title: Pharmacokinetics of levonorgestrel 0.75 mg tablets.
abstract: This study examined plasma levonorgestrel (LNG) concentrations and pharmacokinetics following oral administration of a single LNG 0.75 mg tablet. Sixteen healthy female volunteers 19-44 years old enrolled in the study. Serial blood samples were drawn over 72 h after dosing in a fasting state. A gas chromatographic, negative ionization mass spectrometric detection analytical method was used to determine plasma LNG concentrations. The observed mean peak plasma LNG concentration was 14.1 +/- 7.9 ng/mL (range 6.7-39.0 ng/mL). The mean time of peak concentration was 1.63 +/- 0.74 h (range 1-4 h). The plasma LNG concentration versus time profiles were subjected to noncompartmental pharmacokinetic analysis for the purposes of determining half-lives, apparent oral clearances (Cl/F), apparent volumes of distribution after oral administration (V/F), and mean residence time (MRT). Half-lives calculated from the terminal decline in plasma LNG concentrations ranged from 16.2 h to 32.3 h (mean = 24.4 +/- 5.3 h). The Cl/F was 7.06 +/- 2.69 L/h, V/F was 260 +/- 129 L, and MRT was 27.8 +/- 5.2 h. LNG was well tolerated; there were no serious adverse events during the study.
authors.affiliation: Salamandra LLC, Chevy Chase, MD, USA.
authors.forename: Karin
authors.initials: K
authors.lastname: Kook
authors.forename: Henry
authors.initials: H
authors.lastname: Gabelnick
authors.forename: Gordon
authors.initials: G
authors.lastname: Duncan
mesh_terms: D000284:Administration, Oral; D000328:Adult; D019540:Area Under Curve; D003280:Contraceptives, Oral, Synthetic / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*; D003281:Contraceptives, Postcoital / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*; D005260:Female; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D016912:Levonorgestrel / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*; D012016:Reference Values
chemical_list: D003280:Contraceptives, Oral, Synthetic; D003281:Contraceptives, Postcoital; D016912:Levonorgestrel