Effects of the selective AMPA modulator NBI-1065845 on the pharmacokinetics of midazolam or ethinyl estradiol-levonorgestrel in healthy adults

This parallel-arm, phase I study investigated the potential cytochrome P450 (CYP)3A induction effect of NBI-1065845 (TAK-653), an investigational α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor potentiator in phase II development for major depressive disorder. The midazolam treatment arm received the sensitive CYP3A substrate midazolam on Day 1, followed by NBI-1065845 alone on Days 5-13; on Day 14, NBI-1065845 was administered with midazolam, then NBI-1065845 alone on Day 15. The oral contraceptive treatment arm received ethinyl estradiol-levonorgestrel on Day 1, then NBI-1065845 alone on Days 5-13; on Day 14, NBI-1065845 was administered with ethinyl estradiol-levonorgestrel, then NBI-1065845 alone on Days 15-17. Blood samples were collected for pharmacokinetic analyses. The midazolam treatment arm comprised 14 men and 4 women, of whom 16 completed the study. Sixteen of the 17 healthy women completed the oral contraceptive treatment arm. After multiple daily doses of NBI-1065845, the geometric mean ratios (GMRs) (90% confidence interval) for maximum observed concentration were: midazolam, 0.94 (0.79-1.13); ethinyl estradiol, 1.00 (0.87-1.15); and levonorgestrel, 0.99 (0.87-1.13). For area under the plasma concentration-time curve (AUC) from time 0 to infinity, the GMRs were as follows: midazolam, 0.88 (0.78-0.98); and ethinyl estradiol, 1.01 (0.88-1.15). For levonorgestrel, the GMR for AUC from time 0 to the last quantifiable concentration was 0.87 (0.78-0.96). These findings indicate that NBI-1065845 is not a CYP3A inducer and support its administration with CYP3A substrates. NBI-1065845 was generally well tolerated, with no new safety signals observed after coadministration of midazolam, ethinyl estradiol, or levonorgestrel.

Midostaurin drug interaction profile: a comprehensive assessment of CYP3A, CYP2B6, and CYP2C8 drug substrates, and oral contraceptives in healthy participants

PURPOSE

Midostaurin, approved for treating FLT-3-mutated acute myeloid leukemia and advanced systemic mastocytosis, is metabolized by cytochrome P450 (CYP) 3A4 to two major metabolites, and may inhibit and/or induce CYP3A, CYP2B6, and CYP2C8. Two studies investigated the impact of midostaurin on CYP substrate drugs and oral contraceptives in healthy participants.

METHODS

Using sentinel dosing for participants' safety, the effects of midostaurin at steady state following 25-day (Study 1) or 24-day (Study 2) dosing with 50 mg twice daily were evaluated on CYP substrates, midazolam (CYP3A4), bupropion (CYP2B6), and pioglitazone (CYP2C8) in Study 1; and monophasic oral contraceptives (containing ethinylestradiol [EES] and levonorgestrel [LVG]) in Study 2.

RESULTS

In Study 1, midostaurin resulted in a 10% increase in midazolam peak plasma concentrations (Cmax), and 3-4% decrease in total exposures (AUC). Bupropion showed a 55% decrease in Cmax and 48-49% decrease in AUCs. Pioglitazone showed a 10% decrease in Cmax and 6% decrease in AUC. In Study 2, midostaurin resulted in a 26% increase in Cmax and 7-10% increase in AUC of EES; and a 19% increase in Cmax and 29-42% increase in AUC of LVG. Midostaurin 50 mg twice daily for 28 days ensured that steady-state concentrations of midostaurin and the active metabolites were achieved by the time of CYP substrate drugs or oral contraceptive dosing. No safety concerns were reported.

CONCLUSION

Midostaurin neither inhibits nor induces CYP3A4 and CYP2C8, and weakly induces CYP2B6. Midostaurin at steady state has no clinically relevant PK interaction on hormonal contraceptives. All treatments were well tolerated.

Assessment of the Effects of Abrocitinib on the Pharmacokinetics of Probe Substrates of Cytochrome P450 1A2, 2B6 and 2C19 Enzymes and Hormonal Oral Contraceptives in Healthy Individuals

BACKGROUND AND OBJECTIVE

Abrocitinib is an oral small-molecule Janus kinase (JAK)-1 inhibitor approved for the treatment of moderate-to-severe atopic dermatitis. In vitro studies indicated that abrocitinib is a weak time-dependent inhibitor of cytochrome P450 (CYP) 2C19/3A and a weak inducer of CYP1A2/2B6/2C19/3A. To assess the potential effect of abrocitinib on concomitant medications, drug-drug interaction (DDI) studies were conducted for abrocitinib with sensitive probe substrates of these CYP enzymes. The impact of abrocitinib on hormonal oral contraceptives (ethinyl estradiol and levonorgestrel), as substrates of CYP3A and important concomitant medications for female patients, was also evaluated.

METHODS

Three Phase 1 DDI studies were performed to assess the impact of abrocitinib 200 mg once daily (QD) on the probe substrates of: (1) 1A2 (caffeine), 2B6 (efavirenz) and 2C19 (omeprazole) in a cocktail study; (2) 3A (midazolam); and (3) 3A (oral contraceptives).

RESULTS

After multiple doses of abrocitinib 200 mg QD, there is a lack of effect on the pharmacokinetics of midazolam, efavirenz and contraceptives. Abrocitinib increased the area under the concentration time curve from 0 to infinity (AUCinf) and the maximum concentration (Cmax) of omeprazole by approximately 189 and 134%, respectively. Abrocitinib increased the AUCinf of caffeine by 40% with lack of effect on Cmax.

CONCLUSIONS

Based on the study results, abrocitinib is a moderate inhibitor of CYP2C19. Caution should be exercised when using abrocitinib concomitantly with narrow therapeutic index medicines that are primarily metabolized by CYP2C19 enzyme. Abrocitinib is a mild inhibitor of CYP1A2; however, the impact is not clinically relevant, and no general dose adjustment is recommended for CYP1A2 substrates. Abrocitinib does not inhibit CYP3A or induce CYP1A2/2B6/2C19/3A and does not affect the pharmacokinetics of contraceptives.

CLINICAL TRIALS REGISTRATION

ClinicalTrials.gov registration IDs: NCT03647670, NCT05067439, NCT03662516.

Models and methods to characterise levonorgestrel release from intradermally administered contraceptives

Microneedle (MN)-based technologies have been proposed as a means to facilitate minimally invasive sustained delivery of long-acting hormonal contraceptives into the skin. Intradermal administration is a new route of delivery for these contraceptives and therefore no established laboratory methods or experimental models are available to predict dermal drug release and pharmacokinetics from candidate MN formulations. This study evaluates an in vitro release (IVR) medium and a medium supplemented with ex vivo human skin homogenate (SH) as potential laboratory models to investigate the dermal release characteristics of one such hormonal contraceptive that is being tested for MN delivery, levonorgestrel (LNG), and provides details of an accompanying novel two-step liquid–liquid drug extraction procedure and sensitive reversed-phase HPLC–UV assay. The extraction efficiency of LNG was 91.7 ± 3.06% from IVR medium and 84.6 ± 1.6% from the medium supplemented with SH. The HPLC–UV methodology had a limit of quantification of 0.005 µg/mL and linearity between 0.005 and 25 µg/mL. Extraction and detection methods for LNG were exemplified in both models using the well-characterised, commercially available sustained-release implant (Jadelle®). Sustained LNG release from the implant was detected in both media over 28 days. This study reports for the first time the use of biologically relevant release models and a rapid, reliable and sensitive methodology to determine release characteristics of LNG from intradermally administered long-acting drug delivery systems.

Altered pharmacokinetics of combined oral contraceptives in obesity - multistudy assessment

OBJECTIVE

The objective was to evaluate the pharmacokinetics (PKs) of levonorgestrel (LNG)-containing combined oral contraceptives (COCs) in obese women.

STUDY DESIGN

We pooled and reanalyzed data from 89 women with different body mass index (BMI) categories from four clinical studies. The LNG and ethinyl estradiol (EE) PKs were analyzed utilizing a zero-order absorption (K0), two-compartment PK model to evaluate key PK parameters in relation to a range of weights, BMI and body surface area (BSA).

RESULTS

Increasing of body habitus metrics is correlated with decreasing Cmax (p<.0001) and AUCτ (p<.05) for both LNG and EE, but no correlation was found for Cmin (p≥.17). Increasing weight and BMI were associated with a modest increase (p≤.056) of clearance (CL) and appreciable increases of central volume (V1, p<.05), distribution clearance (CLd, p≤.001) and peripheral volume (V2, p<.0001) for LNG. For EE, increases in CL (p≤.009) were found with greater weight, BMI and BSA. Values of V1, CLd and V2 also increased (p<.0001) in obese subjects. The half-life and steady-state volume were greater among obese women (p<.0001) for both LNG and EE. LNG and EE PK parameters correlated well (p≤.006 for all), indicating that individual subject physiology affected both drugs similarly.

CONCLUSIONS

The primary effects of obesity on LNG and EE were a modest increase in CL and a marked increase in distribution parameters. We observed no obesity-related differences in trough LNG and EE concentrations.

