The NORPLANT SYSTEM kit contains levonorgestrel implants, a set of six flexible closed capsules made of silicone rubber tubing (Silastic® , dimethylsiloxane/methylvinylsiloxane copolymer), each containing 36 mg of the progestin levonorgestrel contained in an insertion kit to facilitate implantation. The capsules are sealed with Silastic (polydimethylsiloxane) adhesive and sterilized. Each capsule is 2.4 mm in diameter and 34 mm in length. The capsules are inserted in a superficial plane beneath the skin of the upper arm.

Information contained herewith regarding safety and efficacy was derived from studies which used two slightly different Silastic tubing formulations. The formulation being used in the NORPLANT SYSTEM has slightly higher release rates of levonorgestrel and at least comparable efficacy.

Evidence indicates that the dose of levonorgestrel provided by the NORPLANT (levonorgestrel implants unavailable in us) SYSTEM is initially about 85 mcg/day followed by a decline to about 50 mcg/day by 9 months and to about 35 mcg/day by 18 months with a further decline thereafter to about 30 mcg/day. The NORPLANT (levonorgestrel implants unavailable in us) SYSTEM is a progestin-only product and does not contain estrogen.

Levonorgestrel, (18,19-Dinorpregn-4-en-20-yn-3-one, 13-ethyl-17-hydroxy-, (17?)-(–)-), the active ingredient in the NORPLANT (levonorgestrel implants unavailable in us) SYSTEM, has a molecular weight of 312.45 and the following structural formula:

NORPLANT® (levonorgestrel implants) Structural Formula Illustration


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