Spiradoline mesylate (U-62066 mesylate) is an arylacetamide and a selective kappa opioid receptor (κ-opioid receptor (KOR)) agonist/activator with a Ki of 8.6 nM in guinea pigs. The Kis of Spiradoline mesylate for μ and δ receptors are 252 nM and 9400 nM respectively. Spiradoline mesylate has potent diuretic, analgesic, antiarrhythmic, antitussive, neuro-protection effects and readily crosses the BBB (blood-brain barrier).

Physicochemical Properties

Molecular Formula	C23H34CL2N2O5S
Molecular Weight	521.50
Exact Mass	520.156
CAS #	87173-97-5
Related CAS #	Spiradoline;87151-85-7
PubChem CID	55651
Appearance	White to off-white solid powder
Hydrogen Bond Donor Count	1
Hydrogen Bond Acceptor Count	6
Rotatable Bond Count	4
Heavy Atom Count	33
Complexity	649
Defined Atom Stereocenter Count	3
SMILES	CN([C@H]1CC[C@@]2(CCCO2)C[C@@H]1N3CCCC3)C(=O)CC4=CC(=C(C=C4)Cl)Cl.CS(=O)(=O)O
InChi Key	FHEZDPDAYTVKKG-JLBKCEDKSA-N
InChi Code	InChI=1S/C22H30Cl2N2O2.CH4O3S/c1-25(21(27)14-16-5-6-17(23)18(24)13-16)19-7-9-22(8-4-12-28-22)15-20(19)26-10-2-3-11-26;1-5(2,3)4/h5-6,13,19-20H,2-4,7-12,14-15H2,1H3;1H3,(H,2,3,4)/t19-,20-,22-;/m0./s1
Chemical Name	2-(3,4-dichlorophenyl)-N-methyl-N-[(5R,7S,8S)-7-pyrrolidin-1-yl-1-oxaspiro[4.5]decan-8-yl]acetamide;methanesulfonic acid
HS Tariff Code	2934.99.9001
Storage	Powder-20°C 3 years 4°C 2 years In solvent -80°C 6 months -20°C 1 month Note: Please store this product in a sealed and protected environment, avoid exposure to moisture.
Shipping Condition	Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

Biological Activity

Targets	Ki: 8.6 nM (κ-opioid receptor in guinea pig), 252 nM (μ-receptor) and 9400 nM (δ-receptor)[2]
ln Vitro	Employing the patch-clamp technique on isolated rat heart myocytes, it was found that spirolline mesylate (15 to 500 μM) inhibits potassium currents and sodium channels in cardiac tissue to create its antiarrhythmmic effect. At higher dosages, it also blocks potassium channels. Consequently, spirolidine mesylate decreases the sustained plateau potassium amplitude, decreases the peak sodium current, and speeds up the transient outward potassium current's decay rate[2].
ln Vivo	In non-stressed adults, spiradoline mesylate (U-62066; 0.1-0.4 mg/kg; subcutaneous injection; once; Sprague-Dawley rats) treatment dose-dependently reduces social behaviors, resulting in social avoidance at the highest dose tested. However, younger animals show reduced sensitivity to this socially suppressing effect of spiradoline mesylate. The Spiradoline mesylate's socially suppressive effects are decreased in stressed animals at all ages, with juveniles and adolescents displaying greater social preference in response to specific dosages of U-62066[1].
Animal Protocol	Animal/Disease Models: Juvenile, adolescent and adult SD (Sprague-Dawley) male and female rats exposed to repeated restraint[1] Doses: 0.1 mg/kg, 0.2 mg/kg, 0.3 mg/kg, and 0.4 mg/kg Route of Administration: subcutaneous (sc) injection; once Experimental Results: Dose-dependently decreased social behaviors in non-stressed adults, producing social avoidance at the highest dose tested.
References	[1]. Stress alters social behavior and sensitivity to pharmacological activation of kappa opioid receptors in an age-specific manner in Sprague Dawley rats. Neurobiol Stress. 2018 Sep 11;9:124-132. [2]. M-L G Wadenberg. A review of the properties of spiradoline: a potent and selective kappa-opioid receptor agonist. CNS Drug Rev. Summer 2003;9(2):187-98.

Solubility Data

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

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 (e.g. IP/IV/IM/SC) 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). 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) 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). 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 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.  (Please use freshly prepared in vivo formulations for optimal results.)

Preparing Stock Solutions		1 mg	5 mg	10 mg
	1 mM	1.9175 mL	9.5877 mL	19.1755 mL
	5 mM	0.3835 mL	1.9175 mL	3.8351 mL
	10 mM	0.1918 mL	0.9588 mL	1.9175 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.