Racecadotril (also called acetorphan) is a potent and peripherally acting enkephalinase inhibitor used as an antidiarrheal medication. It has an IC50 of 4.5 μM against enkephalinase and prevents the degradation of endogenous enkephalins. Racecadotril has an antisecretory effect; unlike other opioid medications used to treat diarrhea, it lessens the secretion of water and electrolytes into the intestine while also reducing intestinal motility.

Physicochemical Properties

Molecular Formula	C21H23NO4S
Molecular Weight	385.48
Exact Mass	385.134
Elemental Analysis	C, 65.43; H, 6.01; N, 3.63; O, 16.60; S, 8.32
CAS #	81110-73-8
Related CAS #	Racecadotril-d5; 1246815-11-1
PubChem CID	107751
Appearance	White to off-white solid powder
Density	1.2±0.1 g/cm3
Boiling Point	574.5±50.0 °C at 760 mmHg
Melting Point	89ºC
Flash Point	301.2±30.1 °C
Vapour Pressure	0.0±1.6 mmHg at 25°C
Index of Refraction	1.579
LogP	3.44
Hydrogen Bond Donor Count	1
Hydrogen Bond Acceptor Count	5
Rotatable Bond Count	11
Heavy Atom Count	27
Complexity	485
Defined Atom Stereocenter Count	0
SMILES	O=C(CNC(C(CC1C=CC=CC=1)CSC(C)=O)=O)OCC1C=CC=CC=1
InChi Key	ODUOJXZPIYUATO-UHFFFAOYSA-N
InChi Code	InChI=1S/C21H23NO4S/c1-16(23)27-15-19(12-17-8-4-2-5-9-17)21(25)22-13-20(24)26-14-18-10-6-3-7-11-18/h2-11,19H,12-15H2,1H3,(H,22,25)
Chemical Name	benzyl 2-[[2-(acetylsulfanylmethyl)-3-phenylpropanoyl]amino]acetate
Synonyms	Acetorphan; Racecadotril
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	Opioid receptor
ln Vivo	Racecadotril is quickly converted to Thiorphan in mice after intravenous injection; as a result, 30 minutes after the injection, only Thiorphan is found in the kidney and not the parent compound, Racecadotril[1]. In rats, radioactively labeled racecadotril at a single dose of 10 mg/kg is eliminated in 24 hours in 92% of cases[1]. Racecadotril is an inhibitor of neutral endopeptidase (NEP) that has been shown to have antidiarrheal properties in animals. Racecadotril (100 mg/kg) given orally exhibits effectiveness in a rat model of diarrhea brought on by castor oil[2].
Animal Protocol	6-to-7-week-old male Wistar rats 100 mg/kg A single oral treatment; 30 minutes before castor oil administration.
References	[1]. A comprehensive review of the pharmacodynamics, pharmacokinetics, and clinical effects of the neutral endopeptidase inhibitor Racecadotril. Front Pharmacol. 2012 May 30;3:93. [2]. Pharmacologic Comparison of Clinical Neutral Endopeptidase Inhibitors in a Rat Model of Acute Secretory Diarrhea. J Pharmacol Exp Ther. 2016 May;357(2):423-31.
Additional Infomation	2-[[2-[(acetylthio)methyl]-1-oxo-3-phenylpropyl]amino]acetic acid (phenylmethyl) ester is a N-acyl-amino acid. Racecadotril has been investigated for the basic science and treatment of Diarrhea, Acute Diarrhea, and Acute Gastroenteritis.

Solubility Data

Solubility (In Vitro)

DMSO: 22~77 mg/mL (57.1~199.8 mM) Water: <1 mg/mL Ethanol: ~77 mg/mL (~199.8mM)

Solubility (In Vivo)

Solubility in Formulation 1: ≥ 2.5 mg/mL (6.49 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 (6.49 mM) in 10% DMSO + 90% (20% SBE-β-CD in Saline) (add these co-solvents sequentially from left to right, and one by one), suspension solution; with ultrasonication. 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 (6.49 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	2.5942 mL	12.9708 mL	25.9417 mL
	5 mM	0.5188 mL	2.5942 mL	5.1883 mL
	10 mM	0.2594 mL	1.2971 mL	2.5942 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.