An exploratory study on the association of lifestyle factors with serum etonogestrel concentrations among contraceptive implant users

PURPOSE

To explore how diet and exercise habits associate with serum etonogestrel concentrations among contraceptive implant users.

MATERIALS AND METHODS

We conducted a secondary analysis of healthy, reproductive-age women using etonogestrel implants. This study was registered on ClinicalTrials.gov, NCT03092037. We assessed diet and exercise habits with two validated surveys: Healthy Eating Vital Signs and the Stanford Brief Activity Survey. Participants previously had their serum etonogestrel concentrations measured using a validated liquid-chromatography mass-spectrometry assay. We then used linear modelling to test for associations between survey responses and serum etonogestrel concentrations.

RESULTS

Among 129 participants, diet and exercise habits had no significant associations with serum etonogestrel concentrations (p = 0.22-0.72), with inconsistent effects found for increased caloric intake and sedentary lifestyle.

CONCLUSION

This exploratory study found no significant effect of diet or exercise habits on steady-state pharmacokinetics among contraceptive implant users.

CLINICAL TRIAL REGISTRATION

Clinicaltrials.gov: NCT03092037.

The sexuological impact of hormonal contraceptives based on their route of administration

Evidence on the effects of hormonal contraceptives on female sexuality is conflicting. We enrolled 556 women, divided into six groups: two composed of subjects using a combined hormonal contraceptive (COC) containing 0.020 ("COC20") and 0.030 ("COC30") mg of ethynyl estradiol (EE), "natural", using COC containing 1.5 mg of estradiol (E₂), "ring", using a vaginal ring releasing each day 0.015 mg of EE + 0.120 of etonogestrel, "subcutaneous", using a progestin only subcutaneous contraceptive implant releasing etonogestrel and "controls", using no hormonal contraceptive methods. The subjects were required to answer to the McCoy female sexuality questionnaire and were subjected to a blood test for hormonal evaluation. An ultrasound evaluation of the dorsal clitoral artery was also performed. The higher McCoy sexological value were recorded in the subdermal group; significant differences were recorded among the groups in terms of hormone distribution, with the higher levels of androstenedione in subdermal and control groups. The ultrasound evaluation of dorsal clitoral artery shows a significative correlation between pulsatility and resistance indices and orgasm parameters of McCoy questionnaire. The recorded difference in the sexual and hormonal parameters among the studied hormonal contraceptives may guide toward the personalization of contraceptive choice.

Contraceptive vaginal ring effectiveness is maintained during 6 weeks of use: a prospective study of normal BMI and obese women

BACKGROUND

A single study shows that contraceptive vaginal ring (CVR) use for up to 35 days in women with a normal body mass index (BMI) maintains serum hormone levels sufficient to suppress ovulation. This study is intended to confirm those results and to evaluate prolonged CVR use up to 42 days in both normal BMI and obese women.

STUDY DESIGN

Twenty women with a normal BMI and 20 obese women enrolled in a prospective open label clinical study of ethinyl estradiol (EE) and etonogestrel (ENG) pharmacokinetics during six weeks of use of a single CVR. Participants underwent twice-weekly evaluations to determine serum hormone concentrations, ovarian follicle development, endometrial thickness and bleeding patterns.

RESULTS

Thirty-seven women completed follow-up including eighteen women with a normal BMI and nineteen obese women. EE and ENG concentrations remained in therapeutic range for all women. Follicular development and endometrial proliferation were minimal. By the sixth week, 30% of participants reported spotting or bleeding.

CONCLUSIONS

A single CVR used for 6 weeks demonstrates therapeutic serum levels of EE and ENG among women with normal and obese BMI. Women who forget to remove the CVR at day 21 may well have continued contraceptive protection during the next 3 weeks.

Pharmacokinetics and ovarian suppression during use of a contraceptive vaginal ring in normal-weight and obese women

OBJECTIVE

Many observational studies indicate higher oral contraceptive failure among obese women, but most clinical trials and physiologic studies do not support these differences. Limited data indicate higher failure rates among obese contraceptive patch users. Data regarding contraceptive vaginal ring performance in obese women are needed.