IMPLICATIONS

This population PK analysis demonstrated reduced systemic exposure to LNG/EE oral contraceptives in obese subjects (Cmax and AUCτ); these particular differences are unlikely to lower contraceptive effectiveness among obese women who are correctly using LNG-containing contraceptives.

Randomized, placebo controlled phase I trial of safety, pharmacokinetics, pharmacodynamics and acceptability of tenofovir and tenofovir plus levonorgestrel vaginal rings in women

To prevent the global health burdens of human immunodeficiency virus [HIV] and unintended/mistimed pregnancies, we developed an intravaginal ring [IVR] that delivers tenofovir [TFV] at ~10mg/day alone or with levonorgestrel [LNG] at ~20μg/day for 90 days. We present safety, pharmacokinetics, pharmacodynamics, acceptability and drug release data in healthy women. CONRAD A13-128 was a randomized, placebo controlled phase I study. We screened 86 women; 51 were randomized to TFV, TFV/LNG or placebo IVR [2:2:1] and 50 completed all visits, using the IVR for approximately 15 days. We assessed safety by adverse events, colposcopy, vaginal microbiota, epithelial integrity, mucosal histology and immune cell numbers and phenotype, cervicovaginal [CV] cytokines and antimicrobial proteins and changes in systemic laboratory measurements, and LNG and TFV pharmacokinetics in multiple compartments. TFV pharmacodynamic activity was measured by evaluating CV fluid [CVF] and tissue for antiviral activity using in vitro models. LNG pharmacodynamic assessments were timed based on peak urinary luteinizing hormone levels. All IVRs were safe with no significant colposcopic, mucosal, immune and microbiota changes and were acceptable. Among TFV containing IVR users, median and mean CV aspirate TFV concentrations remained above 100,000 ng/mL 4 hours post IVR insertion and mean TFV-diphosphate [DP] concentrations in vaginal tissue remained above 1,000 fmol/mg even 3 days post IVR removal. CVF of women using TFV-containing IVRs completely inhibited [94-100%] HIV infection in vitro. TFV/LNG IVR users had mean serum LNG concentrations exceeding 300 pg/mL within 1 hour, remaining high throughout IVR use. All LNG IVR users had a cervical mucus Insler score <10 and the majority [95%] were anovulatory or had abnormal cervical mucus sperm penetration. Estimated in vivo TFV and LNG release rates were within expected ranges. All IVRs were safe with the active ones delivering sustained high concentrations of TFV locally. LNG caused changes in cervical mucus, sperm penetration, and ovulation compatible with contraceptive efficacy. The TFV and TFV/LNG rings are ready for expanded 90 day clinical testing. Trial registration ClinicalTrials.gov #NCT02235662.

Development, validation and utilization of a highly sensitive LC-MS/MS method for quantification of levonorgestrel released from a subdermal implant in human plasma

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.

The Effect of Gene Variants on Levonorgestrel Pharmacokinetics When Combined With Antiretroviral Therapy Containing Efavirenz or Nevirapine

Reduced levonorgestrel concentrations from the levonorgestrel contraceptive implant was previously seen when given concomitantly with efavirenz. We sought to assess whether single nucleotide polymorphisms (SNPs) in genes involved in efavirenz and nevirapine metabolism were linked to these changes in levonorgestrel concentration. SNPs in CYP2B6, CYP2A6, NR1I2, and NR1I3 were analyzed. Associations of participant demographics and genotype with levonorgestrel pharmacokinetics were evaluated in HIV-positive women using the levonorgestrel implant plus efavirenz- or nevirapine-based antiretroviral therapy (ART), in comparison to ART-naïve women using multivariate linear regression. Efavirenz group: CYP2B6 516G>T was associated with lower levonorgestrel log₁₀ C_max and log₁₀ AUC. CYP2B6 15582C>T was associated with lower log₁₀ AUC. Nevirapine group: CYP2B6 516G>T was associated with higher log₁₀ C_max and lower log₁₀ C_min . Pharmacogenetic variations influenced subdermal levonorgestrel pharmacokinetics in HIV-positive women, indicating that the magnitude of the interaction with non-nucleoside reverse transcriptase inhibitors (NNRTIs) is influenced by host genetics.

Clarification of contraceptive drug pharmacokinetics in obesity

Related to concerns about the role of obesity in the efficacy of contraceptive drugs, a review of the literature was carried out in regard to the pharmacokinetics of ethinyl estradiol and various progestins given by various routes of administration. Most studies show that obese women exhibit modestly lower plasma concentrations of these drugs (circa 30%) when given the same doses as normal-weight women. While the mechanism is uncertain, precedence in the literature suggests that this is due to body weight-related differences in metabolism rates. Confusing in some of the literature is that a few studies have reported erroneously calculated pharmacokinetic parameters after multiple dosing of oral contraceptives. A demonstration of appropriate pharmacokinetic methodology is provided.

Matrix and reservoir-type multipurpose vaginal rings for controlled release of dapivirine and levonorgestrel

A matrix-type silicone elastomer vaginal ring providing 28-day continuous release of dapivirine (DPV) - a lead candidate human immunodeficiency virus type 1 (HIV-1) microbicide compound - has recently demonstrated moderate levels of protection in two Phase III clinical studies. Here, next-generation matrix and reservoir-type silicone elastomer vaginal rings are reported for the first time offering simultaneous and continuous in vitro release of DPV and the contraceptive progestin levonorgestrel (LNG) over a period of between 60 and 180days. For matrix-type vaginal rings comprising initial drug loadings of 100, 150 or 200mg DPV and 0, 16 or 32mg LNG, Day 1 daily DPV release values were between 4132 and 6113μg while Day 60 values ranged from 284 to 454μg. Daily LNG release ranged from 129 to 684μg on Day 1 and 2-91μg on Day 60. Core-type rings comprising one or two drug-loaded cores provided extended duration of in vitro release out to 180days, and maintained daily drug release rates within much narrower windows (either 75-131μg/day or 37-66μg/day for DPV, and either 96-150μg/day or 37-57μg/day for LNG, depending on core ring configuration and ignoring initial lag release effect for LNG) compared with matrix-type rings. The data support the continued development of these devices as multi-purpose prevention technologies (MPTs) for HIV prevention and long-acting contraception.

Engineering a segmented dual-reservoir polyurethane intravaginal ring for simultaneous prevention of HIV transmission and unwanted pregnancy

The HIV/AIDS pandemic and its impact on women prompt the investigation of prevention strategies to interrupt sexual transmission of HIV. Long-acting drug delivery systems that simultaneously protect womenfrom sexual transmission of HIV and unwanted pregnancy could be important tools in combating the pandemic. We describe the design, in silico, in vitro and in vivo evaluation of a dual-reservoir intravaginal ring that delivers the HIV-1 reverse transcriptase inhibitor tenofovir and the contraceptive levonorgestrel for 90 days. Two polyether urethanes with two different hard segment volume fractions were used to make coaxial extruded reservoir segments with a 100 µm thick rate controlling membrane and a diameter of 5.5 mm that contain 1.3 wt% levonorgestrel. A new mechanistic diffusion model accurately described the levonorgestrel burst release in early time points and pseudo-steady state behavior at later time points. As previously described, tenofovir was formulated as a glycerol paste and filled into a hydrophilic polyurethane, hollow tube reservoir that was melt-sealed by induction welding. These tenofovir-eluting segments and 2 cm long coaxially extruded levonorgestrel eluting segments were joined by induction welding to form rings that released an average of 7.5 mg tenofovir and 21 µg levonorgestrel per day in vitro for 90 days. Levonorgestrel segments placed intravaginally in rabbits resulted in sustained, dose-dependent levels of levonorgestrel in plasma and cervical tissue for 90 days. Polyurethane caps placed between segments successfully prevented diffusion of levonorgestrel into the tenofovir-releasing segment during storage.Hydrated rings endured between 152 N and 354 N tensile load before failure during uniaxial extension testing. In summary, this system represents a significant advance in vaginal drug delivery technology, and is the first in a new class of long-acting multipurpose prevention drug delivery systems.

Effect of ticagrelor on the pharmacokinetics of ethinyl oestradiol and levonorgestrel in healthy volunteers

BACKGROUND

Cytochrome P450 3 A is involved in ticagrelor and ethinyl oestradiol/levonorgestrel metabolism; so a potential drug-drug interaction may occur.

OBJECTIVES

To assess: ticagrelor effects on ethinyl oestradiol/levonorgestrel pharmacokinetics, endogenous sex hormone levels; ethinyl oestradiol/levonorgestrel effects on ticagrelor pharmacokinetics; tolerability of ticagrelor + ethinyl oestradiol/levonorgestrel.

METHODS

This trial was a randomized, double-blind, two-way crossover, single-center study. Twenty-two healthy female volunteers (on stable ethinyl oestradiol/levonorgestrel) received 90 mg ticagrelor or placebo twice daily with ethinyl oestradiol/levonorgestrel (0.03 mg/0.15 mg; Nordette) on cycle days 1-21. Volunteers crossed over treatment on day 1/cycle 2. Pharmacokinetic parameters were evaluated on cycle day 21, and endogenous hormones assayed on cycle days 1, 7, 14 and 21.

CLINICAL TRIAL REGISTRATION NUMBER

NCT006895906.

