Extended-Cycle Levonorgestrel/Ethinylestradiol and Low-Dose Ethinylestradiol (Seasonique(®)): A Review of Its Use as an Oral Contraceptive

Combined oral contraceptives: update recommendations of the Latin American contraceptive association

Background: In recent years, new combined oral contraceptives (COCs) have become available, representing an advance in terms of individualization and compliance by users.Objective: To provide recommendations regarding COCs: formulations, use, efficacy, benefits and safety.Method: For these recommendations, we have used the modified Delphi methodology and carried out a systematic review of studies found in the literature and reviews performed in humans, published in English and Spanish in Pubmed, Medline and advanced medicine and computer networks until the year 2021, using the combination of terms: 'oral contraceptives', 'estroprogestins' and 'combined oral contraceptives'.Results: Regarding the estrogen component, initially switching from mestranol (the pro-drug of ethinylestradiol) to ethinylestradiol (EE) and then reducing the EE dose helped reduce side effects and associated adverse events. Natural estradiol and estradiol valerate are already available and represent a valid alternative to EE. The use of more potent 19-nortestosterone-derived progestins, in order to lower the dose and then the appearance of non-androgenic progestins with different endocrine and metabolic characteristics, has made it possible to individualize the prescription of COC according to the profile of each woman.Conclusion: Advances in the provision of new COCs have improved the risk/benefit ratio by increasing benefits and reducing risks. Currently, the challenge is to tailor contraceptives to individual needs in terms of safety, efficacy, and protection of female reproductive health.

Quantitative determination of levonorgestrel in beagle dog plasma after vaginal administration of intravaginal ring by high-performance liquid chromatography-tandem mass spectrometry

A specific and sensitive high-performance liquid chromatography-tandem mass spectrometry method that could be used to determine the concentration of levonorgestrel (LNG) in beagle dog plasma was developed. Specifically, terfenadine was used as the internal standard (IS). The separation was achieved on a Kinetex-C₁₈ 110A column (3 × 30 mm i.d., 2.6 um, Phenomenex) and a gradient mobile phase consists of methanol (0.1% formic acid) and water (0.1% formic acid) was used. The flow rate was 0.8 mL/min and the injection volume was 10 μL. The detection was performed on a triple-quadruple tandem mass spectrometer by multiple reaction monitoring mode via electrospray ionization. Quantitative analysis was carried out at m/z 313.0 → 108.9 and m/z 472.6 → 436.2 for LNG and IS respectively. This method demonstrated the linearity of LNG over a concentration range of 0.5-50 ng/mL with a coefficient correlation (r) of 0.9973. The lower limit of quantification was 0.5 ng/mL. The intra- and inter-assay precisions were 2.9 and 11.2%, with an accuracy range from 94.8 to 108.4%. The stability data indicated that sample preparation and storage process had little effect on the concentration of LNG QC sample. The validated method was successfully applied to study the pharmacokinetics of LNG in beagle dog after vaginal administration of intravaginal ring.