WARNING: This product is for research use only, not for human or veterinary use.

MedKoo CAT#: 528827

CAS#: 96346-61-1

Description: Onapristone, also known as IVV-1001 and ZK-98299, is a progesterone receptor antagonist potentially for the treatment of breast cancer, advanced prostate cancer, and inducer of vaginal bleeding.

Chemical Structure

CAS# 96346-61-1

Theoretical Analysis

MedKoo Cat#: 528827
Name: Onapristone
CAS#: 96346-61-1
Chemical Formula: C29H39NO3
Exact Mass: 449.29
Molecular Weight: 449.630
Elemental Analysis: C, 77.47; H, 8.74; N, 3.12; O, 10.67

Price and Availability

This product is not in stock, which may be available by custom synthesis. For cost-effective reason, minimum order is 1g (price is usually high, lead time is 2~3 months, depending on the technical challenge). Quote less than 1g will not be provided. To request quote, please email to sales @medkoo.com or click below button.
Note: Price will be listed if it is available in the future.

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Synonym: IVV-1001; IVV 1001; IVV1001; ZK-98299; ZK-98299; ZK98299;

IUPAC/Chemical Name: (8S,11R,13R,14S,17S)-11-(4-(dimethylamino)phenyl)-17-hydroxy-17-(3-hydroxypropyl)-13-methyl-1,2,6,7,8,11,12,13,14,15,16,17-dodecahydro-3H-cyclopenta[a]phenanthren-3-one


InChi Code: InChI=1S/C29H39NO3/c1-28-18-25(19-5-8-21(9-6-19)30(2)3)27-23-12-10-22(32)17-20(23)7-11-24(27)26(28)13-15-29(28,33)14-4-16-31/h5-6,8-9,17,24-26,31,33H,4,7,10-16,18H2,1-3H3/t24-,25+,26-,28+,29+/m0/s1

SMILES Code: C[C@]12[C@](CCCO)(O)CC[C@@]1([H])[C@]3([H])CCC4=CC(CCC4=C3[C@@H](C5=CC=C(N(C)C)C=C5)C2)=O

Appearance: Solid powder

Purity: >98% (or refer to the Certificate of Analysis)

Shipping Condition: Shipped under ambient temperature as non-hazardous chemical. This product is stable enough for a few weeks during ordinary shipping and time spent in Customs.

Storage Condition: Dry, dark and at 0 - 4 C for short term (days to weeks) or -20 C for long term (months to years).

Solubility: Soluble in DMSO

Shelf Life: >2 years if stored properly

Drug Formulation: This drug may be formulated in DMSO

Stock Solution Storage: 0 - 4 C for short term (days to weeks), or -20 C for long term (months).

HS Tariff Code: 2934.99.9001

More Info:

Biological target:
In vitro activity:
In vivo activity:

Preparing Stock Solutions

The following data is based on the product molecular weight 449.63 Batch specific molecular weights may vary from batch to batch due to the degree of hydration, which will affect the solvent volumes required to prepare stock solutions.

Recalculate based on batch purity %
Concentration / Solvent Volume / Mass 1 mg 5 mg 10 mg
1 mM 1.15 mL 5.76 mL 11.51 mL
5 mM 0.23 mL 1.15 mL 2.3 mL
10 mM 0.12 mL 0.58 mL 1.15 mL
50 mM 0.02 mL 0.12 mL 0.23 mL
Formulation protocol:
In vitro protocol:
In vivo protocol:

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1: Rezai K, Chassard D, Denot C, Proniuk S, Zukiwski A, Gilles E, Ramos HL, Patat A, Bexon A, Lokiec F. A single-dose PK study of onapristone including the effect of food on absorption. Cancer Chemother Pharmacol. 2015 Jul;76(1):171-7. doi: 10.1007/s00280-015-2754-3. Epub 2015 May 26. PubMed PMID: 26006702.

2: Rekawiecki R, Kowalik MK, Kotwica J. Onapristone (ZK299) and mifepristone (RU486) regulate the messenger RNA and protein expression levels of the progesterone receptor isoforms A and B in the bovine endometrium. Theriogenology. 2015 Aug;84(3):348-57. doi: 10.1016/j.theriogenology.2015.03.024. Epub 2015 Apr 1. PubMed PMID: 25976976.

3: Guil-Luna S, Hellmén E, Sánchez-Céspedes R, Millán Y, Martín de las Mulas J. The antiprogestins mifepristone and onapristone reduce cell proliferation in the canine mammary carcinoma cell line CMT-U27. Histol Histopathol. 2014 Jul;29(7):949-55. doi: 10.14670/HH-29.949. Epub 2014 Feb 6. PubMed PMID: 24500783.

4: Mann GE, Wathes DC, Robinson RS. The progesterone receptor antagonist, onapristone has differential effects on the timing and control of the luteolytic mechanism depending on timing of administration in sheep. Mol Cell Endocrinol. 2013 Aug 25;376(1-2):1-11. doi: 10.1016/j.mce.2013.06.001. Epub 2013 Jun 7. PubMed PMID: 23748180.