STUDY DESIGN

Twenty normal weight (body mass index [BMI] 19.0-24.9; median, 21.65) and 20 obese (BMI 30.0-39.9; median, 33.7) women enrolled in a prospective study of ethinyl estradiol (EE(2)) and etonorgestrel pharmacokinetics and of ovarian follicle development, endometrial thickness, and bleeding patterns, all measured biweekly during the second cycle of contraceptive vaginal ring use.

RESULTS

Thirty-seven women completed follow-up. Mean day 0-21 EE(2) concentrations were lower among obese vs normal weight women (15.0 vs 22.0 pg/mL, respectively, P = .004), whereas etonorgestrel concentrations were similar (1138 vs 1256 pg/mL, respectively, P = .39). Follicular development was minimal in both groups, with only 5 women achieving a maximum follicle diameter >13 mm at any time during 3 weeks follow-up (3 normal weight and 2 obese women); these women had serum progesterone levels <1.0. Obese women reported more bleeding or spotting than normal weight women (3.6 vs 1.4 days, respectively, P = .01).

CONCLUSION

Although obese women had lower EE(2) levels during contraceptive vaginal ring use, they had excellent suppression of ovarian follicle development, similar to normal weight women. This predicts that contraceptive vaginal ring effectiveness will be similar in women with a BMI up to 39.9. The lower serum EE(2) levels in the obese women may explain the greater reported bleeding or spotting days.

No effect of Implanon® on inflammatory cardiovascular parameters

OBJECTIVE

Recently, we found decreased levels of C-reactive protein (CRP) during use of the low-dosed contraceptive implant Implanon®. To further elucidate, whether this finding might be a sign for a lower inflammatory reaction and is associated with changes in levels of other cytokines, we investigated the effect of this implant on interleukin-6 (IL-6) and adiponectin. Plasma lipids and sex hormone levels have been shown to interact with the investigated parameters in vivo and in vitro. Therefore these parameters were measured as well.

DESIGN

Prospective case-control study.

SETTING

Family-planning centre, University hospital.

SUBJECTS

Thirty-six non-smoking women with regular cycles.

INTERVENTIONS

Blood samples for the measurements were taken in the early follicular phase of the cycle in both groups. A second sample was taken 12 weeks after Implanon insertion or in the controls during the early follicular phase of cycle 4.

RESULTS

Implanon did not cause significant changes in IL-6, adiponectin or lipoprotein (Lp)(a). At baseline, there was a significant positive correlation between IL-6 and CRP and a negative correlation between adiponectin and CRP.

CONCLUSION

We did not observe a negative impact of Implanon on risk markers for atherosclerotic disease such as IL-6, adiponectin, and Lp(a). These data are reassuring for clinicians who prescribe progestagen-only preparations as first choice contraceptives in females with cardiovascular risk factors.

[Simultaneous determination of gestodene, etonogestrel and ethinylestradiol in plasma by LC-MS/MS following derivatization]

To establish a sensitive and specific method for simultaneous determination of gestodene, etonogestrel and ethinylestradiol in plasma by LC-MS/MS, plasma samples were extracted and derivatized before injection. An ESI ion source was used and operated in the positive ion mode with multiple reaction monitoring (MRM). Norgestrel was chosen as internal standard and performed on a C18 (100 mm x 2.1 mm, 5 microm) column. The concentrations of gestodene, etonogestrel and ethinylestradiol were measured, using step-gradient mobile phase and step-gradient flow rate. The method was validated over the concentration range of 0.1-20 ng x mL(-1) for gestodene and etonogestrel and 0.01-2 ng x mL(-1) for ethinylestradiol, and showed excellent linearity. The intra- and inter-assay accuracy and precision were below 10.0% and recovery was 93.6%-110.9% over the three concentration levels evaluated. The method was applied in pharmacokinetic study of the compound gestodene patch and the compound etonogestrel patch in rabbits. The LC-MS/MS method was selective, accurate and sensitive, especially the LOQ were 100 pg x mL(-1) for gestodene and etonogestrel and 10 pg x mL(-1) for ethinylestradiol. The method was successfully applied in pharmacokinetic study for contraceptives.

