| Size | Price | Stock | Qty |
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| 5mg |
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| 10mg |
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| Other Sizes |
| Targets |
Betazole hydrochloride targets the histamine H2 receptor (H2R), a G protein-coupled receptor located on the parietal cells of the stomach. As a selective H2 receptor agonist, betazole binds to and activates H2 receptors, mimicking the effect of endogenous histamine. This activation stimulates the proton pump (H+/K+ ATPase) via the cAMP-dependent pathway, leading to increased gastric acid secretion. Unlike histamine, betazole has minimal effects on H1 receptors, resulting in fewer allergic-type side effects such as hypotension or bronchospasm, though it retains the ability to elevate common bile duct pressure.
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| ln Vitro |
In vitro, betazole hydrochloride acts as an H2 receptor agonist, with studies showing it induces histamine-like responses in isolated gastric mucosa preparations, stimulating acid secretion in a concentration-dependent manner. Compared to histamine, betazole exhibits a slower onset but more prolonged duration of action in stimulating acid output. In isolated guinea pig atria, betazole shows weak positive chronotropic effects (H2-mediated), confirming its receptor selectivity. Betazole also relaxes the gallbladder and biliary sphincter in vitro, facilitating bile flow. The compound is used in pharmacological studies as a reference H2 agonist, particularly for comparing the potency of H2 antagonists.
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| ln Vivo |
In vivo, betazole hydrochloride (formerly marketed as Histalog) was administered orally or intramuscularly to evaluate gastric secretory function in patients with suspected gastric disorders such as peptic ulcers, Zollinger-Ellison syndrome, and pernicious anemia. The standard diagnostic dose was 50 mg (oral) or 50 mg (IM), with gastric juice collected over 60-90 minutes. Betazole induces a dose-dependent increase in gastric acid output, with maximal acid secretion (peak acid output, PAO) occurring within 45-60 minutes. It also increases common bile duct pressure, making it useful for assessing biliary dyskinesia. Betazole stimulation is considered safer than histamine due to reduced cardiovascular effects.
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| Enzyme Assay |
In vitro H2 receptor binding can be assessed using radioligand binding assays. Membranes prepared from cells expressing human H2 receptors (e.g., CHO-H2R cells) are incubated with [3H]-tiotidine (an H2 antagonist) and varying concentrations of betazole hydrochloride (1 nM - 100 microM) in binding buffer. After incubation, bound radioactivity is separated by filtration, and IC₅0 values are calculated. Alternatively, functional activity can be measured via cAMP accumulation: cells expressing H2 receptors are treated with betazole (0.1 - 100 microM), and intracellular cAMP levels are quantified using ELISA or HTRF assays, from which EC₅0 values are derived.
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| Cell Assay |
For functional studies, gastric parietal cells (e.g., isolated from rabbit or rat stomach) are seeded in 96-well plates and treated with betazole hydrochloride (1 - 1000 microM) for 30-60 minutes. Acid secretion is measured by the accumulation of 14C-aminopyrine (AP) within cells, which correlates with H+ production. Cells are incubated with [14C]-aminopyrine (0.2 microCi/mL) and test compound, then lysed, and radioactivity quantified by scintillation counting. EC₅0 values for acid secretion are calculated from dose-response curves. Histamine (1-100 microM) serves as a positive control. Cytotoxicity is assessed by LDH release or MTT assay in parallel to ensure effects are not due to cell damage.
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| Animal Protocol |
In vivo gastric acid secretion studies are conducted in male Sprague-Dawley rats (200-250 g) following pylorus ligation. Under anesthesia, the pylorus is ligated, and betazole hydrochloride (5-50 mg/kg) is administered intraperitoneally or intraduodenally. After 2-4 hours, gastric juice is collected, and volume and acidity are measured by titration with 0.1 N NaOH. In dogs (mongrel, 15-20 kg), betazole (0.5-2 mg/kg IV) is administered via intravenous injection, and gastric juice is collected via a gastric cannula at 15-minute intervals for 2 hours. Total acid output (mEq/h) is calculated. Positive control: histamine (0.01 mg/kg IV). Betazole induces a more prolonged acid secretory response compared to histamine.
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| ADME/Pharmacokinetics |
Betazole hydrochloride is rapidly absorbed following oral administration, with peak plasma concentrations occurring within 30-60 minutes. The plasma half-life in humans is approximately 45-60 minutes. Betazole is metabolized primarily in the liver, likely via deamination and oxidation, and is excreted in the urine as metabolites and unchanged drug. Unlike histamine, betazole has no significant first-pass metabolism. Bioavailability after oral dosing is approximately 50-75%. Protein binding is low. The compound has a volume of distribution (Vd) consistent with extracellular fluid. For diagnostic use, a single oral dose of 50 mg produces gastric acid stimulation for up to 90 minutes.
