H2 Receptor
H2 receptor (histamine H2 receptor).

With only a little amount of H1 activity and a significant selectivity towards H2 receptors, betzole (Ametazole) is a weak histamine agonist. The gastric inhibitory polypeptide (GIP) is secreted in response to betzole[1].

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Betazole is a selective H2 receptor agonist. It induces gastric acid secretion, resulting in an immediate and significant increase in common bile duct pressure. It is a weak histamine agonist with relative selectivity towards H2 receptors and only minimal H1 activity. Betazole induces gastric inhibitory polypeptide (GIP) secretion.

In vivo, betazole is used as a diagnostic agent called histalog to study the ability of the stomach to secrete acid. It stimulates gastric acid secretion and is used to detect maximal gastric acid secretion or anacidity. This test can be used to diagnose conditions such as Zollinger-Ellison syndrome.

In vitro receptor binding assays for betazole are performed to evaluate its affinity for the H2 receptor. Radioligand binding studies using membrane preparations from cells or tissues expressing the H2 receptor are conducted. The compound's ability to displace a specific radiolabeled H2 ligand is measured to calculate its binding affinity.

In vitro cell-based assays are conducted using cells expressing the H2 receptor. The cells are treated with betazole, and receptor activation is measured by assessing downstream signaling events such as cAMP accumulation. The potency and efficacy of the compound as an H2 agonist are determined from these functional assays.

In vivo studies are conducted in humans to evaluate the effects of betazole on gastric acid secretion. The compound is administered orally, and gastric acid output is measured to assess gastric secretory function. Betazole is used as a diagnostic agent to detect maximal gastric acid secretion or anacidity.

Absorption, distribution, and excretion are rapid and complete.

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Betazole is rapidly and completely absorbed, distributed, and excreted. It is orally bioactive and has a protein binding of 99%. Detailed pharmacokinetic parameters such as half-life and volume of distribution are not extensively documented in publicly available literature.

Protein Binding
99%

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Betazole is generally well-tolerated. It has the advantage of not causing side effects compared to histamine, eliminating the need for antihistamines. No specific toxicity data are publicly available.

[1]. Maples MD, Effects of betazole hydrochloride and cimetidine on common bile pressure and duodenal myoelectric activity in the dog. Am Surg. 1981;47(12):519-521.

[2]. Spitz IM, Betazole-induced GIP secretion is not mediated by gastric HCl. Metabolism. 1982;31(4):380-382.

[3]. CLAYMAN CB,. A simple oral gastric secretory stimulant (betazole hydrochloride). JAMA. 1961;175:908-909.

Betazole is a pyrazole compound in which a hydrogen atom flanking a nitrogen atom is replaced by a 2-aminoethyl group. It is a histamine H2 receptor agonist used clinically to assess gastric secretion function. It has dual uses as a histamine agonist, diagnostic reagent, and gastrointestinal medication. It belongs to the pyrazole class of compounds and is a primary amino compound.
A histamine H2 receptor agonist used for the clinical assessment of gastric secretion function.
Betazole is a histamine H2 receptor agonist with diagnostic applications. Betazole selectively targets and binds to H2 receptors, thereby mimicking the effects of histamine on these receptors. This may lead to increased gastric acid secretion. Betazole can be used for gastric function testing.
A histamine H2 receptor agonist used clinically to assess gastric secretion function.

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Drug Indications
For the clinical assessment of gastric secretion function.

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Mechanism of Action
Betazole is a histamine analog. It has the same effect as histamine, acting by binding to H2 receptors, which are mediators of gastric acid secretion. This agonist effect leads to an increase in gastric acid secretion.

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Pharmacodynamics
Betazol is a histamine H2 receptor agonist used to detect maximal gastric acid secretion or anacidity. This test can be used to diagnose conditions such as Zollinger-Ellison syndrome by measuring gastric acid secretion and basal secretion (more than 60% of the maximal acid secretion after betazol stimulation) after administration of betazol. Another test is to diagnose gastritis if gastric acid secretion is delayed and there is no response to betazol stimulation. Betazol can be used as a gastric secretion stimulant as an alternative to histamine, with the advantage of not causing side effects and therefore eliminating the need for antihistamines.

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Betazole (Ametazole, Histalog) is a pyrazole histamine analog and an orally bioactive H2 receptor agonist used clinically as a diagnostic agent to assess gastric secretory function. It induces gastric acid secretion and is used to detect maximal gastric acid secretion or anacidity. The compound is not intended for therapeutic use and is primarily a diagnostic reagent.

C5H9N3

111.15

111.08

105-20-4

Betazole dihydrochloride;138-92-1

7741

Colorless to light yellow ointment

1.14g/cm3

284.1ºC at 760mmHg

< 25 °C ; < 25 °C

150.3ºC

0.00303mmHg at 25°C

1.567

0.611

2

2

2

8

64.7

0

C(CN)C1=NNC=C1

JXDFEQONERDKSS-UHFFFAOYSA-N

InChI=1S/C5H9N3/c6-3-1-5-2-4-7-8-5/h2,4H,1,3,6H2,(H,7,8)

2-(1H-pyrazol-5-yl)ethanamine

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Note: This product requires protection from light (avoid light exposure) during transportation and storage.

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

DMSO: 250 mg/mL (2249.21 mM)

Solubility in Formulation 1: ≥ 2.08 mg/mL (18.71 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 (18.71 mM) (saturation unknown) in 10% DMSO + 90% (20% SBE-β-CD in 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 900 μL of 20% SBE-β-CD physiological saline solution and mix evenly.
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.

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Solubility in Formulation 3: ≥ 2.08 mg/mL (18.71 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.)