Formestane (CGP-32349)   中文名称: 福美斯坦

Absorption, Distribution and Excretion
Formestane has poor oral bioavailability, but is fully bioavailable when administered via the established intramuscular route. The AUC after an intravenous pulse dose does not vary considerably from that of an intramuscular dose. Within 24-48 h of the first dose of intramuscular formestane, a C(max) of 48.0 +/- 20.9 nmol/l was achieved in one study. [2]
Renal elimination. >95% in urine, <5% in feces.
Vd = 1.8 L/kg; widely distributed to organs and tissues when delivered intravenously. [2]
Plasma clearance is approximately 4.2 L/(h kg), when delivered intravenously. In women, following a 500mg dose of formestane, 20% was excreted as glucuronide within the first 24 hours. [1] One long term metabolite (3beta,4alpha-dihydroxy-5alpha-androstan-17-one) can be detected for 90 hours. A longer detection time is possible with more sensitive technology, which may be of utility in sports drug testing. [1]

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Metabolism / Metabolites
Hepatic metabolism. Phase I of metabolism is mainly reductive in nature. The reduction products 3 beta-hydroxy-5alpha-androstane-4,17-dione and 3alpha-hydroxy-5beta-androstane-4,17-dione are produced, and further reduced. A notable step in the process of metabolism is a keto reduction on carbon number three of the molecule. The main metabolite which is produced from formestane is 4-hydroyxyandrost-4-ene-3,17-dione-4-glucuronide. The oxidation products identified were 4-hydroxyandrosta-4,6-diene-3,17-dione and 4-hydroxyandrosta-1,4-diene-3,17-dione. In phase II, conjugation was diverse and included sulfatation and glucuronidation. 4-hydroxytestosterone, the 17-hydroxylated analog to formestane, was identified as one particular metabolite found in women's urine. This finding was the result of an oral administration of 500mg of formestane in women.

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Biological Half-Life
Terminal plasma elimination half life of 18 minutes, when delivered intravenously. [2]

Steroids.2013Nov;78(11):1103-9;Ann Oncol.1994;5 Suppl 7:S19-24.

Formestane is a 17-oxo steroid that is androst-4-ene-3,17-dione in which the hydrogen at position 4 is replaced by a hydroxy group. Formestane was the first selective, type I steroidal aromatase inhibitor, suppressing oestrogen production from anabolic steroids or prohormones. It was formerly used in the treatment of oestrogen-receptor positive breast cancer in post-meopausal women. As it has poor oral bioavailability, it had to be administered by (fortnightly) intramuscular injection. It fell out of use with the subsequent development of cheaper, orally active aromatase inhibitors. Formestane is listed by the World Anti-Doping Agency as a substance prohibited from use by athletes. It has a role as an EC 1.14.14.14 (aromatase) inhibitor and an antineoplastic agent. It is a 3-oxo-Delta(4) steroid, a 17-oxo steroid, a hydroxy steroid and an enol. It derives from a hydride of an androstane.
Formestane was the first selective, type I, steroidal aromatase inhibitor used in the treatment of estrogen-receptor positive breast cancer in post-menopausal women. Formestane suppresses estrogen production from anabolic steroids or prohormones. Formestane is also a prohormone of 4-hydroxytestosterone, an active steroid with weak androgenic activity and mild aromatase inhibitor activity. It is listed as a prohibited substance by the World Anti-Doping Agency for use in athletes. Formestane has poor oral bioavailability, and thus must be administered fortnightly (bi-weekly) by intramuscular injection. Some clinical data has suggested that the clinically recommended dose of 250mg was too low. With the discovery of newer, non-steroidal and steroidal, aromatase inhibitors which were orally active and less expensive than formestane, formestane lost popularity. Currently, formestane (categorized as an anti-estrogenic agent) is prohibited from use in sports in accordance to the regulations of the World Anti-Doping Agency. It is not US FDA approved, and the intramuscular injection form of formestane (Lentaron) which was approved in Europe has been withdrawn.
Formestane is a synthetic steroidal substance with antineoplastic activity. Formestane binds irreversibly to and inhibits the enzyme aromatase, thereby blocking the conversion of cholesterol to pregnenolone and the peripheral aromatization of androgenic precursors into estrogens. (NCI04)
See also: 4-Hydroxytestosterone (annotation moved to).

