Absorption, Distribution and Excretion
Rapidly absorbed into the systemic circulation after intranasal administration. Bioavailability from a 400 µg dose averaged 2.8% (range 1.2 to 5.6%). Not absorbed after oral administration.

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Metabolism / Metabolites
Enzymatic hydrolysis.

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Biological Half-Life
3 hours

Protein Binding
Approximately 80%.

Ludwig C, Desmoulins PO, Driancourt MA, Goericke-Pesch S, Hoffmann B. Reversible downregulation of endocrine and germinative testicular function (hormonal castration) in the dog with the GnRH-agonist azagly-nafarelin as a removable implant 'Gonazon'; a preclinical trial. Theriogenology. 2009 Apr 15;71(7):1037-45. doi: 10.1016/j.theriogenology.2008.10.015. Epub 2009 Feb 23. PubMed PMID: 19233456.

Nafarelin Acetate can cause developmental toxicity according to state or federal government labeling requirements.
Nafarelin is a potent synthetic agonist of gonadotropin-releasing hormone with 3-(2-naphthyl)-D-alanine substitution at residue 6. Nafarelin has been used in the treatments of central precocious puberty and endometriosis.
Nafarelin is a Gonadotropin Releasing Hormone Receptor Agonist. The mechanism of action of nafarelin is as a Gonadotropin Releasing Hormone Receptor Agonist.
Nafarelin Acetate is the acetate salt form of nafarelin, a modified synthetic porcine luteinizing hormone (LH)-releasing hormone peptide analog, with gonadotropin-releasing hormone (GnRH) agonist activity. Upon nasal inhalation, nafarelin acetate binds to the GnRH receptor. This initially results in the release of the gonadotropins, follicle-stimulating hormone (FSH) and LH, from the pituitary gland; however, prolonged stimulation of the GnRH receptor desensitizes the receptor, which leads to decreased secretion of FSH and LH. In females, the inhibition of gonadotropin secretion causes hypogonadotropic hypogonadism leading to decreased production of estrogen and progesterone and anovulation. In males, the inhibition of LH secretion prevents the production and release of testosterone from Leydig cells in the testes and causes a significant decline in testosterone production that is near the levels seen following castration.
A potent synthetic agonist of GONADOTROPIN-RELEASING HORMONE with 3-(2-naphthyl)-D-alanine substitution at residue 6. Nafarelin has been used in the treatments of central PRECOCIOUS PUBERTY and ENDOMETRIOSIS.
See also: Nafarelin Acetate (has salt form).

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Drug Indication
For treatment of central precocious puberty (true precocious puberty, GnRH-dependent precocious precocity, complete isosexual precocity) in children of both sexes and for the treatment of endometriosis.
FDA Label

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Mechanism of Action
Like GnRH, initial or intermittent administration of nafarelin stimulates release of the gonadotropins luteinizing hormone (LH) and follicle-stimulating hormone (FSH) from the pituitary gland, which in turn transiently increases production of estradiol in females and testosterone in both sexes. However, with continuous daily administration, nafarelin continuously occupies the GnRH receptor, leading to a reversible down-regulation of the GnRH receptors in the pituitary gland and desensitization of the pituitary gonadotropes. This causes a significant and sustained decline in the production of LH and FSH. A decline in gonadotropin production and release causes a dramatic reversible decrease in synthesis of estradiol, progesterone, and testosterone by the ovaries or testes. Like normal endometrium, endometriotic implants contain estrogen receptors. Estrogen stimulates the growth of endometrium. Use of nafarelin induces anovulation and amenorrhea and decreases serum concentrations of estradiol to the postmenopausal range, which induces atrophy of endometriotic implants. However, nafarelin does not abolish the underlying pathophysiology of endometriosis. In children with central precocious puberty receiving nafarelin, serum LH, testosterone, and estradiol concentrations return to prepubertal levels. This results in the supression of secondary sexual characteristics and decrased rate of linear growth and skeletal maturation. Following disconinuation of nafarelin, the effects of the drug is reversed, meaning FSH and LH concentrations usually return to pretreatment levels.

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Pharmacodynamics
Nafarelin is a potent agonistic analog of gonadotropin-releasing hormone (GnRH). At the onset of administration, nafarelin stimulates the release of the pituitary gonadotropins, luteinizing hormone (LH) and follicle-stimulating hormone (FSH), resulting in a temporary increase of gonadal steroidogenesis. Repeated dosing abolishes the stimulatory effect on the pituitary gland. Twice daily administration leads to decreased secretion of gonadal steroids by about 4 weeks; consequently, tissues and functions that depend on gonadal steroids for their maintenance become quiescent. After nafarelin therapy is discontinued, pituitary and ovarian function normalize and estradiol serum concentrations increase to pretreatment levels. Recurrences of endometriosis are frequent after cessation of any hormonal therapy, or surgery that leaves the ovaries and/or uterus intact.

