In TGM123 mice, but not in TLM mice, spirapril (injectable; 10 mg/kg; 3 weeks) decreases alcohol consumption [2]. In treated mice, meningeal ACE activity was reduced by 40.2% by piropril [2]. Spiropril has the ability to penetrate the blood-brain barrier and prevent transgenic effects in tests [2]. In spontaneously hypertensive rats, spiropril can inhibit left ventricular hypertrophy, lessen myocardial damage, and stimulate angiogenesis [3].

Absorption, Distribution and Excretion
Bioavailability is 50% following oral administration.

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Metabolism / Metabolites
Hepatic. Converted to spiraprilat following oral administration.

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Biological Half-Life
30 to 35 hours

[1]. Noble S, Sorkin EM. Spirapril. A preliminary review of its pharmacology and therapeutic efficacy in the treatment of hypertension. Drugs. 1995 May;49(5):750-66.

[2]. Alcohol consumption is controlled by angiotensin II. FASEB J. 2001 Jul;15(9):1640-2.

[3]. Spirapril prevents left ventricular hypertrophy, decreases myocardial damage and promotes angiogenesis in spontaneously hypertensive rats. J Cardiovasc Pharmacol. 1993 Mar;21(3):362-70.

Spirapril is a dipeptide, a dithioketal, an azaspiro compound, a dicarboxylic acid monoester, an ethyl ester, a tertiary carboxamide, a secondary amino compound and a pyrrolidinecarboxylic acid. It has a role as a prodrug, an EC 3.4.15.1 (peptidyl-dipeptidase A) inhibitor and an antihypertensive agent. It is functionally related to a spiraprilat.
Spirapril is an ACE inhibitor antihypertensive drug used to treat hypertension. Spirapril is converted to the active spiraprilat after administration. ACE inhibitors are used primarily in treatment of hypertension and congestive heart failure.
Spirapril is a prodrug and non-sulfhydryl angiotensin converting enzyme (ACE) inhibitor with antihypertensive activity. Spirapril is converted in the body to its active metabolite spiraprilat. Spiraprilat competitively binds to and inhibits ACE, thereby blocking the conversion of angiotensin I to angiotensin II. This prevents the potent vasoconstrictive actions of angiotensin II and results in vasodilation. Spiraprilat also decreases angiotensin II-induced aldosterone secretion by the adrenal cortex, which leads to an increase in sodium excretion and subsequently increases water outflow.

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Drug Indication
Spirapril is an ACE inhibitor class drug used to treat hypertension.

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Mechanism of Action
Spiraprilat, the active metabolite of spirapril, competes with angiotensin I for binding at the angiotensin-converting enzyme, blocking the conversion of angiotensin I to angiotensin II. Inhibition of ACE results in decreased plasma angiotensin II. As angiotensin II is a vasoconstrictor and a negative-feedback mediator for renin activity, lower concentrations result in a decrease in blood pressure and stimulation of baroreceptor reflex mechanisms, which leads to decreased vasopressor activity and to decreased aldosterone secretion. Spiraprilat may also act on kininase II, an enzyme identical to ACE that degrades the vasodilator bradykinin.

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Pharmacodynamics
Spirapril is an angiotensin-converting enzyme (ACE) inhibitor. ACE is a peptidyl dipeptidase that catalyzes the conversion of angiotensin I to the vasoconstrictor substance, angiotensin II. By blocking ACE, spirapril decreases angiotensin II which is a vasoconstrictor and inducer of aldosterone. So by inhibiting the enzymes, aldosterone secreation is decreased (so less sodium is reabsorbed) and there is a decrease in vasoconstriction. Combined, this leades to a decrease in blood pressure.

C22H30N2O5S2

466.61

466.16

83647-97-6

Spirapril hydrochloride;94841-17-5

5311447

Typically exists as solid at room temperature

1.32 g/cm3

697.8ºC at 760 mmHg

375.8ºC

1.621

2.719

2

8

10

31

650

3

O=C([C@H](C1)N(C([C@@H](N[C@@H](CCC2=CC=CC=C2)C(OCC)=O)C)=O)CC31SCCS3)O

HRWCVUIFMSZDJS-SZMVWBNQSA-N

InChI=1S/C22H30N2O5S2/c1-3-29-21(28)17(10-9-16-7-5-4-6-8-16)23-15(2)19(25)24-14-22(30-11-12-31-22)13-18(24)20(26)27/h4-8,15,17-18,23H,3,9-14H2,1-2H3,(H,26,27)/t15-,17-,18-/m0/s1

(8S)-7-[(2S)-2-[[(2S)-1-ethoxy-1-oxo-4-phenylbutan-2-yl]amino]propanoyl]-1,4-dithia-7-azaspiro[4.4]nonane-8-carboxylic acid

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.)