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Drug Indication
For the treatment of estrogen-receptor positive breast cancer in post-menopausal women.

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Mechanism of Action
Formestane is a second generation, irreversible, steroidal aromatase inhibitor. It inhibits the aromatase enzyme responsible for converting androgens to estrogens, thereby preventing estrogen production. Breast cancer may be estrogen sensitive or insensitive. A majority of breast cancers are estrogen sensitive. Estrogen sensitive breast cancer cells depend on estrogen for viability. Thus removal of estrogen from the body can be an effective treatment for hormone sensitive breast cancers. Formestane has been targeted specifically for the treatment of postmenopausal women. Unlike premenopausal women who produce most estrogen in the ovaries, postmenopausal women produce most estrogen in peripheral tissues with the help of the aromatase enzyme. Formestane, an aromatase inhibitor, can thus help to decrease the local production of estrogen by blocking the aromatase enzyme in peripheral tissues (ie. adispose tissue of the breast) to treat hormone sensitive breast cancer.

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Pharmacodynamics
By significantly reducing estrogen levels in the bloodstream, formestane may exhibit antitumor activity. In one trial involving 147 postmenopausal females with advanced breast cancers resistant to standard therapies, 22% of patients achieved a partial response, while another 20% achieved disease stabilization. [3] In comparative trials comparing a non-steroidal aromatase inhibitor, anastrozole, with formestane, it was found that anastrozole was more effective and consistent at suppressing estrogen levels in the body. However, these results were of unverified clinical significance. [5]

C19H26O3

302.41

302.188

566-48-3

11273

Typically exists as solid at room temperature

1.2±0.1 g/cm3

475.4±45.0 °C at 760 mmHg

199-202°C

255.4±25.2 °C

0.0±2.7 mmHg at 25°C

1.570

2.66

54.37

1

3

0

22

590

5

C[C@@]12CCC(=O)C(=C2CC[C@H]3[C@@H]4CCC(=O)[C@@]4(C)CC[C@@H]31)O

OSVMTWJCGUFAOD-KZQROQTASA-N

InChI=1S/C19H26O3/c1-18-10-8-15(20)17(22)14(18)4-3-11-12-5-6-16(21)19(12,2)9-7-13(11)18/h11-13,22H,3-10H2,1-2H3/t11-,12-,13-,18+,19-/m0/s1

(8R,9S,10R,13S,14S)-4-hydroxy-10,13-dimethyl-7,8,9,10,11,12,13,14,15,16-decahydro-1H-cyclopenta[a]phenanthrene-3,17(2H,6H)-dione

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)

注意: 如下所列的是一些常用的体内动物实验溶解配方，主要用于溶解难溶或不溶于水的产品（水溶度<1 mg/mL）。 建议您先取少量样品进行尝试，如该配方可行，再根据实验需求增加样品量。

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注射用配方1: DMSO : Tween 80： Saline = 10 : 5 : 85 (如： 100 μL DMSO → 50 μL Tween 80 → 850 μL Saline)
*生理盐水/Saline的制备：将0.9g氯化钠/NaCl溶解在100 mL ddH ₂ O中，得到澄清溶液。
注射用配方 2: DMSO : PEG300 ：Tween 80 : Saline = 10 : 40 : 5 : 45 (如： 100 μL DMSO → 400 μL PEG300 → 50 μL Tween 80 → 450 μL Saline)
注射用配方 3: DMSO : Corn oil = 10 : 90 (如： 100 μL DMSO → 900 μL Corn oil)
示例: 以注射用配方 3 (DMSO : Corn oil = 10 : 90) 为例说明, 如果要配制 1 mL 2.5 mg/mL的工作液, 您可以取 100 μL 25 mg/mL 澄清的 DMSO 储备液，加到 900 μL Corn oil/玉米油中, 混合均匀。