C66H83N17O13

1322.49

1321.635

76932-56-4

86220-42-0 (acetate);76932-56-4;

25077405

Typically exists as solid at room temperature

1.5±0.1 g/cm3

1.711

0.89

16

15

33

96

2730

9

O=C([C@]([H])(C([H])([H])C([H])([H])C([H])([H])/N=C(\N([H])[H])/N([H])[H])N([H])C([C@]([H])(C([H])([H])C([H])(C([H])([H])[H])C([H])([H])[H])N([H])C([C@@]([H])(C([H])([H])C1C([H])=C([H])C2=C([H])C([H])=C([H])C([H])=C2C=1[H])N([H])C([C@]([H])(C([H])([H])C1C([H])=C([H])C(=C([H])C=1[H])O[H])N([H])C([C@]([H])(C([H])([H])O[H])N([H])C([C@]([H])(C([H])([H])C1=C([H])N([H])C2=C([H])C([H])=C([H])C([H])=C12)N([H])C([C@]([H])(C([H])([H])C1=C([H])N=C([H])N1[H])N([H])C([C@]1([H])C([H])([H])C([H])([H])C(N1[H])=O)=O)=O)=O)=O)=O)=O)=O)N1C([H])([H])C([H])([H])C([H])([H])[C@@]1([H])C(N([H])C([H])([H])C(N([H])[H])=O)=O

(S)-1-(((R)-2-((S)-2-((S)-2-((S)-2-((S)-3-(1H-imidazol-4-yl)-2-((S)-5-oxopyrrolidine-2-carboxamido)propanamido)-3-(1H-indol-3-yl)propanamido)-3-hydroxypropanamido)-3-(4-hydroxyphenyl)propanamido)-3-(naphthalen-2-yl)propanoyl)-L-leucyl-L-arginyl)-N-(2-amino-2-oxoethyl)pyrrolidine-2-carboxamide

RWHUEXWOYVBUCI-ITQXDASVSA-N SMILES

Nafarelin

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)

May dissolve in DMSO (in most cases), if not, try other solvents such as H2O, Ethanol, or DMF with a minute amount of products to avoid loss of samples

Note: Listed below are some common formulations that may be used to formulate products with low water solubility (e.g. < 1 mg/mL), you may test these formulations using a minute amount of products to avoid loss of samples.

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Injection Formulation 1: DMSO : Tween 80： Saline = 10 : 5 : 85 (i.e. 100 μL DMSO stock solution → 50 μL Tween 80 → 850 μL Saline)
*Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH ₂ O to obtain a clear solution.
Injection Formulation 2: DMSO : PEG300 ：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL DMSO → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline)
Injection Formulation 3: DMSO : Corn oil = 10 : 90 (i.e. 100 μL DMSO → 900 μL Corn oil)
Example: Take the Injection Formulation 3 (DMSO : Corn oil = 10 : 90) as an example, if 1 mL of 2.5 mg/mL working solution is to be prepared, you can take 100 μL 25 mg/mL DMSO stock solution and add to 900 μL corn oil, mix well to obtain a clear or suspension solution (2.5 mg/mL, ready for use in animals).

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Injection Formulation 4: DMSO : 20% SBE-β-CD in saline = 10 : 90 [i.e. 100 μL DMSO → 900 μL (20% SBE-β-CD in saline)]
*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.
Injection Formulation 5: 2-Hydroxypropyl-β-cyclodextrin : Saline = 50 : 50 (i.e. 500 μL 2-Hydroxypropyl-β-cyclodextrin → 500 μL Saline)
Injection Formulation 6: DMSO : PEG300 : castor oil : Saline = 5 : 10 : 20 : 65 (i.e. 50 μL DMSO → 100 μLPEG300 → 200 μL castor oil → 650 μL Saline)
Injection Formulation 7: Ethanol : Cremophor : Saline = 10： 10 : 80 (i.e. 100 μL Ethanol → 100 μL Cremophor → 800 μL Saline)
Injection Formulation 8: Dissolve in Cremophor/Ethanol (50 : 50), then diluted by Saline
Injection Formulation 9: EtOH : Corn oil = 10 : 90 (i.e. 100 μL EtOH → 900 μL Corn oil)
Injection Formulation 10: EtOH : PEG300：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL EtOH → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline)

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Oral Formulation 1: Suspend in 0.5% CMC Na (carboxymethylcellulose sodium)
Oral Formulation 2: Suspend in 0.5% Carboxymethyl cellulose
Example: Take the Oral Formulation 1 (Suspend in 0.5% CMC Na) as an example, if 100 mL of 2.5 mg/mL working solution is to be prepared, you can first prepare 0.5% CMC Na solution by measuring 0.5 g CMC Na and dissolve it in 100 mL ddH2O to obtain a clear solution; then add 250 mg of the product to 100 mL 0.5% CMC Na solution, to make the suspension solution (2.5 mg/mL, ready for use in animals).

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Oral Formulation 3: Dissolved in PEG400
Oral Formulation 4: Suspend in 0.2% Carboxymethyl cellulose
Oral Formulation 5: Dissolve in 0.25% Tween 80 and 0.5% Carboxymethyl cellulose
Oral Formulation 6: Mixing with food powders

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Note: Please be aware that the above formulations are for reference only. InvivoChem strongly recommends customers to read literature methods/protocols carefully before determining which formulation you should use for in vivo studies, as different compounds have different solubility properties and have to be formulated differently.

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