Acepromazine maleate targets dopamine receptors in the central nervous system as an antagonist. It is a phenothiazine antipsychotic drug that blocks dopamine D2 receptors. By antagonizing dopamine receptors, acepromazine maleate causes sedation, muscular relaxation, and a reduction in spontaneous activity. It also has antiemetic effects. The compound's mechanism is similar to other phenothiazine antipsychotics.

In vitro, acepromazine maleate has been characterized as a dopamine receptor antagonist. Its activity at dopamine D2 receptors has been confirmed in receptor binding and functional assays. The compound's ability to block dopamine-mediated signaling contributes to its sedative and antipsychotic effects. The maleate salt form does not significantly alter the pharmacological activity compared to the base compound.

In vivo, acepromazine maleate causes sedation, muscular relaxation, and a reduction in spontaneous activity in animals. It is frequently used in veterinary medicine as a sedative and antiemetic. The drug's sedative effects are mediated through dopamine receptor antagonism in the CNS. It is used to calm anxious or aggressive animals and as a pre-anesthetic agent.

In non-cell-based receptor binding assays, acepromazine maleate's affinity for dopamine receptors is evaluated using radioligand competition binding experiments. Membrane preparations from cells expressing dopamine D2 receptors are incubated with a radiolabeled D2-selective ligand and varying concentrations of acepromazine maleate. After incubation, bound and free radioligand are separated, and radioactivity is measured. Competition curves are generated to determine IC50 and Ki values.

In vitro cellular assays for acepromazine maleate involve measuring its antagonist activity at dopamine receptors in cultured cells. Cells expressing dopamine D2 receptors are treated with acepromazine maleate in the presence of a dopamine agonist, and receptor activation is assessed by measuring downstream signaling such as cAMP accumulation. The compound's ability to inhibit agonist-induced signaling is quantified to confirm its antagonist activity.

In vivo animal studies for acepromazine maleate are conducted primarily in veterinary species. The compound is administered via oral, intramuscular, or intravenous routes, and its sedative and antiemetic effects are assessed. Behavioral observations, physiological measurements, and clinical evaluations are used to assess the drug's efficacy and safety. Acepromazine maleate is frequently used in dogs, cats, and horses.

The biological half-life is 3 hours in horses.
Acepromazine maleate is well absorbed after administration and is distributed throughout the body, including the central nervous system. It is metabolized in the liver and eliminated primarily by renal excretion. The maleate salt form is used to improve the compound's solubility and stability. Detailed pharmacokinetic parameters are available from veterinary pharmacology sources.

The most common side effects of acepromazine maleate include sedation, hypotension, and hypothermia. In animals, it may cause bradycardia, respiratory depression, and, in some cases, extrapyramidal symptoms. Acepromazine maleate should be used with caution in animals with cardiovascular disease, liver disease, or seizure disorders.

Promethazine belongs to the phenothiazine class of compounds. Its structure is 10H-phenothiazine, with an acetyl group at position 2 and a 3-(dimethylamino)propyl group at position 10. It is a phenothiazine antipsychotic drug. Promethazine is a methyl ketone, aromatic ketone, tertiary amine compound belonging to the phenothiazine class. Promethazine is a phenothiazine derivative psychotropic drug, rarely used in humans, but commonly used as a sedative and antiemetic in animals. Promethazine is a phenothiazine derivative with inhibitory effects on the central nervous system. Promethazine acts as a dopamine receptor antagonist in the central nervous system, causing sedation, muscle relaxation, and reduced spontaneous activity. Its rapid onset of action and low toxicity are of particular value in veterinary medicine. A phenothiazine drug used to treat psychosis. See also: Promethazine maleate (in salt form).

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Drug Indications
Promethazine was first used in humans in the 1950s as an antipsychotic drug. It is now rarely used in humans. Promethazine is commonly used in animals as a sedative and antiemetic. Its main value lies in calming and sedating anxious animals.

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Mechanism of Action
Promethazine acts as an antagonist (blocker) on different postsynaptic receptors—dopaminergic receptors (D1, D2, D3, and D4 subtypes—with different antipsychotic properties for productive and nonproductive symptoms), serotonergic receptors (5-HT1 and 5-HT2, with anti-anxiety, antidepressant, and anti-aggressive effects, and can reduce the side effects of extrapyramidal drugs, but can also cause weight gain, hypotension, sedation, and ejaculatory dysfunction), histaminergic receptors (H1 receptors, with sedative, antiemetic, dizziness, hypotension, and weight gain effects), and α1/α2 receptors (with antisympathetic effects, can lower blood pressure, and inhibit reflexes). Tachycardia, dizziness, sedation, excessive salivation and urinary incontinence, and sexual dysfunction (but may also alleviate pseudo-Parkinsonian syndrome—this is controversial). Finally, it acts on muscarinic (cholinergic) M1/M2 receptors (causing anticholinergic symptoms such as dry mouth, blurred vision, constipation, difficulty/inability to urinate, sinus tachycardia, ECG changes, and memory loss, but the anticholinergic effect may reduce extrapyramidal side effects).

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Pharmacodynamics
Acetrazine is a phenothiazine psychotropic drug. Acetrazine acts on various levels of the central nervous system—primarily the subcortical level—and multiple organ systems. Acetrazine has potent antiadrenergic activity and weak peripheral anticholinergic activity; its ganglion blocking effect is relatively weak. It also has mild antihistamine and antiserotonin activity.
Acepromazine maleate is the maleate salt form of acepromazine, a phenothiazine derivative used primarily in veterinary medicine as a sedative and antiemetic. It acts as a dopamine receptor antagonist in the CNS, causing sedation, muscular relaxation, and reduced spontaneous activity. Acepromazine maleate is available under various brand names including Calmivet and Vetranquil. It is not commonly used in human medicine.

C23H26N2O5S

442.53

442.156

3598-37-6

Acepromazine;61-00-7

6077

Light yellow to yellow solid powder

1.155g/cm3

497ºC at 760 mmHg

135-136ºC

254.4ºC

4.22

0

4

5

23

414

0

CC(C(C=C1N2CCCN(C)C)=CC=C1SC3=C2C=CC=C3)=O.O=C(O)/C=C\C(O)=O

FQRHOOHLUYHMGG-BTJKTKAUSA-N

InChI=1S/C19H22N2OS.C4H4O4/c1-14(22)15-9-10-19-17(13-15)21(12-6-11-20(2)3)16-7-4-5-8-18(16)23-195-3(6)1-2-4(7)8/h4-5,7-10,13H,6,11-12H2,1-3H31-2H,(H,5,6)(H,7,8)/b2-1-

1-(10-(3-(dimethylamino)propyl)-10H-phenothiazin-2-yl)ethan-1-one maleate

AcepromazineAcepromazine maleate Sch 10649 Sch10649Sch-10649

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)

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

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.)