Absorption, Distribution and Excretion
in vitro 99% using 3H=R5020 / in vivo similar to progesterone
Orally administered gestodene is rapidly and completely absorbed.
The absolute bioavailability of gestodene was determined to be 99% of the dose administered.
For gestodene, an apparent volume of distribution of 0.7 L/kg and a metabolic clearance rate from serum of about 0.8 mL/min/kg were determined.
Following ingestion of 0.1 mg gestodene together with 0.03 mg ethinylestradiol (which represents the combination with the highest gestodene content of the tri-step formulation), maximum drug serum levels of about 5.6 ng/mL are reached at 0.5 hour.
For more Absorption, Distribution and Excretion (Complete) data for GESTODENE (8 total), please visit the HSDB record page.

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Metabolism / Metabolites
The biotransformation follows the known pathways of steroid metabolism. No pharmacologically active metabolites are known.
Gestodene is metabolized primarily in the liver by CYP 3A4 and is a strong inducer of this enzyme. Although ethinylestradiol is also metabolized by CYP 3A4, gestodene does not appear to inhibit its metabolism. Known metabolites of gestodene include dihydrogestodene, 3,5-tetrahydrogestodene and hydroxygestodene.
There is limited information on the metabolism of levonorgestrel, norethindrone and structurally related contraceptive steroids. Both levonorgestrel and norethindrone undergo extensive reduction of the alpha, beta-unsaturated ketone in ring A. Levonorgestrel also undergoes hydroxylation at carbons 2 and 16. The metabolites of both compounds circulate predominantly as sulfates. In urine, levonorgestrel metabolites are found primarily in the glucuronide form, whereas norethindrone metabolites are present in approximately equal amounts as sulfates and glucuronides. Of the progestogens structurally related to norethindrone, norethindrone acetate, ethynodiol diacetate, norethindrone enanthate, and perhaps lynestrenol, undergo rapid hydrolysis and are converted to the parent compound and its metabolites. There is no convincing evidence that norethynodrel is converted to norethindrone. Of the progestogens structurally related to levonorgestrel, it appears that neither desogestrel nor gestodene are transformed to the parent compound. However, there is evidence that norgestimate can be, at least partly, converted to levonorgestrel. ...

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Biological Half-Life
16 to 18 hrs.
Gestodene serum levels decrease in two phases, characterised by half-lives of 0.1 hours and about 18 hours.
The half-life of elimination of gestodene was shown to range from 12 to 14 hr for the three doses studied (0.025, 0.075 or 0.125 mg gestodene).
Gestodene is not excreted in unchanged form but as metabolites, which are eliminated with a half-life of about 1 day.

Interactions
... In a parallel-group study, 15 healthy women using OCs and 15 healthy women without OCs (control subjects) ingested a single dose of 4 mg tizanidine. Plasma and urine concentrations of tizanidine, as well as several of its metabolites (M-3, M-4, M-5, M-9, and M-10), and pharmacodynamic variables were measured until 24 hours after dosing. As a marker of CYP1A2 activity, an oral caffeine test was performed in both groups. The mean area under the plasma concentration-time curve from time 0 to infinity [AUC0-infinity] of tizanidine was 3.9 times greater (P<.001) and the mean peak plasma tizanidine concentration (Cmax) was 3.0 times higher (P<.001) in the OC users than in the control subjects. In 1 OC user the AUC0-infinity of tizanidine exceeded the mean AUC0-infinity of the control subjects by nearly 20 times. There were no significant differences in the elimination half-life or time to peak concentration in plasma of tizanidine between the groups. Tizanidine/metabolite ratios in plasma (M-3 and M-4) and urine (M-3, M-4, M-5, M-9, and M-10) were 2 to 10 times higher in the users of OCs than in the control subjects. In the OC group the excretion of unchanged tizanidine into urine was, on average, 3.8 times greater (P=.008) than in the control subjects. The plasma caffeine/paraxanthine ratio was 2.8 times higher (P<.001) in the OC users than in the control subjects. The caffeine/paraxanthine ratio correlated significantly with the AUC0-infinity and peak concentration of tizanidine in plasma, with its excretion into urine, and with, for example, the tizanidine/M-3 and tizanidine/M-4 area under the plasma concentration-time curve ratios. Both the systolic and diastolic blood pressures were lowered by tizanidine more in the OC users (-29+/- 10 mm Hg and -21+/- 8 mm Hg, respectively) than in the control subjects (-17+/- 9 mm Hg and -13+/- 5 mm Hg, respectively) (P < .01). OCs containing ethinyl estradiol and gestodene increase, to a clinically significant extent, the plasma concentrations and effects of tizanidine, probably mainly by inhibiting its CYP1A2-mediated presystemic metabolism. Care should be exercised when tizanidine is prescribed to OC users.

