Fadrozole (CGS 16949A) is a highly potent and selective nonsteroidal aromatase inhibitor (IC50 of 6.4 nM) with potential antineoplastic activity. Aromatase, a member of the cytochrome P-450 superfamily, is found in many tissues; overexpression has been linked to the development of preneoplastic and neoplastic changes in breast tissue. Check for active clinical trials or closed clinical trials using this agent. Fadrozole specifically inhibits aromatase, blocking the aromatization of androstenedione and testosterone into estrone and estradiol, respectively, the final step in estrogen biosynthesis; the reduction in estrogen levels may inhibit growth in estrogen-dependent cancers.

Physicochemical Properties

Molecular Formula	C14H13N3
Molecular Weight	223.27312
Exact Mass	223.11
Elemental Analysis	C, 75.31; H, 5.87; N, 18.82
CAS #	102676-47-1
Related CAS #	Fadrozole hydrochloride;102676-31-3;Dexfadrostat;102676-87-9;Fadrozole hydrochloride hemihydrate;176702-70-8;;102676-47-1; 2743427-54-3 (phosphate)
PubChem CID	59693
Appearance	White to off-white solid powder
Density	1.2±0.1 g/cm3
Boiling Point	481.7±38.0 °C at 760 mmHg
Melting Point	0ºC
Flash Point	245.1±26.8 °C
Vapour Pressure	0.0±1.2 mmHg at 25°C
Index of Refraction	1.662
LogP	1.88
Hydrogen Bond Donor Count	0
Hydrogen Bond Acceptor Count	2
Rotatable Bond Count	1
Heavy Atom Count	17
Complexity	311
Defined Atom Stereocenter Count	0
InChi Key	CLPFFLWZZBQMAO-UHFFFAOYSA-N
InChi Code	InChI=1S/C14H13N3/c15-8-11-4-6-12(7-5-11)14-3-1-2-13-9-16-10-17(13)14/h4-7,9-10,14H,1-3H2
Chemical Name	4-(5,6,7,8-tetrahydroimidazo[1,5-a]pyridin-5-yl)benzonitrile
Synonyms	Fadrozole; CGS 16949A; CGS-16949A; CGS16949A; 102676-47-1; 4-(5,6,7,8-tetrahydroimidazo[1,5-a]pyridin-5-yl)benzonitrile; CGS-16949A; Fadrozole [INN]; Benzonitrile, 4-(5,6,7,8-tetrahydroimidazo[1,5-a]pyridin-5-yl)-; CHEMBL9298; FAD 286A; Fadrozole free base
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
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