5: Jacobs E, Watson SA, Ellis IO, Hardcastle JD, Robertson JF. The effect of onapristone, a progesterone antagonist, on the growth of human gastrointestinal cancer xenografts. Eur J Cancer. 1997 Jun;33(7):1130-5. PubMed PMID: 9376194.

6: Chwalisz K, Fahrenholz F, Hackenberg M, Garfield R, Elger W. The progesterone antagonist onapristone increases the effectiveness of oxytocin to produce delivery without changing the myometrial oxytocin receptor concentrations. Am J Obstet Gynecol. 1991 Dec;165(6 Pt 1):1760-70. PubMed PMID: 1661070.

7: Cameron ST, Glasier AF, Narvekar N, Gebbie A, Critchley HO, Baird DT. Effects of onapristone on postmenopausal endometrium. Steroids. 2003 Nov;68(10-13):1053-9. PubMed PMID: 14667998.

8: Gonçalves SC, Marques CC, Stöckemann K, Wang W, Horta AE. Influence of an antiprogestin (onapristone) on in vivo and in vitro fertilization. Anim Reprod Sci. 1997 Mar;46(1-2):55-67. PubMed PMID: 9231247.

9: Classen S, Possinger K, Pelka-Fleischer R, Wilmanns W. Effect of onapristone and medroxyprogesterone acetate on the proliferation and hormone receptor concentration of human breast cancer cells. J Steroid Biochem Mol Biol. 1993 Apr;45(4):315-9. PubMed PMID: 8499339.

10: Katkam RR, Gopalkrishnan K, Chwalisz K, Schillinger E, Puri CP. Onapristone (ZK 98.299): a potential antiprogestin for endometrial contraception. Am J Obstet Gynecol. 1995 Sep;173(3 Pt 1):779-87. PubMed PMID: 7573244.

11: Hyder SM, Chiappetta C, Stancel GM. Induction of the angiogenic factor VEGF in the uterus by the antiprogestin onapristone. Cancer Lett. 2000 Aug 1;156(1):101-7. PubMed PMID: 10840165.

12: Cameron ST, Critchley HO, Buckley CH, Chard T, Kelly RW, Baird DT. The effects of post-ovulatory administration of onapristone on the developmnent of a secretory endometrium. Hum Reprod. 1996 Jan;11(1):40-9. PubMed PMID: 8671154.

13: Chwalisz K, Hegele-Hartung C, Fritzemeier KH, Beier HM, Elger W. Inhibition of the estradiol-mediated endometrial gland formation by the antigestagen onapristone in rabbits: relationship to uterine estrogen receptors. Endocrinology. 1991 Jul;129(1):312-22. PubMed PMID: 2055191.

14: Stoeckemann K, Hegele-Hartung C, Chwalisz K. Effects of the progesterone antagonists onapristone (ZK 98 299) and ZK 136 799 on surgically induced endometriosis in intact rats. Hum Reprod. 1995 Dec;10(12):3264-71. PubMed PMID: 8822456.

15: Krusche CA, Herrler A, Classen-Linke I, Hegele-Hartung C, von Rango U, Beier HM. Modulation of endometrial transformation in gonadotrophin-stimulated and unstimulated pseudo-pregnant rabbits: studies with the progesterone receptor antagonist, onapristone. Mol Hum Reprod. 2000 Aug;6(8):726-34. PubMed PMID: 10908283.

16: Yallampalli C, Buhimschi I, Chwalisz K, Garfield RE, Dong YL. Preterm birth in rats produced by the synergistic action of a nitric oxide inhibitor (NG-nitro-L-arginine methyl ester) and an antiprogestin (onapristone). Am J Obstet Gynecol. 1996 Jul;175(1):207-12. PubMed PMID: 8694053.

17: Kraml J, Kolínská J, Kadlecová L, Zákostelecká M, Hirsová D, Schreiber V. Early and delayed effects of hydrocortisone and onapristone on intestinal brush-border enzymes and their sialylation and on thymus growth in suckling rats. J Steroid Biochem Mol Biol. 1995 Mar;52(3):251-7. PubMed PMID: 7696146.

18: Nishino T, Ishibashi K, Hirtreiter C, Nishino Y. Potentiation of the antitumor effect of tamoxifen by combination with the antiprogestin onapristone. J Steroid Biochem Mol Biol. 2009 Sep;116(3-5):187-90. doi: 10.1016/j.jsbmb.2009.05.013. Epub 2009 Jun 14. PubMed PMID: 19500671.

19: Robertson JF, Willsher PC, Winterbottom L, Blamey RW, Thorpe S. Onapristone, a progesterone receptor antagonist, as first-line therapy in primary breast cancer. Eur J Cancer. 1999 Feb;35(2):214-8. PubMed PMID: 10448262.

20: Mestre-Citrinovitz AC, Kleff V, Vallejo G, Winterhager E, Saragüeta P. A Suppressive Antagonism Evidences Progesterone and Estrogen Receptor Pathway Interaction with Concomitant Regulation of Hand2, Bmp2 and ERK during Early Decidualization. PLoS One. 2015 Apr 21;10(4):e0124756. doi: 10.1371/journal.pone.0124756. eCollection 2015 Apr 21. PubMed PMID: 25897495; PubMed Central PMCID: PMC4405574.