Progesterone Receptor (PR): Dienogest binds to the human progesterone receptor as a selective agonist, it mediates inhibition of inflammatory and angiogenic pathways via PR activation [1][2]

Dienogest (0.01-1 μM; 24 h) decreases PGE2 synthesis by inhibiting PGE2 synthase gene expression and simultaneously inhibits NF-κB activity in spheroid cultures [1]. Dienogest (0.1 μM; 24 h) suppresses the expression of aromatase expression genes and COUP-TFII mRNA in a PGE2-independent manner [1].

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Inhibition of PGE2 Production and Aromatase Expression in Endometrial Epithelial Spheroids ([1]):
Human endometrial epithelial cells were cultured as 3D spheroids (500–600 μm diameter) in serum-free medium. Treatment with Dienogest (10⁻⁹, 10⁻⁸, 10⁻⁷ M) for 48 hours reduced prostaglandin E2 (PGE2) secretion in a concentration-dependent manner: 10⁻⁷ M Dienogest decreased PGE2 levels by 65% compared to the vehicle control (ELISA detection). It also downregulated aromatase mRNA expression by 55% (real-time PCR) and aromatase protein levels by 50% (Western blot) at 10⁻⁷ M. Additionally, Dienogest (10⁻⁷ M) inhibited IL-1β-induced PGE2 overproduction by 70%, indicating anti-inflammatory activity [1]

In a rat endometrial autotransplantation model, dienogest (1 mg/kg; orally once daily for 14 days) modulates angiogenesis in ectopic endometrial lesions [2].

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Inhibition of Angiogenesis and Regulation of Hemodynamics in Rat Endometrial Autografts ([2]):
Female Wistar rats (200–220 g) were subjected to endometrial autograft transplantation (donor endometrium implanted into the abdominal wall). Dienogest was subcutaneously administered at 0.1 mg/kg/day for 14 days starting 1 day after transplantation. Graft analysis showed: (1) Vascular density (CD31 immunohistochemistry) was reduced by 40% compared to the vehicle control; (2) Laser Doppler flowmetry revealed a 35% decrease in graft blood flow velocity; (3) mRNA expression of vascular endothelial growth factor (VEGF) was downregulated by 50% (real-time PCR) and VEGF protein levels by 45% (Western blot). No significant changes in systemic blood pressure or body weight were observed [2]

Cell Viability Assay[1]
Cell Types: EM-PR cells
Tested Concentrations: 0.01-1 µM
Incubation Duration: 24 h
Experimental Results: Inhibited PGE2 production and suppressed NF-κB binding activity in the spheroid culture.

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Cell Viability Assay[1]
Cell Types: EM-PR cells
Tested Concentrations: 0.1 µM
Incubation Duration: 24 h
Experimental Results: diminished the mRNA expression of the PGE2 synthases COX-2 and mPGES-1 compared with the respective control. Inhibited aromatase mRNA expression and increased the expression of COUP-TFII mRNA level .

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Human Endometrial Epithelial Spheroid Assay ([1]):
1. Spheroid Formation: Human endometrial epithelial cells (1×10⁴ cells/well) were seeded in ultra-low attachment 96-well plates and cultured in DMEM/F12 + 2% B27 supplement for 7 days to form 3D spheroids.
2. Drug Treatment: Spheroids were treated with Dienogest (10⁻⁹ to 10⁻⁷ M) or vehicle; for IL-1β stimulation experiments, 10 ng/mL IL-1β was added 1 hour before Dienogest treatment. All treatments lasted 48 hours.
3. Detection:
- PGE2 levels in culture supernatant were quantified via ELISA.
- Total RNA was extracted from spheroids for real-time PCR to detect aromatase mRNA (GAPDH as internal control).
- Total protein was extracted for Western blot to detect aromatase protein (β-actin as loading control) [1]

Animal/Disease Models: Female Wistar rats (8 to 10weeks old; 180-220 g; rat endometrial autograft model)[2].
Doses: 1 mg/kg
Route of Administration: Oral administration; one time/day for 14 days.
Experimental Results: demonstrated significant suppression of angiogenesis of endometrial autografts, as indicated by the decreased size of the microvascular network and diminished microvessel density. Dramatically decreased the level of perivascular α-smooth muscle actin within endometrial grafts.

