Bicisate (Free base) is a novel and potent tracer to measure cerebral blood flow

Physicochemical Properties

Molecular Formula	C12H24N2O4S2
Molecular Weight	324.46
Exact Mass	324.118
CAS #	121251-02-3
Related CAS #	14344-58-2 (HCl);
PubChem CID	72048
Appearance	Typically exists as solid at room temperature
Melting Point	196-198ºC
LogP	0.67
Hydrogen Bond Donor Count	4
Hydrogen Bond Acceptor Count	8
Rotatable Bond Count	13
Heavy Atom Count	20
Complexity	265
Defined Atom Stereocenter Count	2
SMILES	C(N[C@H](C(OCC)=O)CS)CN[C@H](C(OCC)=O)CS
InChi Key	RZQNBTMGBODDSK-UWVGGRQHSA-N
InChi Code	InChI=1S/C12H24N2O4S2/c1-3-17-11(15)9(7-19)13-5-6-14-10(8-20)12(16)18-4-2/h9-10,13-14,19-20H,3-8H2,1-2H3/t9-,10-/m0/s1
Chemical Name	ethyl (2R)-2-[2-[[(2R)-1-ethoxy-1-oxo-3-sulfanylpropan-2-yl]amino]ethylamino]-3-sulfanylpropanoate
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
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

ADME/Pharmacokinetics	Absorption, Distribution and Excretion After intravenous administration, bicisate presents a very large brain extraction. About 5% of the administered dose remains in the blood one hour after administration. The highest concentration of radioactivity in blood was attained 0.5 minutes after intravenous injection and it represented 13.9% of the injected dose. After intravenous administration of bicisate, the permeability surface area was 0.48 ml.g/min. Bicisate is primarily excreted by the kidneys. It has been reported that 50% of the dose is excreted in urine two hours after initial administration and even 74% of the administered dose is excreted in urine after 24 hours. Fecal excretion just accounts for 12.5% of the administered dose 48 hours after initial administration. After intravenous administration of bicisate, the distribution volume was 0.74 L. The clearance of bicisate from 1 to 24 hours, studied as a loss of hydrophilic tracer, is of approximate 3.5% per hour. Metabolism / Metabolites Bicisate is metabolized to form mono- and di-acids by the action of esterases. The exact metabolic transformation has not been elucidated. Biological Half-Life The stability of bicisate is superior when compared to other brain radiopharmaceuticals. Thus, the reported half-life of bicisate is of 6.02 hours. When broadly studied in clinical trials, the pharmacokinetic profile fits a three-compartment model with half-lives of 43 seconds, 49.5 minutes and 533 minutes.
Toxicity/Toxicokinetics	Protein Binding Bicisate and its major metabolites are not protein-bound.
Additional Infomation	Bicisate, also known as ethyl cysteinate dimer (ECD), is a N,N'-1,2-ethylene-di-yl-bis-L-cysteinate diethyl ester. It is used in conjunction with technetium Tc99m as a tracer to measure cerebral blood flow with single-photon emission computed tomography (SPECT). The complex of bicisate and technetium Tc99m as a kit was developed by Lantheus Medcl and FDA-approved on November 23, 1994. See also: Bicisate dihydrochloride (active moiety of). Drug Indication Bicisate as a complex with technetium Tc-99m is used in single photon emission computerized tomography (SPECT) as an adjunct to conventional CT or MRI in the localization of stroke in patients whom the presence of a stroke has already been diagnosed. It is not indicated to assess the functional viability of brain tissue or to distinguish between a stroke and other brain lesions. A stroke is defined as a condition in which the blood stops flowing to any part of the brain causing a damage to brain cells. The potential effect of a stroke depends on the part of the brain that was affected by it as well as the extension of the damage. Mechanism of Action Bicisate is rapidly uptaken by the brain. The retention of bicisate in the brain is associated with stereospecific de-esterification to hydrophilic acid derivatives. Even though both DD and LL isomers demonstrate brain uptake, only the LL presents brain retention. Bicisate brain localization is performed by passive diffusion and the presence of slow hydrolysis in the blood and rapid hydrolysis in the brain. The hydrolysis of bicisate forms the monoacid and diacid bicisate derivatives. The formation of these derivatives results in high brain uptake and retention. The uptake of bicisate depends on the blood flow directed to the brain and thus the presence of a stroke will be translated into specific zones in the brain that would not include the complex of bicisate and technetium Tc-99m. Pharmacodynamics The neutral and lipophilic nature of bicisate provides it with high stability. This property is given by its N2S2 core. This characteristic has been proven to allow bicisate to be used even several hours after preparation and to present an easy passage through the blood-brain barrier.

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	3.0820 mL	15.4102 mL	30.8204 mL
	5 mM	0.6164 mL	3.0820 mL	6.1641 mL
	10 mM	0.3082 mL	1.5410 mL	3.0820 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.