RESULTS

Ethinyl oestradiol absorption was rapid (median t(max) approximately 1 hour), and was not affected by ticagrelor. Ticagrelor co-administration (90% confidence interval [CI]) increased AUC(0-τ), C(min), and C(max) of ethinyl oestradiol by 20% (1.03-1.40), 20% (0.96-1.50) and 31% (1.18-1.44), respectively. Ticagrelor had no effect on levonorgestrel pharmacokinetic parameters versus placebo (90% CI: AUC(0-τ) 0.97-1.10; C(min) 0.94-1.10; C(max) 1.02-1.16). Steady-state ticagrelor, and AR-C124910XX (major and equally pharmacologically active metabolite), AUC(0-τ), C(max), and t(max) were comparable with published findings. Pre-dose ticagrelor and AR-C124910XX plasma concentrations were higher on cycle day 21 versus days 7 and 14. Endogenous sex hormone plasma levels were unaffected by ticagrelor. Co-administration of ticagrelor with ethinyl oestradiol/levonorgestrel was well tolerated. Study limitations included: no ticagrelor-only arm; only one type of oral contraceptive; short study duration; using oestradiol/levonorgestrel pharmacokinetic parameters as surrogate marker for contraceptive efficacy.

CONCLUSIONS

Ticagrelor co-administration with ethinyl oestradiol/levonorgestrel increased ethinyl oestradiol exposure by approximately 20%, with no effect on levonorgestrel pharmacokinetics. No clinically relevant effect on contraceptive efficacy is expected with ethinyl oestradiol/levonorgestrel and ticagrelor co-administration.

Pharmacokinetics of a combined oral contraceptive in obese and normal-weight women

BACKGROUND

This study was conducted to compare oral contraceptive (OC) pharmacokinetics (PK) in normal-weight [body mass index (BMI) 19.0-24.9] and obese (BMI 30.0-39.9) women.

STUDY DESIGN

During the third week of the third cycle of OC use, we admitted 15 normal-weight and 15 obese women for collection of 12 venous specimens over 24 h. Using radioimmunoassay techniques, we measured levels of ethinyl estradiol (EE) and levonorgestrel (LNG). During the same cycle, women underwent twice-weekly sonography to assess ovarian follicular development and blood draws to measure endogenous estradiol (E2) and progesterone levels.

RESULTS

Obese women had a lower area under the curve (AUC; 1077.2 vs. 1413.7 pg*h/mL) and lower maximum values (85.7 vs. 129.5 pg/mL) for EE than normal-weight women (p=.04 and <0.01, respectively); EE trough levels were similar between BMI groups. The similar, but smaller, differences in their LNG levels for AUC and maximum values (C(max)) were not statistically significant. While peak values differed somewhat, the LNG trough levels were similar for obese and normal-weight women (2.6 and 2.5 ng/mL, respectively). Women with greater EE AUC had smaller follicular diameters (p=.05) and lower E2 levels (p=.04). While follicular diameters tended to be larger among obese women, these differences were not statistically significant.

CONCLUSION

OC hormone peak levels are lower among obese women compared to normal-weight women, but their trough levels are similar. In this small study, the observed PK differences did not translate into more ovarian follicular activity among obese OC users.

Pharmacokinetics of ethinylestradiol and levonorgestrel after administration of two oral contraceptive preparations

Serum concentration profiles and pharmacokinetic parameters (cmax, tmax, AUC24, AUC0-00, MRT) of ethinylestradiol (EE2) and levonorgestrel (LNG) were obtained following administration of two combined oral contraceptives. The constituents of the preparations were as follows: Gravistat (0.05 mg EE2, 0.125 mg LNG); Minisiston (0.03 mg EE2, 0.125 mg LNG). In 20 of the volunteers blood samples were taken before and up to 36 hours following the intake of a single table. In 11 women the investigation was carried out at day 21 of a treatment cycle (steady-state condition). In spite of pronounced interindividual variations of the pharmacokinetic data, a clear dependency of EE2 concentration curves on the estrogen dose of the respective preparation could be demonstrated. Under the condition of steady-state (21st day of administration) there was a slight but significant rise of the EE2 peak serum concentrations and a pronounced increase of the LNG levels, closely reflected by elevation of the AUC values. SHBG serum concentration was significantly increased by the 10th day of treatment in all subjects receiving Gravistat, whereas the mean value in the Minisiston-group did not remarkably change. Although LNG is known to be bound to SHBG with high affinity, the missing parallelism between LNG- and SHBG-concentrations suggests other (additional?) mechanisms for the elevated LNG-binding capacity in women taking combined EE2-LNG preparations.

Simultaneous Estradiol and Levonorgestrel Transdermal Delivery from a 7-day Patch: In Vitro and In Vivo Drug Deliveries of Three Formulations

A new drug-in-adhesive transdermal patch was developed to deliver both estradiol and levonorgestrel through the skin over a 7-day period, but at different rates. This report elucidates the in vitro and in vivo biopharmaceutical studies that were necessary during the development of this product. Three test patches had to be manufactured, all delivering estradiol at the same rate, but delivering levonorgestrel at three different rates so that a levonorgestrel dose response could be studied in the clinic. An in vitro hairless mouse skin model (HMS) using modified Franz diffusion cells was used to select the test products delivering levonorgestrel in the order of 1:2:3. HMS experiments also demonstrated that the presence of estradiol did not affect the flux of levonorgestrel. Two in vivo studies in postmenopausal women showed that at steady state (four weeks of once-weekly dosing) the three test products all delivered estradiol at comparable rates. Similarly, the levonorgestrel deliveries for the three test products were in the order expected. The target fluxes of both drugs were achieved in these three test products by varying the drug loads and patch size. That this approach was successful is evidence of the value of using the HMS penetration experiments in transdermal product development and should provide useful insights for other formulations having to develop complex systems. One of the test products is now marketed as Climara Pro.

Pharmacokinetics of a single oral dose of 1.5-mg levonorgestrel when administered as 750-μg tablets or as 30-μg minipills

We examined the pharmacokinetics of a single dose of 1.5 mg of levonorgestrel when administered orally in two different formulations: two tablets of 0.75 mg or 50 minipills of 30 microg of levonorgestrel. Bioavailability of levonorgestrel with minipills was comparable to that with levonorgestrel tablets. These findings suggest that levonorgestrel-containing minipills can be considered as an alternative to standard levonorgestrel tablets for use in emergency contraception.

Modern management of abnormal uterine bleeding: the levonorgestrel intra-uterine system

Since its launch, more than 9 million women worldwide have used the levonorgestrel intra-uterine system (IUS) for contraception, as a treatment for heavy menstrual bleeding and as the progestogen component of hormone-replacement therapy. For women in their reproductive years, the IUS has become one of the most acceptable medical treatments for menorrhagia, reducing referrals to specialists and decreasing the need for operative gynaecological surgery. This article will outline the development of the IUS, highlighting the most important recent areas of research covering its use to control menstrual blood loss and pain.

Pharmacokinetic study to compare the absorption and tolerability of two doses of levonorgestrel following single vaginal administration of levonorgestrel in Carraguard gel: a new formulation for "dual protection" contraception

OBJECTIVE

The study was conducted to assess levonorgestrel (LNG) serum levels achieved after a single administration of two different doses of Carraguard vaginal gel containing LNG (CARRA/LNG), designed for use as microbicide and contraceptive for potential dual protection.

MATERIALS AND METHODS

This was a randomized double-blind pharmacokinetic study conducted in 12 subjects enrolled at two centers. Each subject received a single vaginal administration of CARRA/LNG containing either 0.75 or 1.5 mg LNG per 4 mL of gel on Days 10-12 of the menstrual cycle. LNG serum levels were measured at 0, 1, 2, 4, 8 and 12 h after administration and for the following 7 days. LH and progesterone (for a preliminary evaluation of effect on the ovarian function) as well as SHBG were measured in the daily samples.

RESULTS

Serum LNG maximum concentrations (Cmax) were 14.1+/-2.1 and 11.7+/-2.7 nmol/L and Tmax was 12.0 and 6.0 h for the low and high dose, respectively, with large intersubject variability within the first 48 h. Mean levels at 96 h were 10% of Cmax. Differences in AUC between both doses were not statistically significant. SHBG levels decreased approximately 25% by Day 4 after administration. Luteal activity was observed in 3/6 and 5/6 of the subjects in the low- and high-dose group, respectively.

CONCLUSION

This study demonstrates that the CARRA/LNG gel can sustain elevated serum levels of the contraceptive steroid for up to 96 h after a single application. The serum levels attained with the 0.75-mg formulation are in the range expected to perturb the ovulatory process as observed in some subjects. The lack of correlation between the administered dose and serum concentrations of the steroid may be related to a rate-limiting absorption of LNG from the vaginal mucosa. The results reported here suggest that the CARRA/LNG formulation has good potential to become a dual-protection method, possibly preventing conception and sexually transmitted infections.

