Tamsulosin HCl, a marketed drug, is a potent and selective α1a adrenergic receptor antagonist used for the treatment of benign prostatic hyperplasia (BPH). It exhibits a preference for the α1A receptor found in the prostate as opposed to the α1B receptor found in blood vessels. Compared to control patients, tamsulosin-treated patients had a 0.30-fold decreased risk of experiencing acute urinary retention. Tamsulosin can be suggested as a treatment for men who have had AUR catheterization, as it can lessen the chance that they will require another catheterization.

Physicochemical Properties

Molecular Formula	C20H28N2O5S.HCL
Molecular Weight	444.97
Exact Mass	444.148
Elemental Analysis	C, 55.00; H, 6.56; Cl, 8.54; N, 6.75; O, 15.42; S, 7.73
CAS #	106463-17-6
Related CAS #	Tamsulosin;106133-20-4; Tamsulosin-d5 hydrochloride; Tamsulosin-d4 hydrochloride; 2518100-55-3
PubChem CID	5362376
Appearance	White to off-white solid powder
Boiling Point	595.5ºC at 760 mmHg
Melting Point	228-230ºC
Flash Point	313.9ºC
Vapour Pressure	3.79E-14mmHg at 25°C
LogP	4.512
Hydrogen Bond Donor Count	3
Hydrogen Bond Acceptor Count	7
Rotatable Bond Count	11
Heavy Atom Count	29
Complexity	539
Defined Atom Stereocenter Count	1
SMILES	Cl[H].S(C1=C(C([H])=C([H])C(=C1[H])C([H])([H])[C@@]([H])(C([H])([H])[H])N([H])C([H])([H])C([H])([H])OC1=C([H])C([H])=C([H])C([H])=C1OC([H])([H])C([H])([H])[H])OC([H])([H])[H])(N([H])[H])(=O)=O
InChi Key	ZZIZZTHXZRDOFM-XFULWGLBSA-N
InChi Code	InChI=1S/C20H28N2O5S.ClH/c1-4-26-17-7-5-6-8-18(17)27-12-11-22-15(2)13-16-9-10-19(25-3)20(14-16)28(21,23)24;/h5-10,14-15,22H,4,11-13H2,1-3H3,(H2,21,23,24);1H/t15-;/m1./s1
Chemical Name	5-[(2R)-2-[2-(2-ethoxyphenoxy)ethylamino]propyl]-2-methoxybenzenesulfonamide;hydrochloride
Synonyms	Tamsulosina hydrochloride; Tamsulosinum hydrochloride; Tamsulosin HCl; Pradif; Flomax; Omnic
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

Targets	α1-adrenergic receptor
ln Vitro	In vitro activity: Tamsulosin is a α1 receptor antagonist that exhibits selectivity towards the α1A receptor in the prostate as opposed to the α1B receptor in blood vessels. Compared to control patients, patients on tamsulosin had a 0.30-fold decreased risk of experiencing acute urinary retention. There were no appreciable differences in any of the male questionnaire domain scores from the International Continence Society between the groups. When treating men for AUR following catheterization, tamsulosin may be suggested as it can lower the chance of re-catheterization.
ln Vivo	Tamsulosin exhibits high plasma-protein binding, largely to α1-acid glycoprotein. Eighteen to fifteen percent of an oral dose is eliminated by the kidneys as the parent compound after it is metabolized, mostly by cytochrome P450 (CYP) 3A4 and CYP2D6 to low abundance compounds. The pharmacokinetics of tamsulosin are not affected to a major extent by age, and pharmacokinetic alterations in renally impaired patients relate largely to an increased concentration of α1-acid glycoprotein. Medication adjustment is not necessary for either mild to moderate hepatic impairment or renal impairment because pharmacokinetic changes associated with hepatic impairment are only moderate. Tamsulosin was quickly absorbed after oral administration (within 30 to 90 minutes) in early studies involving rats and dogs, but its absolute bioavailability was only 7–23% in rats and 30–42% in dogs. Tamsulosin MR has a near-100 percent absolute bioavailability in humans who are fasting. In the fed state, the tmax is approximately 6 hours (range 5.2-7.0 hours), and in the fasted state, it is usually about 5 hours (reported range of mean values 2.9-5.6 hours). Animal studies involving intravenous injection of radiolabelled tamsulosin and measurement of radiolabel in various tissues after 10 minutes have shown the presence of the drug in various tissues, ranked in the following order: kidney>lung≈heart>submaxillary gland>liver ≈spleen≈aorta≈vas deferens> prostate>>cerebral cortex, the latter being close to detection limits. The blood-brain barrier might not be crossed by tamsulosin. In rats and dogs, tamsulosin is extensively metabolized in the liver, and the parent compound is excreted in the urine at rates of 1.2% and 2.8%, respectively. While rats and dogs also experience extensive hepatic metabolism, it appears that humans experience this process to a lesser extent, as 8.7–15% of an oral dose is eliminated in the urine in an unmetabolized form. Tamsulosin is eliminated from the body at varying rates depending on the species. For example, rats and dogs eliminate tamsulosin from their bodies more quickly than humans do.
Animal Protocol	Dissolved in saline; 0.1 and 1 μg/kg; s.c. injection Female Wistar rats
References	[1]. Tamsulosin: an overview. World J Urol. 2002 Apr;19(6):397-404. [2]. Tamsulosin Attenuates Abdominal Aortic Aneurysm Growth. Surgery. 2018 Nov; 164(5): 1087-1092.
Additional Infomation	Tamsulosin hydrochloride is a hydrochloride resulting from the reaction of equimolar amounts of tamulosin and hydrogen chloride. It has a role as an alpha-adrenergic antagonist and an antineoplastic agent. It contains a tamsulosin(1+). It is an enantiomer of an ent-tamsulosin hydrochloride. Tamsulosin Hydrochloride is the hydrochloride salt of tamsulosin, a sulfonamide derivative with adrenergic antagonist activity. Tamsulosin selectivity binds to and blocks the activity of alpha1 adrenoreceptors in the human prostate and bladder neck; blockade of these adrenoceptors can cause smooth muscle in the prostate and bladder neck to relax, resulting in an improvement in urinary flow rate. A sulfonamide derivative and adrenergic alpha-1 receptor antagonist that is used to relieve symptoms of urinary obstruction caused by BENIGN PROSTATIC HYPERPLASIA. See also: Tamsulosin (annotation moved to).

Solubility Data

Solubility (In Vitro)	DMSO: ~88 mg/mL (~197.8 mM) Water: ~17 mg/mL (~38.2 mM) Ethanol: ~8 mg/mL (~18 mM)
Solubility (In Vivo)	O=S(C1=CC=C(C[C@H](NCCOC2=CC=CC=C2OCC)C)C=C1)(N)=O.[H]Cl  (Please use freshly prepared in vivo formulations for optimal results.)

Preparing Stock Solutions		1 mg	5 mg	10 mg
	1 mM	2.2473 mL	11.2367 mL	22.4734 mL
	5 mM	0.4495 mL	2.2473 mL	4.4947 mL
	10 mM	0.2247 mL	1.1237 mL	2.2473 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.