ZK168281, a 25-carboxylic ester derivative of 1α,25(OH)2D3, is a novel, potent and pure VDR antagonist with a Kd value of 0.1 nM. ZK168281 is an effective inhibitor of the coactivator (CoA) interaction of its receptor. 

Physicochemical Properties

Molecular Formula	C₃₂H₄₆O₅
Molecular Weight	510.70
Exact Mass	510.335
CAS #	186371-96-0
PubChem CID	9806383
Appearance	White to off-white solid powder
Density	1.151g/cm3
Boiling Point	652.937ºC at 760 mmHg
Flash Point	204.377ºC
Vapour Pressure	0mmHg at 25°C
Index of Refraction	1.578
LogP	5.58
Hydrogen Bond Donor Count	3
Hydrogen Bond Acceptor Count	5
Rotatable Bond Count	9
Heavy Atom Count	37
Complexity	983
Defined Atom Stereocenter Count	7
SMILES	CCOC(=O)/C=C/C1(CC1)[C@@H](/C=C/[C@@H](C)[C@H]2CC[C@@H]\3[C@@]2(CCC/C3=C\C=C/4\C[C@H](C[C@@H](C4=C)O)O)C)O
InChi Key	FUDAEUIGIJZUAY-UMIRZPQISA-N
InChi Code	InChI=1S/C32H46O5/c1-5-37-30(36)14-16-32(17-18-32)29(35)13-8-21(2)26-11-12-27-23(7-6-15-31(26,27)4)9-10-24-19-25(33)20-28(34)22(24)3/h8-10,13-14,16,21,25-29,33-35H,3,5-7,11-12,15,17-20H2,1-2,4H3/b13-8+,16-14+,23-9+,24-10-/t21-,25-,26-,27+,28+,29-,31-/m1/s1
Chemical Name	ethyl (E)-3-[1-[(E,1R,4R)-4-[(1R,3aS,4E,7aR)-4-[(2Z)-2-[(3S,5R)-3,5-dihydroxy-2-methylidenecyclohexylidene]ethylidene]-7a-methyl-2,3,3a,5,6,7-hexahydro-1H-inden-1-yl]-1-hydroxypent-2-enyl]cyclopropyl]prop-2-enoate
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: (1). This product requires protection from light (avoid light exposure) during transportation and storage.(2). Please store this product in a sealed and protected environment (e.g. under nitrogen), avoid exposure to moisture.
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 Vitro	ZK168281, by virtue of its capacity to attract co-repressor (CoR) proteins, is a more potent constitutive androstenone (CAR) inverse agonist of androstanol. This connection takes place mostly through a salt bridge in helix 4 of the nuclear receptor (NR) between the conserved lysine and the CoR, but direct contact with CoR residues also stabilizes helix 12. Helix 12's fixing in the rigorously antagonistic/narrowly resistive conformation inhibits the C-terminus's energetically unfavorable free gravitation [1].
References	[1]. Antagonist- and inverse agonist-driven interactions of the vitamin D receptor and the constitutive androstane receptor with corepressor protein. Mol Endocrinol. 2005 Sep;19(9):2258-72.
Additional Infomation	ZK 168281 is a vitamin D.

Solubility Data

Solubility (In Vitro)

DMSO : ~100 mg/mL (~195.81 mM)

Solubility (In Vivo)

Note: Listed below are some common formulations that may be used to formulate products with low water solubility (e.g. < 1 mg/mL), you may test these formulations using a minute amount of products to avoid loss of samples. Injection Formulations (e.g. IP/IV/IM/SC) Injection Formulation 1: DMSO : Tween 80： Saline = 10 : 5 : 85 (i.e. 100 μL DMSO stock solution → 50 μL Tween 80 → 850 μL Saline) *Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH ₂ O to obtain a clear solution. Injection Formulation 2: DMSO : PEG300 ：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL DMSO → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline) Injection Formulation 3: DMSO : Corn oil = 10 : 90 (i.e. 100 μL DMSO → 900 μL Corn oil) Example: Take the Injection Formulation 3 (DMSO : Corn oil = 10 : 90) as an example, if 1 mL of 2.5 mg/mL working solution is to be prepared, you can take 100 μL 25 mg/mL DMSO stock solution and add to 900 μL corn oil, mix well to obtain a clear or suspension solution (2.5 mg/mL, ready for use in animals). Injection Formulation 4: DMSO : 20% SBE-β-CD in saline = 10 : 90 [i.e. 100 μL DMSO → 900 μL (20% SBE-β-CD in saline)] *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. Injection Formulation 5: 2-Hydroxypropyl-β-cyclodextrin : Saline = 50 : 50 (i.e. 500 μL 2-Hydroxypropyl-β-cyclodextrin → 500 μL Saline) Injection Formulation 6: DMSO : PEG300 : castor oil : Saline = 5 : 10 : 20 : 65 (i.e. 50 μL DMSO → 100 μLPEG300 → 200 μL castor oil → 650 μL Saline) Injection Formulation 7: Ethanol : Cremophor : Saline = 10： 10 : 80 (i.e. 100 μL Ethanol → 100 μL Cremophor → 800 μL Saline) Injection Formulation 8: Dissolve in Cremophor/Ethanol (50 : 50), then diluted by Saline Injection Formulation 9: EtOH : Corn oil = 10 : 90 (i.e. 100 μL EtOH → 900 μL Corn oil) Injection Formulation 10: EtOH : PEG300：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL EtOH → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline) Oral Formulations Oral Formulation 1: Suspend in 0.5% CMC Na (carboxymethylcellulose sodium) Oral Formulation 2: Suspend in 0.5% Carboxymethyl cellulose Example: Take the Oral Formulation 1 (Suspend in 0.5% CMC Na) as an example, if 100 mL of 2.5 mg/mL working solution is to be prepared, you can first prepare 0.5% CMC Na solution by measuring 0.5 g CMC Na and dissolve it in 100 mL ddH2O to obtain a clear solution; then add 250 mg of the product to 100 mL 0.5% CMC Na solution, to make the suspension solution (2.5 mg/mL, ready for use in animals). Oral Formulation 3: Dissolved in PEG400 Oral Formulation 4: Suspend in 0.2% Carboxymethyl cellulose Oral Formulation 5: Dissolve in 0.25% Tween 80 and 0.5% Carboxymethyl cellulose Oral Formulation 6: Mixing with food powders Note: Please be aware that the above formulations are for reference only. InvivoChem strongly recommends customers to read literature methods/protocols carefully before determining which formulation you should use for in vivo studies, as different compounds have different solubility properties and have to be formulated differently.  (Please use freshly prepared in vivo formulations for optimal results.)

Preparing Stock Solutions		1 mg	5 mg	10 mg
	1 mM	1.9581 mL	9.7905 mL	19.5810 mL
	5 mM	0.3916 mL	1.9581 mL	3.9162 mL
	10 mM	0.1958 mL	0.9790 mL	1.9581 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.