Pharmacokinetics and pharmacodynamics of sterylglucoside-modified liposomes for levonorgestrel delivery via nasal route

For emergency contraceptive, the rapid delivery of levonorgestrel (LNG) to plasma is desirable, furthermore, a sustained delivery of LNG along with rapid absorption will be necessary. The pharmacokinetics and pharmacodynamics of LNG entrapped in different kinds of liposome formulations via nasal administration in rats were evaluated and compared with LNG suspension via the oral route. The relative bioavailabilities of these liposome formulations via nasal administration were 100% or higher than 100%. The Cmax and Tmax values of sterylglucoside (SG) and chitosan-contained formulations by nasal administration were 416.84 ng/mL and 1.02 hr, 227.97 ng/mL and 2.02 hr, respectively, compared with that of 334.94 ng/mL and 1.89 hr of oral suspension. Fully 100% contraception was observed for all the formulations. SG could promote the absorption of LNG via the nasal route and may provide a rapid onset of action of LNG for emergency contraception. Chitosan could retain LNG in the nasal cavity for long contact time to sustain delivery of LNG. The rapid onset and sustained delivery of LNG can be achieved via the nasal route using liposomes as the vehicle.

Levonorgestrel pharmacokinetics in plasma and milk of lactating women who take 1.5 mg for emergency contraception

BACKGROUND

Progestin-only methods are among the contraceptive options available for breastfeeding women, however the doses of progestin used in emergency contraception (EC) have not been evaluated in nursing mothers. We therefore investigated the pharmacokinetics of 1.5 mg levonorgestrel (LNG) in lactating women.

METHODS

Twelve healthy exclusively breastfeeding volunteers received 1.5 mg LNG. Women refrained from nursing for 72 h after dosing and fed their infants with milk frozen beforehand. Serial blood and milk samples were collected for 120 h and assayed for LNG and sex hormone binding globulin.

RESULTS

LNG concentrations peaked in plasma and in milk 1-4 h and 2-4 h after dosing, respectively. Concentrations in milk (M) paralleled those in plasma (P) but were consistently lower (mean M:P ratio 0.28). Estimated infant exposure to LNG is 1.6 microg on the day of dosing (1 microg in the first 8 h), 0.3 microg on the second day and 0.2 microg on the third day.

CONCLUSIONS

Nursing mothers may need EC. These results suggest that to limit infant exposure to the period of maximum LNG excretion in milk, mothers should discontinue nursing for at least 8 h, but not more than 24 h, after EC.

Levonorgestrel-Only Dosing Strategies for Emergency Contraception

The United States Food and Drug Administration-approved progestin-only dosing strategy for emergency contraception is levonorgestrel 0.75 mg taken as soon as possible within 72 hours of unprotected intercourse, with a second 0.75-mg dose taken 12 hours later. However, different dosing strategies have been studied and promoted by various organizations. The American College of Obstetricians and Gynecologists recommends a single dose of levonorgestrel 1.5 mg for emergency contraception as one option. As another option, they recommend two doses of levonorgestrel 0.75 mg may be effective when taken 12-24 hours apart. We performed a search of MEDLINE and International Pharmaceutical Abstracts from 1967-2006 to evaluate and describe the existing pharmacokinetic and patient outcome data regarding administration of levonorgestrel as a 1.5-mg single dose or two 0.75-mg doses taken 12 or 24 hours apart. Additional studies were identified from the bibliographies of the selected literature. Several pertinent articles were identified. All of the studies demonstrated that emergency contraception effectively prevented pregnancy. In addition, evidence supports the safety and efficacy of a single dose of levonorgestrel 1.5 mg for emergency contraception. Furthermore, when two doses of levonorgestrel 0.75 mg are administered, the second dose can confidently be taken 12-24 hours after the first without compromising efficacy. Understanding the evidence that supports the different emergency contraception dosing strategies is critical for clinicians, and especially pharmacists, who have interactive roles in dispensing emergency contraception.

A semi-automated 96-well plate method for the simultaneous determination of oral contraceptives concentrations in human plasma using ultra performance liquid chromatography coupled with tandem mass spectrometry

Two semi-automated, relatively high throughput methods using ultra performance liquid chromatography coupled with tandem mass spectrometry (UPLC-MS/MS) were developed for the simultaneous determination of ethinyl estradiol (EE) in combination with either 19-norethindrone (NE) or levonorgestrel (LN) in human plasma. Using 300 microL plasma, the methods were validated over the concentration ranges of 0.01-2 ng/mL and 0.1-20 ng/mL for EE and NE (or LN), respectively. The existing methods for the determination of the oral contraceptives in human plasma require large volumes of plasma (> or =500 microL), and sample extraction is labor-intensive. The LC run time is at least 6 min, enabling analysis of only about 100 samples a day. In the present work the throughput was greatly improved by employing a semi-automated sample preparation process involving liquid-liquid extraction and derivatization with dansyl chloride followed by UPLC separation on a small particle size column achieving a run time of 2.7 min. The validation and actual sample analysis results show that both methods are rugged, precise, accurate, and well suitable to support pharmacokinetic studies where approximately 300 samples can be extracted and analyzed in a day.

Influence of avosentan (SPP301) on the pharmacokinetics of a second generation oral contraceptive containing ethinylestradiol and levonorgestrel in healthy female volunteers

BACKGROUND

Avosentan (SPP301) is a potent and highly selective ETA receptor blocker and is clinically investigated in diabetic nephropathy. This study was designed to evaluate whether avosentan influences the pharmacokinetics of steroid oral contraceptives.

METHODS

During a run-in phase, 16 healthy females received an oral contraceptive containing ethinylestradiol 0.03 mg and levonorgestrel 0.15 mg for the first 21 days of a minimum of one menstrual cycle. In a subsequent double-blind, randomized two menstrual cycle crossover treatment phase, subjects received either avosentan 25 mg or placebo once daily concomitantly with the oral contraceptive. Serum ethinylestradiol and plasma levonorgestrel concentrations were measured on Days 14 and 15 of the two treatment periods for the evaluation of the 24-hour kinetic parameters, and an additional sample was collected on Day 21 to determine their trough concentrations. Serum progesterone, luteinizing hormone (LH) and follicle-stimulating hormone (FSH) levels as well as plasma avosentan and Ro 68-5925 levels were determined on Days 13, 14, 15 and 21 of each cycle of the treatment phase.

RESULTS

Avosentan had a statistically significant lowering effect of 9 - 15% on the ethinylestradiol serum concentration levels. The 90% confidence intervals of the pharmacokinetic parameters did not include 1 or exceeded the 0.8 - 1.25 acceptance range for lack of interaction. The plasma concentration-time curves and pharmacokinetic parameters of levonor-gestrel were not statistically different during concomitant treatment with either avosentan or placebo. Compared to placebo, avosentan lowered the serum concentrations of progesterone statistically significantly by about 8% and increased slightly the LH and FSH serum concentrations. Safety and tolerability patterns were comparable during avosentan and placebo administration.

CONCLUSION

Because of the effect of avosentan on the concentration levels of ethinylestradiol and progesterone, it is possible that the contraceptive efficacy of low-dose combination oral contraceptives may be adversely affected during avosentan treatment.

Pharmacokinetic interaction of solifenacin with an oral contraceptive containing ethinyl estradiol and levonorgestrel in healthy women: a double-blind, placebo-controlled study

BACKGROUND

Solifenacin succinate (YM905; Vesicare, Astellas Pharma Inc., Tokyo, Japan) is a new once-daily, orally administered muscarinic receptor antagonist under investigation for the treatment of overactive bladder.

OBJECTIVE

The aim of this study was to evaluate the effect of solifenacin on the pharmacokinetic (PK) parameters of an oral contraceptive (OC) containing ethinyl estradiol (EE) and levonorgestrel (LNG).

METHODS

In a double-blind, placebo-controlled, 2-period, crossover study, 24 healthy, young, white women received a combined OC (EE 30 microg + LNG 150 microg) daily for two 21-day cycles, separated by a 7-day washout. On day 12 of each cycle, subjects began a 10-day regimen of solifenacin 10 mg QD, which is 2 times the suggested starting dose, or placebo. Subjects crossed over to the other treatment arm for the second cycle. Primary PK end points were C(max) and AUC from time 0 to 24 hours (AUC(0-24 h)) for EE and LNG. Women ranged in age from 20 to 37 years and had a mean body weight of 64 kg, mean height of 167.4 cm, and mean body mass index of 23 kg/m2. Seven women had never smoked, while 5 were former smokers and 12 were regular smokers. Safety assessments included the nature, frequency, and severity of spontaneously reported or observed adverse events, vital signs, electrocardiogram, laboratory values, and physical examination.

RESULTS

Statistical analysis of AUC(0-24 h)/product of baseline concentration and total blood sampling time, and C(max)/baseline concentration ratios of solifenacin versus placebo for EE and LNG found the 90% CI to be within the predefined range of 0.8 to 1.25 (EE: 0.854-1.164 and 0.822-1.167; LNG: 0.920-1.125 and 0.910-1.139). The number of samples with non-quantifiable luteinizing hormone (LH) and folliclestimulating hormone (FSH) levels were comparable after administration of the OC with either solifenacin or placebo. The adverse event most frequently reported was dry mouth (solifenacin, n = 25 [9 mild, 13 moderate, and 3 severe] vs placebo, n = 1 [moderate]). There were no clinically relevant effects on vital signs, electrocardiogram, or laboratory parameters.

