RLX-33 is a potent, selective and BBB (blood-brain barrier) permeable/penetrable relaxin family peptide 3 (RXFP3) antagonist that also blocks relaxin 3 (relaxin 3)-induced ERK1/2 phosphorylation. , and the IC50 of phosphorylation of ERK1 and ERK2 were 2.36 μM, 7.82 μM and 13.86 μM, respectively. RLX-33 blocks the RXFP3 selective agonist R3/I5-induced increase in food intake in rats. RLX-33 may be utilized in the research/study of metabolic syndrome.

Physicochemical Properties

Molecular Formula	C24H19CLN4O4
Molecular Weight	462.88506436348
Exact Mass	462.109
CAS #	2784577-71-3
PubChem CID	164886639
Appearance	White to light yellow solid powder
LogP	3
Hydrogen Bond Donor Count	1
Hydrogen Bond Acceptor Count	6
Rotatable Bond Count	6
Heavy Atom Count	33
Complexity	696
Defined Atom Stereocenter Count	0
SMILES	N1(CC2=CC=CO2)C(=O)CC(C(NC2=CC=C(C3ON=C(C4=CC=C(Cl)C=C4)N=3)C=C2)=O)C1
InChi Key	LTOAWFRZXVPHAJ-UHFFFAOYSA-N
InChi Code	InChI=1S/C24H19ClN4O4/c25-18-7-3-15(4-8-18)22-27-24(33-28-22)16-5-9-19(10-6-16)26-23(31)17-12-21(30)29(13-17)14-20-2-1-11-32-20/h1-11,17H,12-14H2,(H,26,31)
Chemical Name	N-[4-[3-(4-chlorophenyl)-1,2,4-oxadiazol-5-yl]phenyl]-1-(furan-2-ylmethyl)-5-oxopyrrolidine-3-carboxamide
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

ln Vivo	RLX-33 (10 mg/kg; IP, single dose) attenuates the increase in food intake elicited by the RXFP3 selective agonist R3/I5 in male Wistar rats [1]. RLX-33 (10 mg/kg; IP, single dose) displays strong brain penetration and high protein binding in rat plasma [1]. Pharmacokinetic characteristics of RLX-33 in male Wistar rats (IP, 10 mg/kg) [1]. Brain plasma Cmax (ng/mL) 1401 1552 tmax (h) 0.5 2.0 t1/2 (h) 1.9 4.9 AUCinf (ng/mL·h) 5352 12519 CL_F (mL/min/kg) 43.8
Animal Protocol	Animal/Disease Models: Male Wistar rat (Intracerebroventricular injection of R3/I5 stimulates food intake [1] Doses: 10 mg/kg Route of Administration: IP, single dose Experimental Results: attenuates R3/I5-induced increase in food intake Animal/Disease Models: Male Wistar rat [1] Doses: 10 mg/kg Doses: IP, single dose (pharmacokinetic/PK/PK analysis) Experimental Results: It demonstrated good brain penetration and high protein binding, and the protein binding rate in rat plasma was 99.8%.
References	[1]. https://pubmed.ncbi.nlm.nih.gov/35594150/.

Solubility Data

Solubility (In Vitro)

DMSO : ~125 mg/mL (~270.04 mM)

Solubility (In Vivo)

Solubility in Formulation 1: ≥ 2.08 mg/mL (4.49 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 20.8 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	2.1603 mL	10.8017 mL	21.6034 mL
	5 mM	0.4321 mL	2.1603 mL	4.3207 mL
	10 mM	0.2160 mL	1.0802 mL	2.1603 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.