Targets	Aromatase (IC50 = 6 nM)
ln Vitro	The rat ovary and human placenta both exhibit strong aromatase inhibition when exposed to fadrozole hydrochloride. With an IC50 of 0.03 μM, fadrozole salty suppresses the synthesis of estrogen in hamster ovarian slices. The IC50 value for the inhibition of progesterone production is 120 μM. To varied degrees, the manufacture of additional cytochrome P-450-dependent hormones can be inhibited by high doses of fadrozole hydrochloride. [1].
ln Vivo	In immature female rats, fadrozole administered orally suppresses the uterine hypertrophy generated by androstenedione-mediated aromatase, with an ED50 of 0.03 mg/kg. Aminoglutethimide administered orally in the same mouse produced the same result, with an ED50 of 30 mg/kg [1]. In female Sprague-Dawley rats, fadrozole hydrochloride inhibits the growth of spontaneous mammary tumors, both malignant and benign. Additionally, it can lessen the frequency of spontaneous hepatic tumors in both male and female rats as well as slow down the spontaneous development of pituitary dtamas in female rats [2]. Fadrozole was given to male and female mice, and it reduced the parasite burden by 70% while inhibiting the generation of 17b-estradiol. In male mice, this defense was linked to the recovery of particular cellular immunological responses. Interleukin-6 (IL-6) production in the spleenocytes and serum levels rose by 80%, while the expression of interleukin-6 (IL-6) in the testes of male infected mice increased tenfold. Fadrozole therapy brings these levels back to initial levels [3].
Enzyme Assay	For in vitro tests, culture grade Fadrozole was dissolved in cRPMI to the desired stock concentration, and sterilised by passage through a 0.2-mm Millipore filter. Experimental design was as follows: using a 24-well culture plate, six wells were used as untreated controls, six wells were supplemented with the vehicle in which Fadrozole was diluted, six wells were treated with different concentrations of Fadrozole. Concentrations of Fadrozole were randomised across the plates. Fadrozole was prepared to a final volume of 100 μl and added to 2 ml of medium in each well. Control cysts were treated with the solvent in which Fadrozole was diluted such that a constant volume of solvent (100 μl) was added to each well. Reproduction was measured as the number of buds that each cyst produced in response to treatment and were counted directly under a light inverted microscope. Morbidity of cysts was recognised by progressive internal disorganisation, development of lucent areas in the cytoplasm, and progressive loss of motility. Dead cysts had an opaque appearance with lucent areas in the tegmental cytoplasm and characteristic swelling. Viability was based upon granularity, bodily contortions, and methylene blue uptake. Unstained cysts were considered dead when they lacked motility and/or were characteristically granular. All viability observations were determined microscopically, and cysts were considered dead based on complete loss of motility of the anterior and posterior regions, and internal loss of movement for food intake. These observations were done under an inverted microscope using 10× and 100× magnification.[3]
Animal Protocol	Fadrozole was administered in the form of sub-dermal long-term release pellets (20 mg/wt kg, in three-week-release pellets), starting 1 week prior to the infection, using a 10-gauge needle Trochar. Three pellets were administrated during the study. Placebo pellets were administered to another group of infected mice, in the same fashion as the inhibitor. After 1 week, mice were infected as described above and killed 8 weeks later.[3] Rats are treated with daily dosing with fadrozole hydrochloride (CGS 16949A) in purified water by gavage for 2 years. There are 60 rats in each of four groups given 0, 0.05, 0.25 or 1.25 mg/kg daily. Control rats receive only water. Clinical signs are recorded weekly and the animals are examine for palpable masses every 4 weeks for the first 9 months, then every 2 weeks for the remainder of the study[2]. Mice: Fadrozole is administered in the form of sub-dermal long-term release pellets (20 mg/wt kg, in three-week-release pellets), starting 1 week prior to the infection, using a 10-gauge needle. Three pellets are administrated during the study. Placebo pellets are administered to another group of infected mice, in the same fashion as the inhibitor. After 1 week, mice are infected and killed 8 weeks later[3].
References	[1]. Fadrozole hydrochloride: a potent, selective, nonsteroidal inhibitor of aromatase for the treatment of estrogen-dependent disease. J Med Chem. 1991 Feb;34(2):725-36. [2]. Prevention of spontaneous tumours in female rats by fadrozole hydrochloride, an aromatase inhibitor. Br J Cancer. 1995 Jul;72(1):72-5. [3]. Inhibition of p-450 aromatase prevents feminisation and induces protection during cysticercosis. Int J Parasitol. 2002 Oct;32(11):1379-87.
Additional Infomation	4-(5,6,7,8-tetrahydroimidazo[1,5-a]pyridin-5-yl)benzonitrile is an imidazopyridine. Fadrozole is a nonsteroidal aromatase inhibitor fadrozole with potential antineoplastic activity. Fadrozole specifically inhibits aromatase, blocking the aromatization of androstenedione and testosterone into estrone and estradiol, respectively, the final step in estrogen biosynthesis; the reduction in estrogen levels may inhibit growth in estrogen-dependent cancers. Aromatase, a member of the cytochrome P-450 superfamily, is found in many tissues; overexpression has been linked to the development of preneoplastic and neoplastic changes in breast tissue. A selective aromatase inhibitor effective in the treatment of estrogen-dependent disease including breast cancer.

Solubility Data

Solubility (In Vitro)

DMSO : ≥ 100 mg/mL (~447.89 mM)

Solubility (In Vivo)

Solubility in Formulation 1: ≥ 2.17 mg/mL (9.72 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 21.7 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. Solubility in Formulation 2: ≥ 2.17 mg/mL (9.72 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 21.7 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. Solubility in Formulation 3: ≥ 2.17 mg/mL (9.72 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 21.7 mg/mL clear DMSO stock solution to 900 μL of corn oil and mix evenly.  (Please use freshly prepared in vivo formulations for optimal results.)

Preparing Stock Solutions		1 mg	5 mg	10 mg
	1 mM	4.4789 mL	22.3944 mL	44.7888 mL
	5 mM	0.8958 mL	4.4789 mL	8.9578 mL
	10 mM	0.4479 mL	2.2394 mL	4.4789 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.