Levonorgestrel implant containing

Levonorgestrel implants consist of 6 Silastic capsules each capsule is 2.4 mm in diameter and 34 mm in length and contains 36 mg levonorgestrel. Total administered (implanted) dose is 216 mg. Perform implantation of all 6 capsules during the first 7 days of menses onset. Insertion is subdermal in the mid-portion of the upper arm (see literature included with the product). 

Capsules for subcutaneous implantation, containing levonorgestrel for contraception and levonorgestrel containing intra-uterine devices are available in some countries. They are highly effective and their efficacy lasts for several years. 

Impiant Contraceptive Systems (Progestins) levonorgestrel 6 capsules, each containing 36 mg levonorgestrel for subdermal implantation... 

IMPLANT CONTRACEPTIVE SYSTEM. Levonorgestrel, a progestin, is available as an implant contraceptive system (Norplant System). Six capsules, each containing levonorgestrel, are implanted under local anestiiesia in die subdermal (below the skin) tissues of the mid-portion of die upper arm. The capsules provide contraceptive protection for 5 years but may be removed at any time at die request of the patient. See Table 52-3 for more information on ways to promote an optimal response when taking die contraceptive hormones. 

FIGURE 18 In vivo cumulative weight loss (o) and cumulative release of levonorgestrel (o) from a crossUnked polymer prepared from a 3,9-bis(ethylidene-2,4,8,10-tetraoxaspiro[5,5]undecane)/3-methyl-1,5-pentanediol prepolymer crossUnked with 1,2,6-hexane triol. Polymer rods, 2.4 X 20 mm, containing 30 wt% levonorgestrel and 7.1 mol% Mg(OH)2. Devices implanted subcutaneously in rabbits. (From Ref. 15.)... 

The Norplant contraceptive implant is a set of six flexible, closed capsules made of a dimethylsiloxane/ methylvinylsiloxane copolymer containing levonorgestrel. The silicone rubber copolymer serves as rate-... 

Intrauterine devices (IUDs) can also contain the steroids. One style contains 38 mg of progesterone, which is released slowly over 1 year. One containing levonorgestrel is under development. Unmedicated rings appear to work just as effectively, although the details of their action are not well known. They appear to create an environment unsuitable for sperm and ovum and inhibit implantation. They can be made of polyethylene, stainless steel, or copper, with the last being the most common. 

Levonorgestrel blood plasma levels determined by radioimmunoassay showed a reasonably constant level for one year, once the initial burst subsided. However, the steady state plasma level was too low and thus a more rapidly eroding polymer was needed. To achieve a more rapid erosion, a material containing 7 wt% Mg(OH) 2 and 1 mole% copol nmerized 9,10-dihydrox) stearic acid was prepared. The detdces were again implanted into rabbits and levonorgestrel blood plasma level determined. Results of these studies have shown a much higher, satisfactory drug pltisma level (Heller, 1993). 

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