The plasma protein binding of norelgestromin is approximately 99% and it is bound to albumin but not to SHBG. Conversely, levonorgestrel is approximately 98% bound to plasma proteins and is bound to both albumin and SHBG.Norgestimate is extensively metabolized into its active metabolites during first-pass metabolism in the liver and intestines. The major metabolite of norgestimate is norelgestromin and is formed from norgestimate via deacetylation in the liver and intestines. A more minor metabolite of norgestimate is levonorgestrel, which accounts for 20 to 25% (22 ± 6%) of an administered dose or about 40 to 70 µg norgestimate, and a very minor metabolite of norgestimate is levonorgestrel 17β-acetate. Both of these metabolites are active similarly to norgelstromin. With a typical oral contraceptive dosage of norgestimate of 200 to 250 µg/day, an amount of 50 to 60 µg/day levonorgestrel may be produced. This is similar to the ovulation-inhibiting dosage of levonorgestrel, and suggests that norgestimate may act in considerable part as a prodrug specifically of levonorgestrel. Following their formation, the active metabolites of norgestimate are inactivated via reduction, hydroxylation, and conjugation into levonorgestrel metabolites. The terminal half-life of norelgestromin is between 17 and 37 hours and of levonorgestrel is between 24 and 32 hours. The metabolites of norgestimate are eliminated 47% in urine and 37% in feces. Unchanged norgestimate is undetectable in urine. Chemistry
Norgestimate, also known as 17α-ethynyl-18-methyl-19-nortestosterone 3-oxime 17β-acetate or as 17α-ethynyl-18-methylestr-4-en-17β-ol-3-one 3-oxime 17β-acetate, is a synthetic estrane steroid and a derivative of testosterone. It is a racemic mixture of E and Z isomers.
Reteplase, trade names include Retavase, is a thrombolytic drug, used to treat heart attacks by breaking up the clots that cause them. Reteplase is a recombinant non-glycosylated form of human tissue plasminogen activator, which has been modified to contain 357 of the 527 amino acids of the original protein. It is produced in the bacterium Escherichia coli. Reteplase was approved for use in 1996.Reteplase is similar to recombinant human tissue plasminogen activator (alteplase), but the modifications give reteplase a longer half-life of 13–16 minutes. Reteplase also binds fibrin with lower affinity than alteplase, improving its ability to penetrate into clots. As reteplase  is able to penetrate inside the thrombi, an enhanced fibrinolytic activity will be achieved → rapid reperfusion → low incidence of bleeding. == References ==