CONCLUSIONS

A PK interaction between solifenacin and the OC containing EE and LNG was not found in this study. Solifenacin was not found to have altered suppression of LH or FSH. The drug was well tolerated in these healthy, young, white, adult female volunteers.

Pharmacokinetics of single-dose levonorgestrel in adolescents

PURPOSE

The purpose of this study is to compare the pharmacokinetics of levonorgestrel, a drug used for emergency contraception between female adolescents and adults.

METHODS

Twenty-two female subjects, aged 13-16 years, received a single 0.75-mg dose of the drug. Serial blood samples were collected for 72 h and used to measure plasma levonorgestrel concentrations. Previously published data from 16 adults, aged 18-45 years, served as comparison.

RESULTS

There was a statistically significant higher total plasma clearance divided by the bioavailability (CL/F) of levonorgestrel in adolescents compared to adults, resulting in lower maximum and average total plasma concentrations. There was a trend for a larger volume of distribution divided by bioavailability (V/F), but there was no significant difference in the half-life of levonorgestrel in adolescents relative to adults (p=.098).

CONCLUSION

The differences between adolescents and adults are unlikely to be clinically significant because specific changes in total concentrations suggest that unbound concentrations are probably not affected. Furthermore, empirically high doses of levonorgestrel are given for emergency contraception.

A biodegradable levonorgestrel-releasing implant made of PCL/F68 compound as tested in rats and dogs

PURPOSE

Our objective was to report preclinical studies on a biodegradable long-acting contraceptive implant.

METHODS

A poly (epsilon-caprolactone) (PCL)/pluronic F68 (F68) compound was used to construct an implant, which was filled with dry levonorgestrel (LNG) powder (PCL/F68/LNG). LNG release rate, contraceptive efficacy and polymer degradation were evaluated in rats and followed for 2 years. A 2-year toxicity study was conducted in dogs.

RESULTS

The in vitro and in vivo release of LNG from the implant followed zero-order release kinetics. Serum LNG level in rats was very stable during the 2-year period. Studies on polymer degradation indicated that the molecular weight of PCL dropped from 66,000 to 15,000 Da, but the implant was still in good shape by the end of 2 years.

CONCLUSION

Toxicological study demonstrated that the PCL/F68 polymer had no adverse effect in all aspects. The contraceptive efficacy in rats showed dose response. The implant was physically and chemically stable for up to 3 years in airproof aluminum foil packing at room temperature.

The levonorgestrel-releasing intrauterine system (LNG-IUS) in HIV-infected women—effects on bleeding patterns, ovarian function and genital shedding of HIV

BACKGROUND

Safe and effective contraceptives are needed for human immunodeficiency virus (HIV)-infected women. The levonorgestrel-releasing intrauterine system (LNG-IUS) is a highly effective contraceptive with additional health benefits. The objective of this study was to evaluate the effects of the LNG-IUS among HIV-infected women.

METHODS

Twelve systematically managed HIV-infected women were studied prospectively. Following a 2-month run-in period, the subjects had an LNG-IUS inserted and were followed up for 1 year. Patterns of bleeding, blood haemoglobin and CD4-lymphocyte content, plasma HIV RNA, serum levels of LNG, of estradiol (E(2)) and of ferritin and genital shedding of HIV RNA were monitored.

RESULTS

Menstrual bleeding was reduced significantly during the use of the LNG-IUS; this was associated with slight increases in serum haemoglobin and ferritin levels. Serum E(2) concentrations remained in the follicular range in all subjects. Among subjects using antiretroviral medication, the proportion of cervicovaginal lavage specimens with detectable HIV RNA was 10% before and after the insertion of the LNG-IUS.

CONCLUSIONS

The effects of the LNG-IUS on bleeding patterns, body iron stores and ovarian function were similar to those seen in healthy women. Genital shedding of HIV RNA was not affected by the LNG-IUS. These data encourage further studies on the effects of the LNG-IUS on reproductive health among HIV-infected women.

Effects of Jadelle used in Thai women aged between 20 and 45 years in King Chulalongkorn Memorial Hospital

OBJECTIVE

To study the menstrual patterns and side effects of Jadelle use in Thai women aged between 20 and 45 years.

STUDY DESIGN

Prospective descriptive study.

SETTING

Family Planning Clinic, Department of Obstetrics and Gynecology, King Chulalongkorn Memorial hospital.

MATERIAL AND METHOD

A prospective clinical trial study was conducted at the Family Planning Unit, King Chulalongkorn Memorial Hospital in June 2005. The study duration was 6 months. The data was obtained from each patient S medical record. The descriptive statistics was frequency, percentage, mean, SD and 95% Confidence Interval (CI). The statistical analyses were performed by using the paired t test for comparison of means before and after 6 months of Jadelle used.

RESULTS

A total of 59 women were recruited in a 6-month clinical study. Their mean age was 29.07years. Most acceptors had completed secondary school. No accidental pregnancy occurred throughout the 6 months of use in the present study. The most common menstrual pattern was amenorrhea followed by irregular bleeding. The major side effect was irregular bleeding. There was no significant change in body weight, body mass index, and systolic-diastolic blood pressure during the 6 months follow up period. The common non menstrual adverse effects were headache, acne, alopecia.

DISCUSSION

The most common menstrual patterns found in the present study were amenorrhea and irregular bleeding followed by a regular cycle. The common nonmenstrual adverse effects were headache, acne, and alopecia. There were no pregnancies in the 6-month follow-up period. Jadelle was an effective implant contraceptive method with an acceptable bleeding pattern. Over all acceptability was good. This should become another choice of contraception for Thai women.

Controlled release of levonorgestrel from biodegradable poly(D,L-lactide-co-glycolide) microspheres: in vitro and in vivo studies

Poly(D,L-lactide-co-glycolide) (PLG) biodegradable microspheres containing a contraceptive drug, levonorgestrel (LNG), were prepared using both the solvent evaporation method and a modified solvent extraction-evaporation method. The microspheres prepared with the solvent evaporation process had porous surfaces with low product yields and poor encapsulation efficiencies. On the other hand, the microspheres prepared using the modified solvent extraction-evaporation method were nonporous with encapsulation efficiencies close to 100%. In vitro drug release showed the nonporous microspheres had a lower initial burst and a slightly prolonged duration of release than those porous microspheres. In vivo release kinetics of the low burst microspheres were determined by measuring LNG plasma levels after a single intramuscular injection to female rats. At a LNG dose of 41.1 mg/kg, average plasma LNG levels were 6-10 ng/ml in the first 24 h and subsequently remained above 1 ng/ml until 126 days. The duration above the minimum effective LNG plasma level of 0.2 ng/ml was 168 days. By comparison, a similar dose of LNG microcrystals used as control produced a much higher plasma level of 15-21 ng/ml in the first day followed by a fast and continuous decline of LNG levels with a duration of only about 35 days.

Bioavailability of the Yuzpe and levonorgestrel regimens of emergency contraception: vaginal vs. oral administration

Separate crossover studies compared the bioavailability of oral vs. vaginal routes of administration for the Yuzpe (n=5) and levonorgestrel regimens (n=4) of emergency contraception. Twice the standard dose of the Yuzpe regimen (200 microg of ethinyl estradiol, 1000 microg of levonorgestrel) or the levonorgestrel regimen (1500 microg of levonorgestrel) was self-administered vaginally. One week later, each subject received orally the standard dose of the assigned medication. Serial blood samples were collected over 24 h and assayed for levonorgestrel and ethinyl estradiol (for the Yuzpe regimen only). Paired t tests were used to compare oral vs. vaginal administration for maximum concentration (Cmax), time to maximum concentration (Tmax) and area under the curve over 24 h (AUC0-24). Relative bioavailability (vaginal/oral) was derived from AUC0-24. Vaginal administration of double the standard dose of the Yuzpe regimen resulted in a lower Cmax (vaginal=5.4 vs. oral=14.6 ng/mL, p=.038) and a later Tmax (5.9 vs. 2.0 h, p=.066) for levonorgestrel, compared to oral administration. Corresponding ethinyl estradiol concentrations were higher (786 vs. 391 pg/mL, p=.039) and peaked later (4.0 vs. 1.9 hr, p=.154) with vaginal administration. Relative bioavailabilities for levonorgestrel and ethinyl estradiol were 58% and 175%, respectively. Similarly, vaginal administration of the levonorgestrel regimen resulted in a lower Cmax (vaginal=5.4 vs. oral=15.2 ng/mL, p=.006) and a later Tmax (7.4 vs. 1.3 h, p=.037) for levonorgestel, compared to oral administration. The relative bioavailability was 62%. Our preliminary data suggest that vaginal administration of these emergency contraception regimens appears to require at least three times the standard oral dose to achieve equivalent systemic levonorgestrel concentrations.

