Vantas (Histrelin Acetate Implant) - Description

DESCRIPTION

Vantas™ (histrelin implant) is a sterile non-biodegradable, diffusion-controlled reservoir drug delivery system designed to deliver histrelin continuously for 12 months upon subcutaneous implantation. The Vantas implant contains 50 mg of histrelin acetate. Histrelin acetate is a synthetic nonapeptide analogue of the naturally occurring gonadotropin releasing hormone (GnRH) or luteinizing hormone releasing hormone (LH-RH). The sterile Vantas implantation device (provided with the implant) is used to insert the implant subcutaneously in the inner aspect of the upper arm. After 12 months, the implant must be removed. At the time the implant is removed, another implant may be inserted to continue therapy.

The sterile Vantas ™ implant consists of a 50-mg histrelin acetate drug core inside a non-biodegradable, 3 cm by 3.5 mm cylindrically shaped hydrogel reservoir (Figure A). The drug core also contains the inactive ingredient stearic acid NF. The hydrogel reservoir is a hydrophilic polymer cartridge composed of 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, trimethylolpropane trimethacrylate, benzoin methyl ether, Perkadox-16, and Triton X-100. The hydrated implant is packaged in a glass vial containing 2.0 mL of 1.8% NaCl solution. The implant is primed for release of the drug upon insertion.

Figure A. Vantas Histrelin Implant diagram (not to scale)

Histrelin acetate is chemically described as 5-oxo-L-prolyl-L-histidyl-L-tryptophyl-L-seryl-L-tyrosyl-N^t-benzyl-D-histidyl-L-leucyl-L-arginyl-N-ethyl-L-prolinamide acetate (salt) [C₆₆H₈₆N₁₈O₁₂. (1.7-2.8 moles) CH₃COOH, (0.6-7.0 moles) H₂O], with the molecular weight of 1443.70 (or 1323.50 as histrelin base. Histrelin acetate has the following structural formula