The combined etonogestrel/ethinyl estradiol contraceptive vaginal ring

Many factors influence the effectiveness of contraceptive methods. Oral contraceptives are the second most popular contraceptive method after female sterilization in the US. A total of 25% of women do not use their oral contraceptives correctly; 30% of women do not use them consistently. Several new contraceptive methods with alternate routes of delivery and less frequent dosing are available. The combined etonogestrel/ethinyl estradiol contraceptive vaginal ring is marketed under the name of NuvaRing. This is the only contraceptive ring approved by the FDA. The administration of steroids by the vaginal route may offer many advantages. Because of less frequent dosing, self-administration, and possibly, an improved side effect profile, the ring has the potential to increase successful use.

Management and localization strategies for the nonpalpable Implanon rod

PURPOSE

The goal of this paper is to review the imaging methods required for localizing nonpalpable Implanontrade mark.

METHOD

Different localization methods for nonpalpable Implanon rods are summarized, and clinical guidance is provided as to how best to localize such implants.

RESULTS

In the great majority of cases, optimal visualization of the single-rod Implanon rod is obtained with ultrasound using a high-resolution linear array transducer (10-15 MHz). An implant located just under the skin, under the fascia muscularis or one located deep in the muscle can most often be localized with ultrasound. In rare cases where ultrasound does not definitively locate the implant, magnetic resonance imaging is usually the next best choice. Measurements of serum etonogestrel levels may be necessary to confirm the presence or absence of the implant when it cannot be visualized by either of the two imaging methods.

DISCUSSION

Close clinical coordination between women's health care providers and radiologists is required to minimize or prevent removal complications and to facilitate subsequent contraceptive management of the patient.

Comparison of uterine concentrations of ethinyl estradiol and etonogestrel after use of a contraceptive vaginal ring and an oral contraceptive

OBJECTIVE

To compare uterine tissue concentrations of ethinyl estradiol (EE) and etonogestrel (ENG) after one cycle of use of a contraceptive vaginal ring (NuvaRing; NV Organon, Oss, The Netherlands) or a combined oral contraceptive (COC).

DESIGN

Randomized, open-label, pharmacokinetic study.

SETTING

Obstetrics and gynecology unit.

PATIENT(S)

Eight premenopausal women about to undergo hysterectomy but otherwise healthy.

INTERVENTION(S)

One cycle (17-21 days) of NuvaRing or COC treatment that ended with surgical hysterectomy.

MAIN OUTCOME MEASURE(S)

Tissue concentrations of EE and ENG in uterine tissue samples taken from the upper myometrium and mid-myometrium, the cervical region, and the endometrium.

RESULT(S)

In both groups, concentrations of EE and ENG were similar in uterine tissue taken from the upper myometrium and mid-myometrium and the cervical region. However, compared with the COC group, concentrations of both hormones were markedly lower in tissue samples from the endometrium of women who had been treated with NuvaRing.

CONCLUSION(S)

Vaginal administration of hormones with NuvaRing did not produce elevated uterine concentrations of EE and ENG, compared with an oral contraceptive.

Absence of pharmacokinetic interactions of the combined contraceptive vaginal ring NuvaRing with oral amoxicillin or doxycycline in two randomised trials

BACKGROUND

Two pharmacokinetic studies were performed to investigate whether there is any interaction between etonogestrel or ethinylestradiol released from the combined contraceptive vaginal ring NuvaRing and concomitant treatment with orally administered amoxicillin or doxycycline.

METHODS

In one study, healthy women were randomised to receive either NuvaRing alone for 21 days or NuvaRing for 21 days plus amoxicillin on days 1-10. After a 7-day ring-free washout period, women were crossed over to the alternate regimen for a further 21-day treatment period. The other study used an identical design except that women received doxycycline instead of amoxicillin. The amoxicillin study measured serum etonogestrel and ethinylestradiol levels and area under the serum concentration-time curve (AUC) values over the initial 12 hours on days 1 (AUC(12)) and 10 (AUC(216-228)) and the whole of days 1-11 (AUC(240)) and 1-22 (AUC(504)). The doxycycline study measured AUC values over the initial 24 hours on days 1 (AUC(24)) and 10 (AUC(216-240)) and the whole of days 1-11 (AUC(240)) and 1-22 (AUC(504)).

RESULTS

No differences in etonogestrel or ethinylestradiol serum concentrations were observed between subjects using NuvaRing alone versus those receiving the ring plus either of the antibiotics. Calculation of etonogestrel and ethinylestradiol interaction/control ratios confirmed the absence of pharmacokinetic interactions.

