(R)-(+)-Atenolol is the less active enantiomer of (R,S)-atenolol. (R,S)-atenolol is a beta-adrenergic receptor blocker (antagonist).

Physicochemical Properties

Molecular Formula	C14H22N2O3
Molecular Weight	266.34
Exact Mass	266.163
Elemental Analysis	C, 63.13; H, 8.33; N, 10.52; O, 18.02
CAS #	56715-13-0
Related CAS #	Atenolol-d7;1202864-50-3; 51706-40-2 (HCl); 29122-68-7;93379-54-5 (S isomer); 56715-13-0 (R isomer)
PubChem CID	175540
Appearance	White to off-white solid powder
Density	1.125g/cm3
Boiling Point	508ºC at 760mmHg
Melting Point	148-152ºC(lit.)
Flash Point	261.1ºC
Index of Refraction	1.54
LogP	1.543
Hydrogen Bond Donor Count	3
Hydrogen Bond Acceptor Count	4
Rotatable Bond Count	8
Heavy Atom Count	19
Complexity	263
Defined Atom Stereocenter Count	1
SMILES	CC(C)NC[C@@H](COC1=CC=C(C=C1)CC(=O)N)O
InChi Key	METKIMKYRPQLGS-LBPRGKRZSA-N
InChi Code	InChI=1S/C14H22N2O3/c1-10(2)16-8-12(17)9-19-13-5-3-11(4-6-13)7-14(15)18/h3-6,10,12,16-17H,7-9H2,1-2H3,(H2,15,18)/t12-/m0/s1
Chemical Name	2-[4-[(2S)-2-hydroxy-3-(propan-2-ylamino)propoxy]phenyl]acetamide
Synonyms	(R)-(+)-Atenolol; (R)-Atenolol; 56715-13-0; (+)-Atenolol; R(+)-Atenolol; (R)-2-(4-(2-Hydroxy-3-(isopropylamino)propoxy)phenyl)acetamide; Atenolol, (+)-; R-(+)-Atenolol;
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	Beta-1 adrenergic receptors
ln Vitro	Atenolol, a β-adrenergic receptor antagonist, is a chiral compound used for the treatment of cardiovascular diseases and to treat hypertension, coronary heart disease, arrhythmias, sinus tachycardia and myocardial infarction, where it acts preferentially upon the β-adrenergic receptors in the heart. It is marketed as a racemate, but only the (S)-enantiomer of (RS)-atenolol is responsible for the β-adrenoceptor blocking activity. Different chromatographic methods have been applied for the separation and determination of enantiomers. In this article a review is presented on liquid chromatographic methods for enantioseparation of (RS)-atenolol by both direct and indirect approaches involving practical applications of several chiral stationary phases, chiral derivatization reagents and ligand exchange and impregnation methods. These include methods using both HPLC and TLC for separation, determination and bioassay of enantiomers of atenolol. In addition, some aspects of enantioseparation under achiral phases of liquid chromatography have been briefly mentioned as applicable to (RS)-atenolol. This review provides current available enantioseparation choices not only for (RS)-atenolol but also for other applicable racemic drugs [1].
ln Vivo	In a randomized, double-blind, cross-over study in 12 healthy volunteers, the effects of single oral doses of 100 mg rac-atenolol were compared during exercise to those of equal amounts of the optically pure enantiomers, i.e., 50 mg (R)- and 50 mg (S)-atenolol. The mean rate pressure product decreased with rac-atenolol (-37%; P < 0.01) and half-dosed (S)-atenolol (-35%; P < 0.01) to the same extent, whereas (R)-atenolol caused no effect. Radioligand binding studies in beta-adrenergic receptors of the guinea pig heart yielded a eudismic ratio of 46 for (S)- to (R)-atenolol. The mean AUCs, maximal plasma concentrations, and plasma half-lives of the enantiomers were similar regardless of whether they were administered as optically pure enantiomers or as racemic mixture. On the other hand, the AUC of (R)-atenolol was 1.08-fold greater (P < 0.01) than that of the (S)-enantiomer. The reason for this finding remains unclear. We conclude that only (S)-atenolol, but not (R)-atenolol, contributes to the beta-blocking effect of currently used rac-atenolol since the same effect can be elicited with the (S)-enantiomer alone[2].
References	[1]. Bioassay, determination and separation of enantiomers of atenolol by direct and indirect approaches using liquid chromatography: A review. Biomed Chromatogr. 2018 Jan;32(1). [2]. Stereoselective features of (R)- and (S)-atenolol: clinical pharmacological, pharmacokinetic, and radioligand binding studies. Chirality. 1993;5(1):15-9.
Additional Infomation	Esatenolol is the (S)-enantiomer of atenolol. It has a role as a beta-adrenergic antagonist. Esatenolol is a beta blocker.

Solubility Data

Solubility (In Vitro)

DMSO: ≥ 100 mg/mL (375.46 mM)

Solubility (In Vivo)

Solubility in Formulation 1: ≥ 2.5 mg/mL (9.39 mM) (saturation unknown) in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution. For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 400 μL PEG300 and mix evenly; then add 50 μL Tween-80 to the above solution and mix evenly; then add 450 μL normal saline to adjust the volume to 1 mL. Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution. Solubility in Formulation 2: ≥ 2.5 mg/mL (9.39 mM) (saturation unknown) in 10% DMSO + 90% (20% SBE-β-CD in Saline) (add these co-solvents sequentially from left to right, and one by one), clear solution. For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 900 μL of 20% SBE-β-CD physiological saline solution and mix evenly. 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. Solubility in Formulation 3: ≥ 2.5 mg/mL (9.39 mM) (saturation unknown) in 10% DMSO + 90% Corn Oil (add these co-solvents sequentially from left to right, and one by one), clear solution. For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 900 μL of corn oil and mix evenly.  (Please use freshly prepared in vivo formulations for optimal results.)

Preparing Stock Solutions		1 mg	5 mg	10 mg
	1 mM	3.7546 mL	18.7730 mL	37.5460 mL
	5 mM	0.7509 mL	3.7546 mL	7.5092 mL
	10 mM	0.3755 mL	1.8773 mL	3.7546 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.