Abarelix for injectable suspension (Plenaxis™ ) is a synthetic decapeptide
with potent antagonistic activity against naturally occurring gonadotropin releasing-hormone
(GnRH). Plenaxis™ inhibits gonadotropin and related androgen production
by directly and competitively blocking GnRH receptors in the pituitary.
Abarelix is chemically described as acetyl-D-β-naphthylalanyl-D-4-chlorophenylalanyl-
L-prolyl-D-alanyl-amide. It is initially manufactured as an acetate water complex
and converted to a carboxymethylcellulose (CMC) water complex in manufacturing
the drug product. The molecular weight for abarelix anhydrous free base is 1416.06.
The structural formula for abarelix peptide is:
Abarelix for injectable suspension is supplied as a white to off-white sterile
dry powder which, when mixed with the diluent, 0.9% Sodium Chloride Injection,
USP, becomes a depot suspension intended for intramuscular (IM) injection. The
single-dose vial contains 113 mg of anhydrous free base abarelix peptide (net)
supplied in an abarelix CMC complex. This complex also contains 19.1 to 31 mg
of CMC. After the vial is reconstituted with 2.2 mL of 0.9% sodium chloride
injection, 2 mL is administered to deliver a dose of 100 mg of abarelix (net)
as the abarelix CMC complex at a pH of 5±1.
Last reviewed on RxList: 5/26/2011
This monograph has been modified to include the generic and brand name in many instances.