CONCLUSION

The results from these studies demonstrate the absence of pharmacokinetic interactions between etonogestrel and ethinylestradiol released from NuvaRing and the oral antibiotics amoxicillin and doxycycline, suggesting that contraceptive efficacy would also be unaffected.

Depot testosterone with etonogestrel implants result in induction of azoospermia in all men for long-term contraception

BACKGROUND

Combined testosterone and progestogen preparations are a promising approach to male hormonal contraception. We investigated the effect of s.c. etonogestrel with depot testosterone on spermatogenesis in normal men over a period of 48 weeks.

METHODS

Fifteen healthy men received three s.c. 68 mg etonogestrel implants. Testosterone pellets (400 mg) were administered at 12 weekly intervals.

RESULTS

Nine men completed 48 weeks of treatment. Four subjects chose to discontinue after 6 months, one man withdrew from the study early for personal reasons and one was withdrawn due to illness. Sperm concentrations of <1 x 10(6)/ml were achieved in all men by 16 weeks of treatment. All men became azoospermic, although the time to achieve this varied from 8 to 28 weeks. Azoospermia was maintained in eight of the nine men treated for 48 weeks, one subject showing partial recovery from 40 weeks. Testosterone levels remained in the physiological range throughout. Treatment did not result in weight gain, change in body composition or decline in high-density lipoprotein cholesterol concentrations.

CONCLUSIONS

The combination of three etonogestrel implants with depot testosterone results in rapid and consistent suppression of spermatogenesis. This can be maintained for up to 1 year and may therefore be a suitable approach for a long-acting male hormonal contraceptive.

[Two patients with a non-palpable, subcutaneously implanted contraceptive]

Two women, 33 and 31 years of age, were referred to a surgeon for the removal of a previously implanted hormonal contraceptive after the general practitioner had attempted this without success. However, no foreign body could be detected in either patient by surgery, echography and MRI and by X-ray, echography and MRI, respectively. They were then referred to a gynaecologist. In the first patient, a low level of etonogestrel confirmed that there was no contraceptive in her body. Subcutaneous contraceptives are sometimes implanted incorrectly. If the rod is not palpable at the site of insertion, then the etonogestrel level should be determined first of all. If the hormone level indicates that a rod is indeed present, then echography or MRI may be considered to localise it before resorting to surgical exploration. Many problems can be prevented by proper implantation.

The combined contraceptive vaginal ring, NuvaRing®, and tampon co-usage

We investigated the effect of tampon co-usage on systemic exposure to etonogestrel (ENG) and ethinylestradiol (EE) from the combined contraceptive vaginal ring, NuvaRing. One cycle of ring use consists of 3 weeks of ring use followed by a 1-week ring-free period. Fourteen healthy women were randomized to use both NuvaRing and tampons (Kotex( regular) or NuvaRing alone for one cycle; participants then switched to the alternate treatment regimen for a second cycle of ring use. The first tampon was self-administered on day 8 of the interaction cycle; 4 tampons a day were used for 3 consecutive days. Tampon co-usage did not result in any changes in serum ENG or EE concentrations and is thus not expected to compromise the ring's contraceptive efficacy.

The effect of low-dose 3-keto-desogestrel added to a copper-releasing intrauterine contraceptive device on menstrual blood loss: a double-blind, dose-finding, placebo-controlled study

OBJECTIVE

We sought to establish the lowest dose of 3-keto-desogestrel, when added to a copper-releasing intrauterine contraceptive device, that is needed to reduce menstrual blood loss to a very low level and to treat (essential) menorrhagia successfully.

STUDY DESIGN

A double-blind group comparative study was designed in which 203 healthy women with or without menorrhagia were enrolled and randomized to four different Multiload Cu250 intrauterine contraceptive devices, releasing 0 (control), 1.5, 3, or 6 microg of 3-keto-desogestrel daily. Menstrual blood loss, hemoglobin, and serum ferritin levels were determined before and during treatment.

RESULTS

All 3-keto-desogestrel-copper intrauterine contraceptive devices reduced menstrual blood loss significantly, causing a reduction of up to 30 to 40 mL after 12 months of use. All women with essential menorrhagia were considered to have been successfully treated after 6 months of use. Serum ferritin levels rose with all three 3-keto-desogestrel-loaded devices.