Proultraflexible lipid vesicles for effective transdermal delivery of levonorgestrel: development, characterization, and performance evaluation

The present investigation aimed at formulation, performance evaluation, and stability studies of new vesicular drug carrier system protransfersomes for transdermal delivery of the contraceptive agent, levonorgestrel. Protransfersome gel (PTG) formulations of levonorgestrel were prepared and characterized for vesicle shape, size, entrapment efficiency, turbidity, and drug permeation across rat skin and were evaluated for their stability. The system was evaluated in vivo for biological assay of progestational activity including endometrial assay, inhibition of the formation of corpora lutea, and weight gain of uterus. The effects of different formulation variables (type of alcohol, type and concentration of surfactant) on transdermal permeability profile were assessed. The optimized PTG formulation showed enhanced in vitro skin permeation flux of 15.82 +/- 0.37 microg/cm2/hr as compared to 0.032 +/- 0.01 microg/cm2/hr for plain drug solution. PTG also showed good stability and after 2 months of storage there was no change in liquid crystalline nature, drug content, and other characteristic parameters. The peak plasma concentration of levonorgestrel (0.139 +/- 0.05 microg/mL) was achieved within 4 hours and maintained until 48 hours by a single topical application of optimized PTG formulation. In vivo performance of the PTG formulation showed increase in the therapeutic efficacy of drug. Results indicated that the optimized protransfersomal formulation of levonorgestrel had better skin permeation potential, sustained release characteristic, and better stability than proliposomal formulation.

[Effect of levonorgestrel-releasing intrauterine system in the treatment of adenomyosis]

OBJECTIVE

To assess the clinical efficacy of levonorgestrel-releasing intrauterine system (LNG-IUS) in the treatment of adenomyosis.

METHODS

Forty-two patients with adenomyosis diagnosed by clinical symptoms, MRI, laparoscopy and/or chromatic colour type-B ultrasound were treated with LNG-IUS, and the menstrual blood volume, severity of dysmenorrhea and uterine volume were observed three months later.

RESULTS

After 3 month treatment of LNG-IUS, the menstrual blood volume reduced significantly to (27 +/- 11)% of that before treatment. The uterine volume was decreased from (143 +/- 33) cm(3) to (115 +/- 22) cm(3) (P < 0.05). Dysmenorrhea was completely relieved or significantly alleviated. Hemoglobin recovered to (124 +/- 8) g/L (P < 0.05) in 20 patients with anemia.

CONCLUSION

LNG-IUS is an effective and safe method in the short-term treatment of adenomyosis.

Pharmacokinetics and endometrial tissue levels of levonorgestrel after administration of a single 1.5-mg dose by the oral and vaginal route

OBJECTIVE

To determine the pharmacokinetics and endometrial tissue levels of levonorgestrel when taken as a single dose of 1.5 mg either orally or vaginally by healthy women in the periovulatory phase of their menstrual cycle.

DESIGN

Prospective randomized study.

SETTING

Academic research institution.

PATIENT(S)

Thirty women with regular cycles allocated to control (n = 5), oral (n = 13), and vaginal (n = 12) groups.

INTERVENTION(S)

Blood samples were drawn before (0 time) and at 0.5, 1, 2, 4, 6, 8, 24, 48, and 168 hours after levonorgestrel administration. Endometrial samples were collected 24 and 168 hours after levonorgestrel administration.

MAIN OUTCOME MEASURE(S)

Plasma and endometrial tissue levels of levonorgestrel.

RESULT(S)

Plasma concentrations of levonorgestrel were significantly greater during the first 48 hours after oral administration. However, 7 days after levonorgestrel administration, the plasma levels were similar for both treatments (3-5 nmol/L). Compared with vaginal administration, oral administration resulted in higher peak plasma concentrations (Cmax 64 vs. 10.7 nmol/L), with a shorter time to reach the maximal concentrations (Tmax 1.4 vs. 6.6 hours) and with a greater AUC (509 vs. 175 nmol/L). Interestingly, the half-life of levonorgestrel was shorter after oral administration (25 hours vs. 32.6 hours). Levonorgestrel tissue concentrations were not related to the plasma levels. Levonorgestrel values tended to be higher in endometrial tissue after vaginal administration. The ratio between plasma and endometrial concentrations of levonorgestrel differed significantly between the groups.

CONCLUSION(S)

These data indicate that orally administered levonorgestrel achieves higher plasma levels sooner than vaginally administered levonorgestrel. However, plasma levels after vaginal administration are more sustained and were likely to be sufficient for ovarian suppression. Therefore, the vaginally administered levonorgestrel could be considered as an alternative option for emergency contraception.

Serum and peritoneal fluid levels of levonorgestrel in women with endometriosis who were treated with an intrauterine contraceptive device containing levonorgestrel

OBJECTIVE

To determine and compare levels of levonorgestrel (Lng) in serum and peritoneal fluid (PF) of patients on the Lng intrauterine system Mirena (Schering Health, Berlin, Germany) for endometriosis and to relate these to symptoms.

DESIGN

Prospective clinical trial.

SETTING

Gynecology unit of a teaching hospital.

PATIENT(S)

Women with minimal to moderate endometriosis at diagnostic laparoscopy.

INTERVENTION(S)

Mirena was inserted at diagnostic laparoscopy and blood and PF collected for Lng levels. Levonorgestrel was again quantified in serum at 1, 3, and 6 months and PF at 6 months.

MAIN OUTCOME MEASURE(S)

Serum and PF Lng levels during 6 months, differences in levels before and 6 months after Mirena insertion, and the relationship between these levels and symptoms of endometriosis.

RESULT(S)

There was significant improvement in symptoms after 6 months on Mirena. The mean (SD) serum Lng levels were 459.2 (100.2), 368.2 (51.8), and 357.3 (53.0) pg/mL at 1, 3, and 6 months, respectively. The PF levels at 6 months were approximately two-thirds the serum levels in patients showing improvement in symptoms.

CONCLUSION(S)

Mirena delivers significant amounts of Lng into the PF and serum. The relationship between Lng levels in these compartments is linear.

Ovarian function with the contraceptive vaginal ring or an oral contraceptive: a randomized study

BACKGROUND

The effects on ovarian function of the combined contraceptive vaginal ring NuvaRing and a combined oral contraceptive (COC) were compared.

METHODS

This randomized, open-label study was performed in 40 healthy female volunteers, who were randomized by a computer-generated list after stratification for the ovulation day in a pretreatment cycle. They received two cycles of NuvaRing (21 subjects) or a COC (30 microg ethinylestradiol and 150 microg levonorgestrel, 19 subjects). NuvaRing was started on cycle day 5, COC on cycle day 1. Follicular diameter, endometrial thickness and FSH, LH, 17beta-estradiol (E2) and progesterone concentrations were determined.

RESULTS

The median maximum follicular diameter (maxFD) was < or =11 mm during treatment. In the first treatment cycle the maxFD was lower in the COC than in the NuvaRing group, due to the different starting procedures. MaxFD were not different in the second treatment cycle. In both groups, E2 and progesterone levels remained low during treatment. Ovulations did not occur.

CONCLUSIONS

In both groups, ovarian activity was adequately suppressed. Due to the different starting procedures, lower ovarian activity was observed in the COC group in the first treatment cycle. In the second cycle, ovarian suppression was comparable with NuvaRing and COC treatment.

Bioequivalence study of postcoital emergency contraceptions containing levonorgestrel

OBJECTIVE

The progestogen-only method of emergency contraception, levonorgestrel, is one of the effectiveness in preventing expected pregnancies. The comparative bioavailability was carried out on levonorgestrel tablets (0.75 mg) from two different sources (Hungarian and Thai made).

METHOD

Eighteen healthy female volunteers were given a single oral dose of 0.75 mg tablets in a crossover design. Serum levonorgestrel concentration was determined by radio-immunoassay. The pharmacokinetic analysis of serum levonorgestrel concentration from each treatment was established. The comparative bioavailability of the two products was determined by the analysis of variance (ANOVA) for two way crossover design.

RESULTS

The results found that the mean peak (X +/- SD) serum concentration (Cmax) of the Thai-made pill and Hungarian-pill were 1.18 +/- 0.12 and 1.14 +/- 0.10 ng/ml, respectively. The 90% confidence intervalfor the difference of log Cmax mean was 99.54-120.78%. The time to peak serum concentration (Tmax) of the Thai-made pill and Hungarian-pill were 1.56 +/- 0.73 and 1.58 +/- 0.67 hrs, respectively. The different time of peak serum levonorgestrel concentration was 1.27%. The mean area under the curve (AUC) of Thai-made pill and Hungarian-pill were 2.14 +/- 0.21 and 2.09 +/- 0.16 ng.h/ml, respectively. The 90% confidence interval for the difference of log AUC mean was 103.27 - 121.89%.

CONCLUSION

The present study revealed that the 90% confidence interval for the difference of log Cmax mean and log AUC mean were in the criteria of acceptance, which should be within 80-125%. So, the authors can conclude that the Thai-made pill was bioequivalent to the Hungarian-pill.

