Following further metabolism of etonogestrel, which occurs mainly by reduction of the Δ4-3-keto group (by 5α- and 5β-reductases) and hydroxylation (by monooxygenases), the major metabolite of desogestrel is 3α,5α-tetrahydroetonogestrel. Desogestrel has a very short terminal half-life of about 1.5 hours while etonogestrel has a relatively long elimination half-life of about 21 to 38 hours, reflecting the nature of desogestrel as a prodrug. Desogestrel and etonogestrel are eliminated exclusively as metabolites 50% in urine and 35% in feces. Chemistry
Desogestrel, also known as 3-deketo-11-methylene-17α-ethynyl-18-methyl-19-nortestosterone or as 11-methylene-17α-ethynyl-18-methylestr-4-en-17β-ol, is a synthetic estrane steroid and a derivative of testosterone. It is more specifically a derivative of norethisterone (17α-ethynyl-19-nortestosterone) and is a member of the gonane (13β-ethylgonane or 18-methylestrane) subgroup of the 19-nortestosterone family of progestins. Desogestrel is the C3 deketo analogue of etonogestrel and the C3 deketo and C11 methylene analogue of levonorgestrel. Synthesis
A chemical synthesis of desogestrel has been published. History
Desogestrel was synthesized in 1972 by Organon International in the Netherlands and was first described in the literature in 1975. It was developed following the discovery that C11 substitutions enhance the biological activity of norethisterone. Desogestrel was introduced for medical use in 1981 under the brand names Marvelon and Desogen in the Netherlands. Along with gestodene and norgestimate, it is sometimes referred to as a "third-generation" progestin based on the time of its introduction to the market. It was the first of the three "third-generation" progestins to be introduced.
Concretion in the palpebral conjunctiva, is called conjunctival concretion, that is a (or a cluster of) small, hard, yellowish-white calcified matter, superficially buried beneath the palpebral conjunctiva. Most of concretions in the eye form in the palpebral conjunctiva, which is a clear membrane to surround the inside of the eyelid; fewer can be located in the cornea and retina. Symptoms
Conjunctival concretions are generally asymptomatic. Common symptoms include eye discomfort, eye irritation, and foreign body sensation. Sometimes, the larger, harder or multiple concretions make the rubbing off of the superficial layers of the conjunctiva or eyelids to cause conjunctival abrasion, especially prominent when blinking. In severe cases, dysfunction or inflammation of the Meibomian (Meibomianitis, an inflammation of the tarsal glands) glands may occur. Cause
Chronic conjunctivitis (e.g. trachoma) and aging factor are two causes of conjunctival concretion, which will make the conjunctiva cellular degeneration to produce an epithelial inclusion cyst, filled with epithelial cells and keratin debris. After calcification, the conjunctival cyst hardens and forms a conjunctival concretion. Congenital conjunctival concretion condition is also more common. Clinical Statistics
Conjunctival concretions can be single, also multiple, less confluent. There is no difference between the site of the occurrence on the upper and lower eyelid, nor right or left eye. The vast majority of concretions are in the conjunctival surface rather than deep. There is no difference in age for predilection or incidence of concretions, due to the causes of conjunctivitis, aging, and even congenital factor.