GANIRELIX ACETATE INJECTION (FOR SUBCUTANEOUS USE ONLY)

[freemexy]

Ganirelix Acetate Injection is a synthetic decapeptide with high antagonistic activity against naturally occurring gonadotropin-releasing hormone (GnRH). Ganirelix Acetate is derived from native GnRH with substitutions of amino acids at positions 1, 2, 3, 6, 8, and 10 to form the following molecular formula of the peptide: N-acetyl-3-(2-naphthyl)-D-alanyl-4-chloro-D-phenylalanyl-3-(3-pyridyl)-D-alanyl-L-seryl-L-tyrosyl-N9,N10-diethyl-D-homoarginyl-L-leucyl-N9,N10-diethyl-L-homoarginyl-L-prolyl-D-alanylamide acetate. The molecular weight for Ganirelix Acetate is 1570.4 as an anhydrous free base. The structural formula is as follows:Ganirelix powder

Ganirelix Acetate Injection is supplied as a colorless, sterile, ready-to-use, aqueous solution intended for SUBCUTANEOUS administration only. Each sterile, prefilled syringe contains 250 mcg/0.5 mL of Ganirelix Acetate, 0.1 mg glacial acetic acid, 23.5 mg mannitol, and water for injection adjusted to pH 5.0 with acetic acid, NF and/or sodium hydroxide, NF.

CLINICAL PHARMACOLOGY
The pulsatile release of GnRH stimulates the synthesis and secretion of luteinizing hormone (LH) and follicle-stimulating hormone (FSH). The frequency of LH pulses in the mid and late follicular phase is approximately 1 pulse per hour. These pulses can be detected as transient rises in serum LH. At midcycle, a large increase in GnRH release results in an LH surge. The midcycle LH surge initiates several physiologic actions including: ovulation, resumption of meiosis in the oocyte, and luteinization. Luteinization results in a rise in serum progesterone with an accompanying decrease in estradiol levels.

Ganirelix Acetate acts by competitively blocking the GnRH receptors on the pituitary gonadotroph and subsequent transduction pathway. It induces a rapid, reversible suppression of gonadotropin secretion. The suppression of pituitary LH secretion by Ganirelix Acetate is more pronounced than that of FSH. An initial release of endogenous gonadotropins has not been detected with Ganirelix Acetate, which is consistent with an antagonist effect. Upon discontinuation of Ganirelix Acetate, pituitary LH and FSH levels are fully recovered within 48 hours.

Pharmacokinetics
The pharmacokinetic parameters of single and multiple injections of Ganirelix Acetate Injection in healthy adult females are summarized in Table I. Steady-state serum concentrations are reached after 3 days of treatment. The pharmacokinetics of Ganirelix Acetate are dose-proportional in the dose range of 125 to 500 mcg.