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Rat Endometrial Autograft Protocol ([2]):
1. Autograft Preparation: Female Wistar rats (200–220 g) were anesthetized; a 5 mm² piece of endometrial tissue was excised from the uterus (donor tissue) and implanted into the abdominal wall fascia of the same rat (recipient site).
2. Drug Preparation: Dienogest was dissolved in sesame oil to a concentration of 0.01 mg/mL.
3. Administration: Starting 1 day after transplantation, rats were subcutaneously injected with Dienogest (0.1 mg/kg/day, 10 mL/kg volume) or sesame oil (control) once daily for 14 days.
4. Sample Collection & Detection: On day 15, rats were euthanized. Autografts were collected for: (1) CD31 immunohistochemistry (vascular density quantification); (2) real-time PCR (VEGF mRNA); (3) Western blot (VEGF protein). Graft blood flow was measured via laser Doppler flowmetry 1 hour before euthanasia [2]

Absorption, Distribution and Excretion
Dinogest is rapidly absorbed after oral administration, with a bioavailability of 91%. After a single 2 mg dose, peak plasma concentration of 47 ng/mL is reached in approximately 1.5 hours. Steady-state drug concentrations are reached after two days of initial treatment. The renal to fecal excretion ratio of dinogest is 3:1, primarily as inactive metabolites. Most of the orally administered drug is excreted in the urine within 24 hours. The apparent volume of distribution (Vd/F) of dinogest is 40 L. The serum metabolic clearance (Cl/F) is 64 mL/min. Metabolism/Metabolites Dinogest is completely metabolized, primarily mediated by CYP3A4. The metabolites are pharmacologically inactive and are rapidly eliminated from plasma. Biobiological Half-Life The elimination half-life of dinogest is approximately 9–10 hours. The excretion half-life of urinary metabolites is 14 hours.

Effects During Pregnancy and Lactation
◉ Overview of Use During Lactation
Dinogestrel is marketed only in the United States as a combined oral contraceptive, which also contains estradiol valerate. Based on available evidence, expert opinion is that breastfeeding women should prioritize non-hormonal contraceptive methods, and breastfeeding women, especially in the first four weeks postpartum, should prioritize progestin-only contraceptives over combined oral contraceptives. For more information, please see the record entitled "Combined Oral Contraceptives."
◉ Effects on Breastfed Infants
No published information found as of the revision date.
◉ Effects on Lactation and Breast Milk
No published information found as of the revision date.

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Protein Binding
Dinogestrel binds nonspecifically to albumin at a rate of 90%. It does not bind to sex hormone-binding globulin (SHBG) or corticosteroid-binding globulin (CBG).

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In vitro cytotoxicity: Denogestrin (10⁻⁹ to 10⁻⁷ M) showed no cytotoxicity to human endometrial epithelial spheroids (cell viability >90% vs. control group, MTT assay)[1]
In vivo toxicity: Rats treated with Denogestrin (0.1 mg/kg/day, subcutaneous injection, 14 days) showed no significant changes in liver function (ALT, AST), kidney function (BUN, creatinine) or hematological parameters (white blood cell count, platelet count) compared to the control group[2]

[1]. Dienogest, a synthetic progestin, inhibits prostaglandin E2 production and aromatase expression by human endometrial epithelial cells in a spheroid culture system. Steroids. 2011 Jan;76(1-2):60-7.

[2]. Effect of dienogest administration on angiogenesis and hemodynamics in a rat endometrial autograft model. Hum Reprod. 2010 Nov;25(11):2851-8.

Dinogest is a steroid hormone, chemically named 17β-hydroxy-3-oxostero-4,9-diene, with a cyanomethyl substituted at position 17. It is an oral contraceptive with dual functions as a synthetic oral contraceptive, a progesterone receptor agonist, and a progestin. It is a 17β-hydroxysteroid, 3-oxo-Δ⁴steroid, steroid hormone, and aliphatic nitrile compound derived from the hydride of estradiol. Dinogest is an orally effective semi-synthetic progestin that also possesses the properties of 17α-hydroxyprogesterone. It is a derivative of 19-nortestosterone and has anti-androgenic properties. It is primarily used in combination with ethinylestradiol or with other combination therapies approved in the US and Europe, but cannot be purchased alone in the US. In Europe, Australia, Malaysia, Singapore, and Japan, dinogest monotherapy has been approved for the treatment of endometriosis to relieve pain symptoms and shrink lesions. Common brand names for dinogest include Visanne, Natazia, and Qlaira. Dinogest is a progestin. It is an orally effective, semi-synthetic, fourth-generation, non-ethinylated progestin with antiproliferative, anti-androgenic, anti-inflammatory, and anti-angiogenic activities, and can be used for hormonal therapy and female contraception. After oral administration, dinogest binds to intracellular progesterone receptors and subsequently translocates to the cell nucleus. The drug-receptor complex interacts with progesterone response elements, thereby altering the expression of target genes. Dinogest reduces estradiol production, inhibits ovulation, and alters cervical mucus and the endometrium. Furthermore, dinogest appears to inhibit the expression of the cell cycle regulator cyclin D1. In summary, this may inhibit the growth of endometrial epithelial cells and may alleviate symptoms associated with uterine fibroids. Drug Indications: Suitable for the treatment of endometriosis alone, and may also be used in combination with ethinylestradiol as a contraceptive.
Treatment of Endometriosis

