline)定容至 1 mL；
3、溶剂前显示的百分比是指该溶剂在最终溶液/工作液中的体积所占比例;
4、 如产品在配制过程中出现沉淀/析出，可通过加热(≤50℃)或超声的方式助溶;
5、为保证最佳实验结果，工作液请现配现用！
6、如不确定怎么将母液配置成体内动物实验的工作液，请查看说明书或联系我们;
7、 以上所有助溶剂都可在 Invivochem.cn网站购买。