Abstract
Levonorgestrel (LNG) is a synthetic progestin that is available in oral contraceptive tablets, a subdermal implant, and an intrauterine system for contraception. LNG pharmacokinetics are a pivotal determinant of contraceptive efficacy and essential in assessing drug-drug interactions influencing LNG exposure following different routes of LNG administration. A highly sensitive LC-MS/MS method was developed and validated to quantify levonorgestrel in human plasma. Liquid-liquid extraction was utilized with a sample volume of 500 μL to extract levonorgestrel from plasma. Chromatographic separation of LNG was achieved with a Fortis™ C18 (3 μm: 100 mm × 2.1 mm) reverse phase analytical column. The mobile phases consisted of de-ionized water plus 0.1% NH4OH (100:0.1%, v/v) (A), and methanol plus 0.1% NH4OH (100:0.1%, v/v) (B) delivered as a gradient at a flow rate of 400 μL/min. Detection of LNG and internal standard (D-(−)-norgestrel-d7) was achieved using positive polarity mode monitoring at 313.2–245.2 amu and 320.1–251.2 amu, respectively. The assay was linear over the calibration range of 49.6 to 1500 pg/mL. This method was used to quantify plasma LNG released by subdermal implant in support of a drug interaction study among women with HIV receiving efavirenz- or nevirapine-based antiretroviral therapy.
Original language | English (US) |
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Pages (from-to) | 106-112 |
Number of pages | 7 |
Journal | Journal of Chromatography B: Analytical Technologies in the Biomedical and Life Sciences |
Volume | 1084 |
DOIs | |
State | Published - May 1 2018 |
Keywords
- LC-MS/MS
- Levonorgestrel
- Liquid-liquid extraction
- Plasma
- Subdermal implant
ASJC Scopus subject areas
- Analytical Chemistry
- Biochemistry
- Clinical Biochemistry
- Cell Biology