CONCLUSION

A Multiload Cu250 intrauterine contraceptive device releasing 1.5 microg of 3-keto-desogestrel daily is able to reduce menstrual blood loss to a very low level and to replete body iron stores in women with or without menorrhagia. Higher doses have no superior effect.

Prodrug versus drug effects of 150 micrograms desogestrel or 3-keto-desogestrel in combination with 30 micrograms ethinylestradiol on hormonal parameters: relevance of the peak serum level of 3-keto-desogestrel

The pharmacokinetics and pharmacodynamics of 150 micrograms desogestrel (DG) or 150 micrograms 3-keto-desogestrel (KDG) in combination with 30 micrograms ethinylestradiol (EE) were compared in a cross-over study. While the EE levels as well as the area under the curve (AUC) of KDG did not differ, significantly higher peak levels of KDG were observed after intake of the KDG-containing formulation. As compared to the control cycle, LH and FSH were not reduced on day 3 of the first treatment cycle (3/I), but markedly suppressed on day 21 of the third cycle (21/III), the effects being more pronounced with the DG-containing pill. The serum levels of testosterone, free testosterone, androstenedione, androstanediol glucuronide, and dehydroepiandrosterone sulfate (DHEA-S) were significantly reduced already on day 3/I, while sex hormone-binding globulin (SHBG) was unchanged and corticosteroid-binding globulin (CBG) was increased. Thereafter, both SHBG and CBG rose markedly. The progressive decrease in DHEA-S correlated best with free testosterone and androstanediol glucuronide. The results indicate that the peak level of KDG is more important for the biological effectiveness than the AUC of KDG which appears to antagonize the suppressive action of EE on gonadotropin release. The rapid decrease in the androgen levels seems to be due to a direct inhibitory action of the pill on ovarian and adrenal steroid biosynthesis.

Serum distribution of two contraceptive progestins: 3-ketodesogestrel and gestodene

A cross-over study of two oral contraceptive formulations, containing 30 micrograms ethinylestradiol in combination with 150 micrograms desogestrel (Marvelon) or 75 micrograms gestodene (Femovan), has been performed to compare the serum distribution and pharmacokinetics of gestodene and the active metabolite of desogestrel, namely 3-ketodesogestrel. Serum concentrations of both sex hormone-binding globulin (SHBG) and corticosteroid-binding globulin (CBG) were also measured and were increased more than 3-fold and 2-fold, respectively, on day 21 of the treatment cycle, with no statistically significant difference between treatment groups. In addition, 35 days after ingestion of either oral contraceptive had ceased, the serum SHBG and CBG concentrations were similar to the pretreatment values. During treatment cycles, increased serum SHBG levels were associated with a redistribution of 3-ketodesogestrel and gestodene such that the non-protein-bound (NPB) and albumin-bound fractions were reduced in concert with an increase in the relative proportions bound to SHBG. The proportion of gestodene bound to SHBG was consistently higher than that observed for 3-ketodesogestrel, and this undoubtedly reflects the higher affinity of SHBG for gestodene (Kd = 1.2 nM at 37 degrees C) when compared to 3-ketodesogestrel (Kd = 4.7 nM at 37 degrees C). It also probably accounts, in part, for the much higher total serum levels of gestodene (8.58 nmol/L) when compared to 3-ketodesogestrel (2.37 nmol/L) during the treatment cycles. Consequently, the absolute amounts of NPB, non-SHBG-bound, and SHBG-bound gestodene are significantly higher than those measured for 3-ketodesogestrel. It is concluded that ethinylestradiol-induced increases in serum SHBG levels during treatment with Marvelon or Femovan, influenced the distribution and total amount of 3-ketodesogestrel and gestodene in serum, respectively, and that this, combined with the higher affinity of SHBG for gestodene, results in a greater amount of bioavailable gestodene compared to 3-ketodesogestrel, despite the smaller dose of gestodene administered.