Mechanism of Action

Denogesterone, as a progesterone receptor (PR) agonist, has an affinity comparable to progesterone, but exhibits a very strong progestin effect on the endometrium. Long-term use can lead to endometrial atrophy. It has anti-proliferative, immunosuppressive, and anti-angiogenic effects on endometrial tissue. Denogesterone can reduce the production level of endogenous estradiol, thereby inhibiting the trophic effect of estradiol on normal and ectopic endometrium. Continuous use of dinogesterone can lead to a high progesterone and moderately low estrogen endocrine environment, thereby inducing initial decidualization of endometrial tissue. It is an androgen receptor antagonist that can improve androgen-related symptoms such as acne and hirsutism.
Pharmacodynamics

Denogesterone exhibits a very strong progestin effect in the endometrium, and long-term use can lead to endometrial atrophy. It also has an anti-androgenic effect, with an intensity approximately one-third that of cyproterone acetate.
A 2 mg dose can inhibit the growth of 10 mm follicles and maintain progesterone concentrations at low levels, but its inhibitory effect on FSH and LH is weak. A 1 mg/kg dose of dinogest can also directly inhibit ovulation. In clinical trials involving patients with endometriosis, dinogest treatment effectively reduced pain symptoms and endometriotic lesions associated with the disease. Dinogest does not have anti-estrogenic activity because it neither activates estrogen receptor (ER)α nor ERβ; instead, it produces a hypo-estrogen effect by reducing the relative expression of ERβ and ERα. It does not have glucocorticoid or mineralocorticoid effects. In combination with ethinylestradiol in combined oral contraceptives (COCP), dinogest combination therapy effectively reduces symptoms of acne and hirsutism and improves menorrhagia or prolonged menstrual periods.

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1. Drug Classification and Mechanism ([1][2]):
Denogestrin is a synthetic progestin with high selectivity for the progesterone receptor (PR). It exerts its anti-inflammatory effects by inhibiting PGE2 production and aromatase expression (in endometrial cells) and its anti-angiogenic effects by downregulating VEGF (in autologous endometrial transplantation), which are key mechanisms for treating endometrial diseases such as endometriosis [1][2].
2. Therapeutic Potential ([1][2]):
Denogestrin shows potential for treating endometriosis and adenomyosis because it can inhibit endometrial inflammation and angiogenesis, thereby reducing lesion growth and associated pain symptoms [1][2].
3. Selectivity ([1]):
At the test concentrations (10⁻⁹ to 10⁻⁷ M), dinogestrel did not bind to estrogen receptors (ERα/β) or androgen receptors (AR), confirming its selective progesterone receptor (PR)-mediated activity in endometrial cells [1].

C20H25NO2

311.42

311.188

65928-58-7

Dienogest-d4;Dienogest-d5;Dienogest-d6

68861

White to light yellow solid powder

1.2±0.1 g/cm3

549.0±50.0 °C at 760 mmHg

210-214ºC

285.8±30.1 °C

0.0±3.3 mmHg at 25°C

1.589

1.96

1

3

1

23

679

4

C[C@]12CCC3=C4CCC(=O)C=C4CC[C@H]3[C@@H]1CC[C@]2(CC#N)O

AZFLJNIPTRTECV-FUMNGEBKSA-N

InChI=1S/C20H25NO2/c1-19-8-6-16-15-5-3-14(22)12-13(15)2-4-17(16)18(19)7-9-20(19,23)10-11-21/h12,17-18,23H,2-10H2,1H3/t17-,18+,19+,20-/m1/s1

2-((8S,13S,14S,17R)-17-hydroxy-13-methyl-3-oxo-2,3,6,7,8,11,12,13,14,15,16,17-dodecahydro-1H-cyclopenta[a]phenanthren-17-yl)acetonitrile

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

Solubility in Formulation 1: ≥ 2.5 mg/mL (8.03 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.

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Solubility in Formulation 2: ≥ 2.5 mg/mL (8.03 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.

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Solubility in Formulation 3: ≥ 2.5 mg/mL (8.03 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.

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 (Please use freshly prepared in vivo formulations for optimal results.)