UBP301 HCl is a potent and specific kainate receptor antagonist (inhibitor) with IC50 and Kds of 164 μM and 5.94 μM respectively. UBP301 HCl is 30 times more selective for red algae chlorate receptors than AMPA receptors. UBP301 HCl is an analogue of Willardiine.

Physicochemical Properties

Molecular Formula	C15H15CLIN3O6
Molecular Weight	495.65
Exact Mass	494.969
Related CAS #	UBP301;569371-10-4
PubChem CID	168264758
Appearance	Off-white to light yellow solid powder
Hydrogen Bond Donor Count	4
Hydrogen Bond Acceptor Count	7
Rotatable Bond Count	6
Heavy Atom Count	26
Complexity	614
Defined Atom Stereocenter Count	1
SMILES	C1=CC(=CC=C1CN2C(=O)C(=CN(C2=O)C[C@@H](C(=O)O)N)I)C(=O)O.Cl
InChi Key	SDDGQKMHQXTCMN-MERQFXBCSA-N
InChi Code	InChI=1S/C15H14IN3O6.ClH/c16-10-6-18(7-11(17)14(23)24)15(25)19(12(10)20)5-8-1-3-9(4-2-8)13(21)22;/h1-4,6,11H,5,7,17H2,(H,21,22)(H,23,24);1H/t11-;/m0./s1
Chemical Name	4-[[3-[(2S)-2-amino-2-carboxyethyl]-5-iodo-2,6-dioxopyrimidin-1-yl]methyl]benzoic acid;hydrochloride
Synonyms	UBP301 (hydrochloride); UBP-301 (hydrochloride); UBP-301 HCl
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 Note: Please store this product in a sealed and protected environment (e.g. under nitrogen), avoid exposure to moisture and light.
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	UBP301 acts as a competitive antagonist at both AMPA (GluA2 subunit, Ki = 8.2 μM) and kainate (GluK1 subunit, Ki = 2.3 μM) receptors, with moderate selectivity for kainate receptors over AMPA receptors (∼3.5-fold) [1]
ln Vitro	UBP301 acts as a competitive antagonist at both AMPA (GluA2 subunit, Ki = 8.2 μM) and kainate (GluK1 subunit, Ki = 2.3 μM) receptors, with moderate selectivity for kainate receptors over AMPA receptors (∼3.5-fold) [1]
Enzyme Assay	Radioligand displacement assays were conducted using [3H]kainate on rat cortical membranes. Membranes were incubated with UBP301 (1 nM–300 μM) and 15 nM [3H]kainate in 50 mM Tris-HCl buffer (pH 7.4, 4°C) for 45 min. Bound ligand was separated via vacuum filtration through GF/B filters, washed with ice-cold buffer, and quantified by liquid scintillation spectrometry to calculate Ki values [1]
References	[1]. Structural requirements for novel willardiine derivatives acting as AMPA and kainate receptor antagonists. Br J Pharmacol. 2003;138(6):1093-1100.
Additional Infomation	UBP301 is a 5-iodowillardiine analog designed to optimize steric bulk at the N3-position for enhanced receptor subtype discrimination. Its iodine substitution increases hydrophobic interactions within the ligand-binding domain, improving kainate receptor affinity over earlier derivatives. Serves as a key pharmacological tool for dissecting AMPA/kainate receptor contributions to excitatory neurotransmission, particularly in studies of synaptic plasticity and excitotoxicity [1]

Solubility Data

Solubility (In Vitro)

DMSO :~100 mg/mL (~201.76 mM)

Solubility (In Vivo)

Solubility in Formulation 1: ≥ 2.5 mg/mL (5.04 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 (5.04 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 (5.04 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	2.0176 mL	10.0878 mL	20.1755 mL
	5 mM	0.4035 mL	2.0176 mL	4.0351 mL
	10 mM	0.2018 mL	1.0088 mL	2.0176 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.