Pharmacokinetics and protein binding of 3-ketodesogestrel and gestodene in the serum of women during 6 cycles of treatment with two low dose oral contraceptives

The serum concentrations of 3-ketodesogestrel (KDG) and gestodene have been measured in 30 and 31 women respectively who took low dose oral contraceptives containing 30 micrograms ethinylestradiol together with either 150 micrograms desogestrel or 75 micrograms gestodene for 6 months. On days 1, 10 and 21 of the first third and sixth treatment cycles blood samples were drawn at 0, 0.5, 1, 1.5, 2, 3, 4 and 24 h. KDG and gestodene levels were measured by radioimmunoassays and were evaluated for Cmax (peak serum concentration), tmax (time to Cmax), and AUC (area under the curve) to 4 and 24 h. The overall total gestodene concentrations were higher and the accumulation of the steroid throughout a cycle greater than that of KDG. For example, the AUC0-4 of gestodene increased in cycle 1 by a factor of 2.8 (day 10 vs. day 1) and 3.6 (day 21 vs. day 1) compared to 2.3 and 2.6 for KDG. The higher concentration of gestodene reflects a lower volume of distribution than KDG, and is consistent with gestodene binding to sex hormone binding globulin (SHBG) with a higher affinity than KDG. Concentrations of KDG and gestodene were higher on day 1 of cycles 3 and 6 than on day 1 of cycle 1. The serum concentrations of KDG and gestodene during multiple dosing cannot be predicted on the basis of single dose pharmacokinetics.

Release kinetics of 3-keto-desogestrel from contraceptive implants (Implanon) in dogs: comparison with in vitro data

Ethylene-vinyl acetate (EVA) polymeric contraceptive implants (Implanon) containing 3-keto-desogestrel have been prepared aiming at an in vitro initial release rate of 60 micrograms 3-keto-desogestrel/day. These implants are designed to have an intended life-time of 2 years. During a 3-year period, the release of these implants was studied in 4 dogs after subdermal insertion, using plasma clearance of 3-keto-desogestrel assessed after intravenous administration of 3-keto-desogestrel and steady state plasma levels of 3-keto-desogestrel. The mean plasma level of 3-keto-desogestrel decreased gradually during the first year of the study, viz. from 1.64 nmol/1 at 7 days after implantation to 0.69 nmol/l after one year. At the end of the second year, the level had decreased further to 0.45 nmol/l while after 3 years, the mean 3-keto-desogestrel plasma level was 0.42 nmol/l. The calculated mean daily release of 3-keto-desogestrel decreased during the first year from 70 micrograms/day to 30 micrograms/day. During the second and third year, the decrease in release rate was much less, viz. going from 30 micrograms/day to 28 micrograms/day and from 28 micrograms/day to 25 micrograms/day, respectively. This indicates a much more constant release during the second and third year of the study. The calculated cumulative amount of 3-keto-desogestrel released from the implant during the dog study was 34.0 mg. Based on the initial amount of 3-keto-desogestrel in the implant of 68.3 mg, the remaining amount in the implants at termination of the study should be approximately 34.3 mg. Actually, the mean remaining amount of 3-keto-desogestrel was 33.8 mg, which is in very close agreement with the calculated value. Implants from the same batch as used in the in vivo study were also analyzed for the in vitro release at regular times during the 3-year study period. After one year, the in vitro release rate was about 43 micrograms/day whereas this release rate was 33 and 27 micrograms/day after 2 and 3 years, respectively. Although the in vitro set-up constantly gave a somewhat higher release in comparison with the in vivo release, it is apparent that the in vitro procedure is valuable for prediction of the in vivo release characteristics of the implant. There were no indications for 3-keto-desogestrel accumulation at the implantation site. No local irritations were seen and the animals had no discomfort at all.(ABSTRACT TRUNCATED AT 400 WORDS)

Pharmacokinetics and serum protein binding of gestodene and 3-keto-desogestrel in women after single oral administration of two different contraceptive formulations