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Non-Human Toxicity Values
LD50 Mouse oral 6 g/kg

[1]. Spona, J. and J. Huber, Pharmacological and endocrine profiles of gestodene. Int J Fertil, 1987. 32 Suppl: p. 6-14.

[2]. Lack of binding of gestodene to estrogen receptor in human breast cancer tissue. Eur J Cancer, 1990. 26(5): p. 608-10.

Therapeutic Uses
Contraceptives, oral, Synthetic; Progestational hormones, Synthetic
/Triadene is indicated for/ oral contraception and the recognized gynecological indications for such estrogen-progestogen combinations.

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Drug Warnings
Some epidemiological studies have suggested an association between the use of combined oral contraceptives (COCs) and an increased risk of arterial and venous thrombotic and thromboembolic diseases such as myocardial infarction, stroke, deep venous thrombosis and pulmonary embolism. These events occur rarely. Full recovery from such disorders does not always occur, and it should be realised that in a few cases they are fatal.
/Contraindications for Triadene include/: Pregnancy; severe disturbances of liver function, jaundice or persistent itching during a previous pregnancy, Dubin-Johnson syndrome, Rotor syndrome, previous or existing liver tumors; history of confirmed venous thromboembolism (VTE). Family history of idiopathic VTE. Other known risk factors for VTE; existing or previous arterial thrombotic or embolic processes, conditions which predispose to them eg disorders of the clotting processes, valvular heart disease and atrial fibrillation; Sickle-cell anemia; mammary or endometrial carcinoma, or a history of these conditions; severe diabetes mellitus with vascular changes; disorders of lipid metabolism; history of herpes gestationis; deterioration of otosclerosis during pregnancy; undiagnosed abnormal vaginal bleeding; hypersensitivity to any of the components of Triadene.
The following conditions require strict medical supervision during medication with oral contraceptives. Deterioration or first appearance of any of these conditions may indicate that use of the oral contraceptive should be discontinued: diabetes mellitus, or a tendency towards diabetes mellitus (eg unexplained glycosuria), hypertension, varicose veins, a history of phlebitis, otosclerosis, multiple sclerosis, epilepsy, porphyria, tetany, disturbed liver function, Sydenham's chorea, renal dysfunction, family history of clotting disorders, obesity, family history of breast cancer and patient history of benign breast disease, history of clinical depression, systemic lupus erythematosus, uterine fibroids and migraine, gall-stones, cardiovascular diseases, chloasma, asthma, an intolerance to contact lenses, or any disease that is prone to worsen during pregnancy.
In rare cases, headaches, gastric upsets, nausea, vomiting, breast tenderness, changes in body weight, changes in libido, depressive moods can occur.
For more Drug Warnings (Complete) data for GESTODENE (44 total), please visit the HSDB record page.

C21H26O2

310.43

310.193

60282-87-3

Gestodene-d6;1542211-40-4

3033968

White to off-white solid powder

1.2±0.1 g/cm3

462.7±45.0 °C at 760 mmHg

190-192°C

196.9±21.3 °C

0.0±2.6 mmHg at 25°C

1.588

3.65

1

2

2

23

648

6

CC[C@]12CC[C@H]3[C@H]([C@@H]1C=C[C@]2(C#C)O)CCC4=CC(=O)CC[C@H]34

PCGOZSMTJRCWQF-ZUHHCLADSA-N

InChI=1S/C21H26O2/c1-3-20-11-9-17-16-8-6-15(22)13-14(16)5-7-18(17)19(20)10-12-21(20,23)4-2/h2,5,10,12,16-19,23H,3,6-9,11,13H2,1H3/t16-,17+,18+,19-,20-,21+/m0/s1

(17α)-13-Ethyl-17-hydroxy-18,19-dinorpregna-5,15-dien-20-yn-3-one

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: ≥ 2.75 mg/mL (8.86 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 27.5 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: ≥ 2.75 mg/mL (8.86 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 27.5 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: ≥ 2.75 mg/mL (8.86 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 27.5 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.)