Pharmacodynamics and pharmacokinetics of oral contraceptives co-administered with alosetron (Lotronex)

The 5-HT3 receptor antagonist alosetron (Lotronex) is indicated for use in women with severe, chronic, diarrhea-predominant irritable bowel syndrome (IBS) who have failed conventional therapy. Oral contraceptives (OCs) and alosetron are potential co-medications in women of childbearing age. This study assessed the effect of alosetron co-administration on pharmacodynamic markers of contraceptive efficacy, on the pharmacokinetics of estrogen and progesterone OC components, and on the activity of biochemical markers for the risk of thrombosis. This was an open label, nonrandomized two-way crossover study in 18 healthy women stabilized for 3 months on a low-dose OC containing ethinyl estradiol (EE) and levonorgestrel (LN). Alosetron had no effect on serum concentrations of luteinizing hormone (LH) or follicle-stimulating hormone. Ovarian activity grades (assessing follicle size, progesterone, and 17beta-estradiol concentrations) were similar during OC use with and without alosetron. Steady-state (Day 21) AUC24, Cmax, and tmax of both LN and EE were similar during coadministration of alosetron with an OC. Concentrations and activity of biochemical markers of thrombosis risk were not different in the presence of alosetron. These results indicate that alosetron does not alter the pharmacokinetics or pharmacodynamic markers of efficacy for a low-dose combination OC. The results also suggest that thromboembolic risk is not increased when alosetron is co-administered with an OC.

Pulmonary absorption of liposomal levonorgestrel

The purpose of these studies was to achieve desired bioavailability after pulmonary administration of Levonorgestrel (LN) and to provide prolonged effective concentration of the drug in plasma and to reduce reported side effects of orally administered drug. The plain drug suspension, physical mixture (plain drug with liposomal constituents), and drug-encapsulated liposomes containing 10 micro g of drug were instilled intratracheally in rats. Similarly, 10- micro g drug suspension (LO) was administered orally. The blood samples were withdrawn at specific time intervals and were subjected to LN analysis by spectrofluorimetric technique. The plasma drug concentration data of both the treatments were plotted, and pharmacokinetics data were calculated and compared with that of oral administration. Percentage relative bioavailability (F*) of 97.6%, 98.6%, and 109.9% were observed after pulmonary administration of plain drug formulation (LP1), physical mixture (plain drug along with constituents of liposomes [LP2]), and liposomal (LP3) formulations of the drug, respectively. Following oral administration, Cmax of 14.4 +/- 0.6 ng/mL was observed at 2.1 +/- 0.2 hours followed by subtherapeutic concentration beyond 30 +/- 0.2 hours, while after pulmonary administration of LP1, LP2, and LP3 formulations, Cmax of 4.4 +/- 0.4 ng/mL, 4.2 +/- 0.5 ng/mL, and 4.4 +/- 0.6 ng/mL were observed at 6.0 +/- 0.2 hours, 7.0 +/- 0.2 hours, and 6.8 +/- 0.2 hours, respectively, followed by maintenance of effective plasma drug concentration up to 60 +/- 2 hours. These studies demonstrate superiority of pulmonary drug delivery with regards to maintenance of effective therapeutic concentration of the LN in the plasma over a period of 6 to 60 hours. Hence, the pulmonary delivery is expected to reduce frequency of dosing and systemic side effects associated with oral administration of LN.

Hormonal contraception in Chinese men: variations in suppression of spermatogenesis with injectable testosterone undecanoate and levonorgestrel implants

AIM

To explore the causes of the difference in spermatogenic suppression between responders and non-responders in Chinese men treated with levonorgestrel (LNG) implants plus testosterone undecanoate (TU) injectable.

METHODS

The 16 Chinese volunteers treated were divided into two groups in regard to the sperm count during the treatment period, 7 men in the responder group (Group R), including 6 azoospermia and one severe oligozoospermia, and the remaining 9 in the non-responder group (Group N), including 4 oligozoospermia and 5 with sperm counts greater than 20 x 10(6)/mL. The differences in serum profiles of FSH, LH, T, LNG and T/LH ratio were compared between the two groups and the correlation between the seminal fluid parameters and serum reproductive hormones was analyzed.

RESULTS

The serum FSH level was lower in Group R than that in Group N (P<0.05), while the serum LH and LNG levels were higher in Group R than those in Group N (P<0.05). The sperm density (P<0.01, r=0.235), motility(P<0.01, r=0.326) and vitality (P<0.01, r=0.219) showed significantly positive correlation with the serum FSH level.

CONCLUSION

The blood LNG and T levels, the degree of FSH inhibition and/or the sensitivity of the pituitary-testis axis to exogenous steroids, as well as the individual spermatogenetic potential and the functional status of the Leydig cells may be factors bringing about individual differences in spermatogenic suppression in Chinese men treated with LNG and TU.

Nasal delivery of levonorgestrel for contraception: an experimental study in rats

OBJECTIVE

To ascertain the nasal bioavailability of Levonorgestrel and change formulation components to provide long-term effective concentrations of the drug in blood. An experimental study was conducted on rats to reduce dose and/or frequency of drug administration to reduce expected side effects reported in humans.

DESIGN

In vivo study in rats.

SETTING

Centre of Relevance & Excellence in new drug delivery systems, Pharmacy Dept., G.H. Patel Budg., Faculty of Technology and Engineering, M.S. University of Baruda, Fatehgunj, Vadodara, Gujarat, India.

ANIMAL(S)

Rats of proven fertility.

INTERVENTION(S)

Formulations containing 10-microg of levonorgestrel were administered in rats via the nasal route. Similarly, a 10-microg drug suspension was administered orally. The influence of the mucoadhesive agents chitosan and carbopol 934p on nasal absorption of the drug was also evaluated.

MAIN OUTCOME MEASURE(S)

Plasma drug concentration and pharmacokinetics.

RESULT(S)

Relative bioavailabilities of 29.93%, 32.14%, and 25.97% were observed after nasal administration of plain drug, physical mixture, and liposomal formulations, respectively. Mucoadhesive agents in nasal formulations were found to produce a threefold increase in drug bioavailability. Bioavailability was improved from 29.93% to 101.70% and 99.42%, respectively, for chitosan (0.5%) and carbopol 934p (0.5%) formulations, with a significantly improved plasma half life from 7.0 hours to 55.7 hours and 52.9 hours, respectively. Pharmacodynamic studies indicate that the dosing interval can be changed from daily oral administration to nasal administration once every 2 days without changing the dose.

CONCLUSION(S)

Levonorgestrel with mucoadhesive agents administered nasally in rats is superior for maintaining effective drug concentrations over an extended period of time when compared with the presently available orally administered form.

Benefit-Risk Assessment of the Levonorgestrel Intrauterine System in Contraception

The levonorgestrel-releasing intrauterine system (IUS) is a long-acting, fully reversible method of contraception. It is one of the most effective forms of contraception available, and combines the advantages of both hormonal and intrauterine contraception. The levonorgestrel-releasing IUS also gives the users many non-contraceptive benefits: the amount of menstrual bleeding and the number of days of menstrual bleeding are reduced, which makes it suitable for the treatment of menorrhagia (heavy menstrual blood loss). Dysmenorrhoea (painful menstruation) and premenstrual symptoms are also relieved. In addition, the levonorgestrel-releasing IUS provides protection for the endometrium during hormone replacement therapy. The local release of levonorgestrel into the uterine cavity results in a strong uniform suppression of the endometrial epithelium as the epithelium becomes insensitive to estradiol released from the ovaries. This accounts for the reduction in menstrual blood loss. All possible patterns of bleeding are seen among users of the levonorgestrel-releasing IUS; however, most of the women who experience total amenorrhoea continue to ovulate. The first months of use are often characterised by irregular, scanty bleeding, which in most cases resolves spontaneously. The menstrual pattern and fertility return to normal soon after the levonorgestrel-releasing IUS is removed. The contraceptive efficacy is high with 5-year failure rates of 0.5-1.1 per 100 users. The absolute number of ectopic pregnancies is low, as is the rate per 1000 users. The levonorgestrel-releasing IUS is equally effective in all age groups and the bodyweight of the user is not associated with failure of the method. In Western cultures continuance rates among users of the levonorgestrel-releasing IUS are comparable with those of other long-term methods of contraception. Premature removal of the device is most often associated with heavy menstrual bleeding and pain, as with other long-term methods of contraception, and is most common in the youngest age group. When adequately counselled about the benign nature of oligo- or amenorrhoea, most women are very willing to accept life without menstruation. The risk of premature removal can be markedly diminished with good pre-insertion counselling, which also markedly increases user satisfaction. User satisfaction is strongly associated with the information given at the time of the levonorgestrel-releasing IUS insertion. Thus, the benefits of the levonorgestrel-releasing IUS make it a very suitable method of contraception for most women.

Influence of losigamone on the pharmacokinetics of a combined oral contraceptive in healthy female volunteers

OBJECTIVES

The influence of the new antiepileptic drug losigamone (CAS 112856-44-7/123783-52-8) on the pharmacokinetics of a combined oral contraceptive containing ethinylestradiol (CAS 57-63-6) and levonorgestrel (CAS 797-63-7) was investigated in 16 healthy women.

METHODS

This phase I study consisted of 3 periods with an uncontrolled first period and a double-blind, placebo-controlled, cross-over design in the second and third period. All subjects received a single dose of 200 mg losigamone (1 tablet) in period 1 (on day 14) as well as multiple doses of losigamone (3 tablets = 600 mg per day) or placebo for 15 days in periods 2 and 3. During all three periods an oral contraceptive containing 30 microg ethinylestradiol and 150 microg levonorgestrel was given. Single-dose pharmacokinetics was investigated on day 14 of period 1. Multiple-dose pharmacokinetic investigations were performed on day 15 of periods 2 and 3. The samples were assayed to derive pharmacokinetic data of ethinylestradiol and levonorgestrel. In addition, the concentrations of losigamone racemate (AO-33) and its enantiomers AO-242 and AO-294 were determined in these samples.

