Search results for "Levonorgestrel"

Voltammetric behavior and assay of the contraceptive drug levonorgestrel in bulk, tablets, and human serum at a mercury electrode.

2004

The cyclic voltammograms of levonorgestrel (LNG) in Britton-Robinson buffers of pH 2-11 at the hanging mercury drop electrode showed a single two-electron irreversible cathodic peak over the whole pH range. This peak may be attributed to the reduction of the 3-keto-delta-4-group in the A-ring of the LNG molecule. The interfacial adsorptive character of levonorgestrel onto the surface of the hanging mercury drop electrode was identified by means of both cyclic voltammetry and chronocoulometry techniques. A simple, sensitive, and selective square-wave adsorptive cathodic stripping voltammetric procedure was developed for the quantitation of levonorgestrel. Under the optimized operational cond…

Binding of oral contraceptive progestogens to serum proteins and cytoplasmic receptor

1990

Abstract Some progestogens widely used in oral contraceptives are characterized at the level of high-affinity receptor binding as well as binding to sex hormone-binding globulin and corticosteroid-binding globulin. With regard to binding to sex hormone-binding globulin, gestodene, levonorgestrel, and to a lesser extent 3-ketodesogestrel (which is only formed from the prodrug desogestrel in the body), show a behavior that is manifested in the relatively high affinity to sex hormone-binding globulin, whereas desogestrel and norgestimate do not display any measurable affinity for this specific steroid-binding serum protein. Furthermore, levonorgestrel and gestodene dissociate very much more sl…

Global endometrial gene expression with continuous exposure to levonorgestrel (LNG) via an intrauterine system (IUS)

2014

Protrhombotic Effects of Contraceptives

2010

The use of oral contraceptives first became widespread some 40 years ago, and reports of an excess risk of cardiovascular disease among women who used these agents soon followed. Few drugs have been the object of such intensive epidemiological research, the outcome of which has provided clinicians with detailed information about risks not only of specific thrombotic diseases but also important non-contraceptive benefits from the pill. Recently, oral contraceptives have been classified by some according to "generation" (first, second, third, and most recently, fourth generation): first-generation formulations containing lynestrenol or norethindrone, second-generation formulations containing …

Does levonorgestrel emergency contraceptive have a post-fertilization effect? A review of its mechanism of action.

2016

Background: Recent studies have identified that levonorgestrel administered orally in emergency contraception (LNG-EC) is only efficacious when taken before ovulation. However, the drug does not consistently prevent follicular rupture or impair sperm function. Objective: The present systematic review is performed to analyze and more precisely define the extent to which pre-fertilization mechanisms of action may explain the drug's efficacy in pregnancy avoidance. We also examine the available evidence to determine if pre-ovulatory drug administration may be associated with post-fertilization effects. Conclusion: The mechanism of action of LNG-EC is reviewed. The drug has no ability to alter…