IMPLANON™ (etonogestrel implant) is an off-white, non- biodegradable, etonogestrel-containing single sterile rod implant for subdermal use. The implant is 4 cm in length with a diameter of 2 mm (see Figure 1). Each IMPLANON™ rod consists of an ethy- lene vinylacetate (EVA) copolymer core, containing 68 mg of the synthetic progestin etonogestrel (ENG), surrounded by an EVA copolymer skin. The release rate is 60-70 µg/day in week 5-6 and decreases to approximately 35-45 µg/day at the end of the first year, to approximately 30-40 µg/day at the end of the second year, and then to approximately 25-30 µg/day at the end of the third year. IMPLANON™ is a progestin-only contraceptive and does not contain estrogen. IMPLANON™ does not contain latex and is not radio-opaque.

Figure 1 (Not to scale)

ENG [13-Ethyl-17-hydroxy-11-methylene-18,19-dinor-17α-pregn-4- en-20-yn-3-one], structurally derived from 19-nortestosterone, is the synthetic biologically active metabolite of the synthetic progestin desogestrel. It has a molecular weight of 324.46 and the following structural formula:

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