RESULTS

The mean values of the pharmacokinetic parameters AUC and Cmax of ethinylestradiol and levonorgestrel after multiple-dose treatment with losigamone or placebo were quite similar and met the criteria for bioequivalence. The 90% confidence intervals of the log-transformed ratios of the geometric means of the primary pharmacokinetic variables were included in the respective acceptance ranges of 80% to 125% (AUC) and 70% to 143% (Cmax).

CONCLUSIONS

The study demonstrated that multiple doses of losigamone did not influence the multiple dose kinetics of ethinylestradiol and levonorgestrel. The single- and multiple-dose kinetics of 200 mg losigamone and its enantiomeres did not differ from each other in a significant way. The combination of losigamone and the combined oral contraceptive was well tolerated and no serious adverse events occurred. It can be stated that the antiepileptic drug losigamone and the combined contraceptive do not interact each others metabolism.

Management of a perforated levonorgestrel-medicated intrauterine device--a pharmacokinetic study: case report

Intrauterine contraception is a widely used, highly effective method of birth control. Uterine perforation is a serious albeit rare complication with the use of an intrauterine device (IUD). Although uterine perforation by the levonorgestrel-releasing intrauterine system (LNG-IUS) has already been described, no plasma LNG concentrations in this setting were reported. Neither has the management of LNG-IUS been commented on to date. Two months after insertion of an LNG-IUS into a 33-year-old woman, it was noted to be in the peritoneal cavity. Laparoscopy for IUD removal was conducted 5 months after insertion. LNG and sex hormone-binding globulin plasma concentrations were measured prior to and following the laparoscopic removal of the IUD. Intra-peritoneal dislocated LNG-IUS resulted in plasma LNG levels 10 times higher (4.7 nmol/l) than the plasma level of LNG observed with LNG-IUS placed in utero. This high plasma LNG level suppresses ovulation. Therefore a misplaced LNG-IUS should be removed when pregnancy is desired.

Effect of concomitant hormone replacement therapy containing estradiol and levonorgestrel on the pharmacokinetics of selegiline

OBJECTIVE

The aim of this study was to investigate the effect of hormone-replacement therapy (HRT) on the pharmacokinetics of the selective monoamine oxidase B inhibitor selegiline and its primary metabolites desmethylselegiline and l-metamphetamine.

METHODS

In this randomised, double-blind, cross-over trial, 12 healthy female subjects received once daily for 10 days either HRT containing 2 mg estradiol valerate and 250 microg levonorgestrel or matched placebo. On day 10, they took a single 10-mg oral dose of selegiline. The serum concentrations of selegiline, desmethylselegiline and metamphetamine were measured for 32 h.

RESULTS

There was a 59% difference ( P=0.14) in the area under the serum concentration-time curve (AUC) of selegiline during the HRT compared with the placebo phase, but only a little or no concomitant reduction in the AUC of desmethylselegiline (-7%, P=0.071) or metamphetamine (2%, P=0.614) was observed. Maximum plasma concentration (C(max)) of selegiline was not changed, but a small, statistically significant, reduction in the C(max) of desmethylselegiline (-17%, P=0.03) was seen during the HRT phase. The C(max) of methamphetamine was slightly but not significantly reduced (-5%, P=0.06). The unchanged AUC ratios of desmethylselegiline/selegiline and metamphetamine/selegiline indicate that the primary metabolism of selegiline was not affected by HRT. All study treatments were well tolerated.

CONCLUSION

Unlike oral contraceptives, HRT is not likely to have clinically significant pharmacokinetic interaction with selegiline.

Levetiracetam does not alter the pharmacokinetics of an oral contraceptive in healthy women

PURPOSE

This study was designed to evaluate whether levetiracetam, a novel antiepileptic drug (AED), influences the pharmacokinetics of steroid oral contraceptives.

METHODS

During a run-in phase, 18 healthy female patients received an oral contraceptive containing ethinyl estradiol, 0.03 mg, and levonorgestrel, 0.15 mg, for the first 21 days of two consecutive menstrual cycles. In a subsequent double-blind, randomized, two-way crossover treatment phase, subjects received either levetiracetam, 500 mg, or placebo twice daily concomitant with the oral contraceptive. Plasma concentrations of ethinyl estradiol and levonorgestrel were measured on days 14 and 15 of the two treatment periods for the evaluation of the 24-h kinetic parameters, and an additional sample was collected on day 21 to determine the trough plasma concentrations. Serum progesterone and luteinizing hormone (LH) levels were determined on days 13, 14, 15, and 21 of each cycle of the treatment phase.

RESULTS

The plasma concentration-time curves and pharmacokinetic parameters of ethinyl estradiol and levonorgestrel were not statistically different during concomitant treatment with either levetiracetam or placebo. The ratios of the log-transformed geometric mean areas under the plasma concentration-time curves (AUCs), maximal (Cmax) and minimal (Cmin) plasma concentrations, and trough concentrations on day 21 (C21) ranged from 99.12 to 99.96% for ethinyl estradiol and from 97.13 to 99.41% for levonorgestrel. The 90% confidence intervals of these ratios were well within the 80 to 125% acceptance range for lack of interaction. Serum progesterone and LH concentrations were fairly constant during the run-in and treatment phases and remained markedly below their respective physiologic levels. Safety and menstrual-bleeding patterns were comparable during levetiracetam and placebo administration.

CONCLUSIONS

Levetiracetam does not affect the pharmacokinetics of an oral contraceptive containing ethinyl estradiol and levonorgestrel, and on the basis of serum progesterone and LH levels, it does not affect the contraceptive efficacy.

Pharmacokinetics of levonorgestrel 0.75 mg tablets

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.

Pharmacokinetic study of different dosing regimens of levonorgestrel for emergency contraception in healthy women

BACKGROUND

Levonorgestrel (LNG) is a commonly used progestin for emergency contraception; however, little is known about its pharmacokinetics and optimal dose for use.

METHODS

Serum levels of LNG and sex hormone-binding globulin (SHBG) were measured in five women who received three different regimens: A: 0.75 mg LNG twice with a 12 h interval; B: 0.75 mg twice with a 24 h interval; and C: 1.50 mg in a single dose, with a washout period of 28 days between each treatment. Blood samples were taken before pill intake and at 1, 2, 4, 8 and 12 h after each dose, every 12 h up to day 4 and every 24 h until day 10. LNG and SHBG were measured in all samples.

RESULTS

Maximum LNG concentrations were of approximately 27 nmol/l for treatments A and B, and close to 40 nmol/l for treatment C. The area under the curve was significantly higher for treatment C during the first 12 h, and significantly lower for treatment B during the first 24 h. After 48 h and up to 9 days from onset of treatment, serum LNG levels were similar in all three regimens. SHBG levels remained stable for 24 h, decreasing to 60% of the initial value from day 5 until day 10, with no difference between regimens.

CONCLUSIONS

The similarity of LNG serum levels obtained with one single dose of 1.5 mg or two doses of 0.75 mg with a 12 h interval justify a clinical comparison of these two regimes.

A pharmacokinetic study with a low-dose oral contraceptive containing 20 microg ethinylestradiol plus 100 microg levonorgestrel

This study investigated the pharmacokinetics of a dose-reduced oral contraceptive containing 20 microg ethinylestradiol (EE) + 100 microg levonorgestrel (LNG) in 18 young, healthy females. Serum levels of EE and LNG were determined after single and repeated daily oral administration over three treatment cycles, each consisting of 21 treatment days followed by a 7-day treatment-free period. Additionally, the time courses of sex hormone-binding globulin (SHBG), corticoid-binding globulin (CBG) and total and free testosterone serum levels were analyzed. Both active ingredients were rapidly absorbed and maximum concentrations in serum were reached between, on average, 1 and 2 h after single and multiple administrations, respectively. Concentrations of EE increased during repeated daily administration. An approximate two-fold accumulation was calculated based on the comparison of EE area under the curve (AUC) (0-24 h) values determined after the first and the last tablet administration within a treatment cycle. LNG serum concentrations also increased during repeated daily administration, reaching steady-state levels after about 11 days. Based on the comparison of AUC (0-24 h) values determined after the first and the last tablet administration, LNG accumulated approximately by a factor of 3 within a treatment cycle. Steady-state pharmacokinetics of LNG were similar at the end of the first and the third treatment cycles, indicating no further accumulation of LNG beyond a treatment cycle under long-term use of this combined oral contraceptive. The clearance and volume of distribution of LNG decreased and the terminal half-life increased after repeated daily administration, compared with single administration. These effects have also been reported for other LNG/EE combinations. SHBG serum concentrations increased during repeated daily intake by, on average, 1.5-1.6-fold, and for CBG, an average increase of 1.4-1.8-fold was found. Although free testosterone concentrations declined during repeated daily administration by about 40%, total testosterone remained relatively unchanged at a low level. In conclusion, the pharmacokinetics of EE and LNG determined in the present study were in good agreement with those previously reported for 30 microg EE + 150 microg LNG, taking the 33% dose reduction into account.