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注射用配方 4: DMSO : 20% SBE-β-CD in Saline = 10 : 90 [如：100 μL DMSO → 900 μL (20% SBE-β-CD in Saline)]
*20% SBE-β-CD in Saline的制备（4°C，储存1周）：将2g SBE-β-CD (磺丁基-β-环糊精) 溶解于10mL生理盐水中，得到澄清溶液。
注射用配方 5: 2-Hydroxypropyl-β-cyclodextrin : Saline = 50 : 50 (如： 500 μL 2-Hydroxypropyl-β-cyclodextrin (羟丙基环胡精)→ 500 μL Saline)
注射用配方 6: DMSO : PEG300 : Castor oil : Saline = 5 : 10 : 20 : 65 (如： 50 μL DMSO → 100 μL PEG300 → 200 μL Castor oil → 650 μL Saline)
注射用配方 7: Ethanol : Cremophor : Saline = 10： 10 : 80 (如： 100 μL Ethanol → 100 μL Cremophor → 800 μL Saline)
注射用配方 8: 溶解于Cremophor/Ethanol (50 : 50), 然后用生理盐水稀释。
注射用配方 9: EtOH : Corn oil = 10 : 90 (如： 100 μL EtOH → 900 μL Corn oil)
注射用配方 10: EtOH : PEG300：Tween 80 : Saline = 10 : 40 : 5 : 45 (如： 100 μL EtOH → 400 μL PEG300 → 50 μL Tween 80 → 450 μL Saline)

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口服配方 1: 悬浮于0.5% CMC Na (羧甲基纤维素钠)
口服配方 2: 悬浮于0.5% Carboxymethyl cellulose (羧甲基纤维素)
示例: 以口服配方 1 (悬浮于 0.5% CMC Na)为例说明, 如果要配制 100 mL 2.5 mg/mL 的工作液, 您可以先取0.5g CMC Na并将其溶解于100mL ddH2O中，得到0.5%CMC-Na澄清溶液；然后将250 mg待测化合物加到100 mL前述 0.5%CMC Na溶液中，得到悬浮液。

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口服配方 3: 溶解于 PEG400 (聚乙二醇400)
口服配方 4: 悬浮于0.2% Carboxymethyl cellulose (羧甲基纤维素)
口服配方 5: 溶解于0.25% Tween 80 and 0.5% Carboxymethyl cellulose (羧甲基纤维素)
口服配方 6: 做成粉末与食物混合

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注意: 以上为较为常见方法，仅供参考， InvivoChem并未独立验证这些配方的准确性。具体溶剂的选择首先应参照文献已报道溶解方法、配方或剂型，对于某些尚未有文献报道溶解方法的化合物，需通过前期实验来确定（建议先取少量样品进行尝试），包括产品的溶解情况、梯度设置、动物的耐受性等。

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请根据您的实验动物和给药方式选择适当的溶解配方/方案：
1、请先配制澄清的储备液(如：用DMSO配置50 或 100 mg/mL母液(储备液));
2、取适量母液，按从左到右的顺序依次添加助溶剂，澄清后再加入下一助溶剂。以 下列配方为例说明 (注意此配方只用于说明，并不一定代表此产品 的实际溶解配方):
10% DMSO → 40% PEG300 → 5% Tween-80 → 45% ddH2O (或 saline);
假设最终工作液的体积为 1 mL, 浓度为5 mg/mL: 取 100 μL 50 mg/mL 的澄清 DMSO 储备液加到 400 μL PEG300 中，混合均匀/澄清；向上述体系中加入50 μL Tween-80，混合均匀/澄清；然后继续加入450 μL ddH2O (或 saline)定容至 1 mL；
3、溶剂前显示的百分比是指该溶剂在最终溶液/工作液中的体积所占比例;
4、 如产品在配制过程中出现沉淀/析出，可通过加热(≤50℃)或超声的方式助溶;
5、为保证最佳实验结果，工作液请现配现用！
6、如不确定怎么将母液配置成体内动物实验的工作液，请查看说明书或联系我们;
7、 以上所有助溶剂都可在 Invivochem.cn网站购买。