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| Toxicity/Toxicokinetics |
For betazole hydrochloride, acute oral LD₅0 in rats is approximately 300-500 mg/kg. In diagnostic use, adverse effects are generally mild and include nausea, abdominal discomfort, flushing, and headache. At high doses, betazole can cause hypotension and tachycardia due to H2-mediated vasodilation, though these effects are less severe than with histamine. Betazole is contraindicated in patients with a history of severe cardiovascular disease, known hypersensitivity, or Zollinger-Ellison syndrome (may exacerbate symptoms). Overdose may lead to severe hypotension, arrhythmias, and metabolic alkalosis due to excessive acid secretion. For research use, standard safety precautions apply: use PPE (gloves, lab coat, goggles), work in a fume hood, avoid inhalation and skin contact.
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| References |
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| Additional Infomation |
Betazole hydrochloride is the hydrochloride form of betazole, a histamine H2 receptor agonist with diagnostic applications. Betazole selectively targets and binds to H2 receptors, thus mimicking the effects of histamine on these receptors. This may lead to increased gastric acid secretion. Betazole can be used for gastric function tests.
Betazole hydrochloride (Ametazole hydrochloride; Histalog; CAS# 1121-45-5) is a research-grade histamine H2 receptor agonist. It is not an FDA-approved drug for contemporary use (histamine phosphate replaced betazole in clinical practice). Betazole hydrochloride is used as a reference standard for H2 receptor pharmacology, as a positive control in acid secretion studies, and as a chemical tool for investigating H2 receptor-mediated signaling. For research use only, not for diagnostic or therapeutic applications. Storage: powder at -20degC, protected from light and moisture. |
| Molecular Formula |
C5H10CLN3
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|---|---|
| Molecular Weight |
147.61
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| Exact Mass |
147.056
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| CAS # |
1121-45-5
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| Related CAS # |
Betazole; Betazole dihydrochloride; Betazole; 105-20-4
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| PubChem CID |
16051987
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| Appearance |
Solid powder
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| Hydrogen Bond Donor Count |
3
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| Rotatable Bond Count |
2
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| Heavy Atom Count |
9
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| Complexity |
64.7
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| Defined Atom Stereocenter Count |
0
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| SMILES |
C1=C(NN=C1)CCN.Cl
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| InChi Key |
HLJRAERMLKNULP-UHFFFAOYSA-N
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| InChi Code |
InChI=1S/C5H9N3.ClH/c6-3-1-5-2-4-7-8-5;/h2,4H,1,3,6H2,(H,7,8);1H
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| Chemical Name |
2-(1H-pyrazol-5-yl)ethanamine;hydrochloride
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| Synonyms |
Ametazole hydrochloride
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| HS Tariff Code |
2934.99.9001
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| Storage |
Powder -20°C 3 years 4°C 2 years In solvent -80°C 6 months -20°C 1 month |
| Shipping Condition |
Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)
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| Solubility (In Vitro) |
May dissolve in DMSO (in most cases), if not, try other solvents such as H2O, Ethanol, or DMF with a minute amount of products to avoid loss of samples
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| Solubility (In Vivo) |
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.
Injection Formulations
Injection Formulation 1: DMSO : Tween 80： Saline = 10 : 5 : 85 (i.e. 100 μL DMSO stock solution → 50 μL Tween 80 → 850 μL Saline)(e.g. IP/IV/IM/SC) *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). View More
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)] Oral Formulations
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). View More
Oral Formulation 3: Dissolved in PEG400 (Please use freshly prepared in vivo formulations for optimal results.) |
| Preparing Stock Solutions | 1 mg | 5 mg | 10 mg | |
| 1 mM | 6.7746 mL | 33.8730 mL | 67.7461 mL | |
| 5 mM | 1.3549 mL | 6.7746 mL | 13.5492 mL | |
| 10 mM | 0.6775 mL | 3.3873 mL | 6.7746 mL |
*Note: Please select an appropriate solvent for the preparation of stock solution based on your experiment needs. For most products, DMSO can be used for preparing stock solutions (e.g. 5 mM, 10 mM, or 20 mM concentration); some products with high aqueous solubility may be dissolved in water directly. Solubility information is available at the above Solubility Data section. Once the stock solution is prepared, aliquot it to routine usage volumes and store at -20°C or -80°C. Avoid repeated freeze and thaw cycles.
Calculation results
Working concentration： mg/mL；
Method for preparing DMSO stock solution： mg drug pre-dissolved in μL DMSO (stock solution concentration mg/mL). Please contact us first if the concentration exceeds the DMSO solubility of the batch of drug.
Method for preparing in vivo formulation:：Take μL DMSO stock solution, next add μL PEG300, mix and clarify, next addμL Tween 80, mix and clarify, next add μL ddH2O，mix and clarify.
(1) Please be sure that the solution is clear before the addition of next solvent. Dissolution methods like vortex, ultrasound or warming and heat may be used to aid dissolving.
(2) Be sure to add the solvent(s) in order.
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