Two low-dose oral contraceptives, both containing the same dose of ethinyl estradiol (EE2, CAS 57-63-6) but different progestins--gestodene (CAS 60282-87-3) and desogestrel (CAS 54024-22-5), respectively--were administered to 18 women in a single dose, cross-over study. The serum concentrations of gestodene (GEST, one of the components of Femovan) and 3-keto-desogestrel (KDG) have been measured by specific radioimmuno-assays and the pharmacokinetics of both progestins were assessed. The serum protein binding of both compounds was also investigated and although the free fraction was the same for GEST and KDG, the distribution with respect to the binding proteins albumin and sex hormone binding globulin (SHBG) was slightly different. GEST was mainly bound to SHBG, while KDG was predominantly bound to albumin. Maximum concentrations of GEST were observed after 0.7 +/- 0.2 h and amounted to 4.9 +/- 2.4 ng/ml. A biphasic pattern of disposition was observed, with half lives of 0.13 +/- 0.06 h and 14.6 +/- 4.2 h, respectively. The AUC was 32.9 +/- 18.3 ng.ml-1.h. For KDG, maximum serum levels of 1.7 +/- 0.8 ng/ml were observed 1.5 +/- 0.8 h post administration. Drug levels declined with half-lives of 0.5 +/- 0.2 h and 17.0 +/- 9.3 h, respectively, and the AUC was 15.2 +/- 10.9 ng.ml-1.h.

Pharmacokinetics and serum protein binding of 3-keto-desogestrel in women during three cycles of treatment with a low-dose combination oral contraceptive

The serum concentrations of 3-keto-desogestrel have been measured in 43 women who took a low-dose oral contraceptive containing 30 micrograms ethinyl estradiol (CAS 57-63-6) together with 150 micrograms desogestrel (CAS 54024-22-5) for a period of 3 months. Basic pharmacokinetic parameters, like Cmax, tmax and AUC, as well as the serum protein binding of 3-keto-desogestrel were determined on days 1, 10 and 21 of the first and the third treatment cycle, respectively. During cycle one, Cmax, AUC(0-4h) and AUC(0-24h) values on day 1 were 1.9 +/- 0.7 ng/ml, 3.9 +/- 1.3 ng.ml-1.h and 12.4 +/- 5.7 ng.ml-1.h, respectively. These values increased to 4.7 +/- 2.0 ng/ml, 12.1 +/- 5.6 ng.ml-1.h and 47.3 +/- 26.0 ng.ml-1.h on day 21. Within cycle 3, a similar, although less steep increase was observed for these parameters and there was practically no difference in the values of corresponding parameters on day 21 of both cycles. Throughout treatment, there was a redistribution of 3-keto-desogestrel with respect to the binding proteins albumin and sex hormone binding globulin (SHBG). During cycle 1, the free fraction decreased from 1.8% on day 1 to 1.1% on day 21, and the SHBG-bound fraction increased at the same time from 40% to 62%, mainly at the expense of the albumin-bound fraction. During cycle 3, there were only minor changes as compared to cycle one. The observed changes in the serum protein binding were related to an increase in SHBG levels during the treatment period.

Serum concentrations of ethinylestradiol, 3-keto-desogestrel, SHBG, CBG and gonadotropins during treatment with a biphasic oral contraceptive containing desogestrel

During a cross-over study, the pharmacokinetics of ethinylestradiol (EE) and 3-keto-desogestrel (KDG) were investigated on days 7 and 22 of one cycle of treatment with two biphasic formulations containing 50 micrograms EE (7 tablets) and 50 micrograms EE + 125 micrograms desogestrel (DG) (15 tablets) (50/50 EE) or 40 micrograms EE + 25 micrograms DG (7 tablets) and 30 micrograms EE + 125 micrograms DG (15 tablets) (40/30 EE). Peak serum levels and areas under the curve of EE increased significantly by 50% between days 7 and 22 of those taking 50/50 EE, while during treatment with 40/30 EE, no difference was found between days 7 and 22. Both formulations caused identical KDG levels on day 22. There were only slight differences in the effects of both preparations on sex-hormone-binding globulin (SHBG; +150 to +160%) and on corticosteroid-binding globulin (CBG; +130 to +150%) on day 7. On day 22, the changes were more pronounced with 50/50 EE (SHBG, +310%; CBG, +240%) than with 40/30 EE (SHBG, +250%; CBG, +180%). On day 22 after discontinuation of treatment, the SHBG and CBG levels were still significantly above the control values. Using both formulations, LH and FSH levels were significantly suppressed on day 22, while on day 7 no significant reduction was observed. The rise in the EE levels between days 7 and 22 of 50/50 EE intake and the time course of the EE concentrations during treatment with 40/30 EE appear to be due to an inhibition of hepatic metabolism by the contraceptive steroids, as EE is nearly exclusively bound to albumin which does not change.