Comparison of plasma hormone changes using a "conventional" and a "paper" pill formulation of a low-dose oral contraceptive

The hormonal profile in women using combined monophasic oral contraceptive pills varies across the pill cycle: a temporal analysis of serum endogenous and exogenous hormones using liquid chromatography with tandem mass spectroscopy

Oral contraceptive pills, of all types, are used by approximately 151 million women worldwide; however, a clear understanding of the concentrations of endogenous and exogenous hormones across a 28-day combination monophasic oral contraceptive pill pack is not well described. In our study of 14 female participants taking various combination monophasic oral contraceptive pills, we found significant fluctuations in endogenous and exogenous hormone levels throughout the pill cycle. Our analysis revealed significantly greater levels of ethinyl estradiol on the 20th and 21st days of active pill ingestion, compared with days 1-2 (active) and days 27-28 (inactive pill ingestion). Conversely, estradiol concentrations decreased during active pill consumption, while progestin and progesterone levels remained stable. During the 7 days of inactive pill ingestion, estradiol levels rose sharply and were significantly higher at days 27-28 compared with the mid and late active phase time points, while ethinyl estradiol declined and progestin did not change. These findings challenge the previous assumption that endogenous and exogenous hormones are stable throughout the 28-day pill cycle.NEW & NOTEWORTHY The results from this study have wide-ranging implications for research and treatment in women's health including considerations in research design and interpretation for studies including women taking oral contraceptives, the potential for more precise and personalized methods of dosing to reduce unwanted side effects and adverse events, and the potential treatment of a variety of disorders ranging from musculoskeletal to neurological with exogenous hormones.

A sensitive direct radioimmunoassay for assessing D-norgestrel levels in human plasma

A direct radioimmunoassay was developed for assessing the levonorgestrel levels in human plasma without the need for heat, chromatographic or extraction pretreatment. D-norgestrel-3 (0-carboxymethyl)-oximino-BSA conjugate was used to raise antibodies having a low binding affinity towards other endogenous steroids. The rivanol-purified antiserum after dilution was used as the binding protein. The direct assay of levonorgestrel in human plasma was then compared to an extraction procedure. Lower intra-assay variability was shown by the direct assay when compared to the extraction method used at a sensitivity level of 0.15 nmol/L. The performance of the direct assay in quality control tests was more than favourable when compared with the extraction procedure. An examination of the effects of protein concentration on extraction efficiency was carried out together with an assessment of levonorgestrel levels in plasma in eight normal healthy women currently taking oral contraceptives and eight women who were not, at 0-24 h after the ingestion of 150 micrograms of D-NG and 30 micrograms of ethynyl oestradiol.

Fluctuations in quantitative features of intermediate cells in normal cervical smears during the menstrual cycle of ovulating women and contraceptive users

In this study we report on the variation in nuclear and cytoplasmic size of intermediate cells in normal cervical smears, in relationship to the week of the menstrual cycle and in relationship to the mode of contraception. A total of 18000 cells from 360 different women was studied. A significant difference in nuclear size of intermediate cells in smears from ovulating women not using contraception was found in comparison with intermediate cells in smears from women using contraceptive pills (ANOVA: F(1.312) = 4.98, p less than 0.02). Also a significant difference in the nuclear size of intermediate cells in smears from women using norgestrel- (or levonorgestrel)-containing formulas compared with lynestrenol-containing formulas was found (ANOVA: F(1.232) = 5.82, p less than 0.01). The influence of exogenous and endogenous hormones on cell populations in cervical smears is discussed. It is concluded that in studies on intermediate cells in cervical smears the contraceptive status of the women has to be taken into account.

Radioimmunoassay of plasma ethinylestradiol in the presence of circulating norethindrone

A reliable radioimmunoassay (RIA) for the measurement of ethinylestradiol (EE2) in plasma after the separation of norethindrone (NET) by column chromatography has been developed. The procedure involves diethyl ether extraction, followed by celite column partition chromatography to separate NET from EE2. An antiserum against ethinylestradiol-7-(3-thiopropionic acid)-bovine serum albumin conjugate was employed. Tritiated EE2 was used as the radioligand. The separation of bound from free 3H-EE2 was carried out with dextran-coated charcoal. This RIA procedure was used to measure plasma EE2 at specified time intervals in three women following oral administration of a tablet containing EE2 (0.12 mg) and NET (1.0 mg). The results show that EE2 is rapidly absorbed after oral administration. Peak concentrations of plasma EE2 were reached within 1.0 to 1.5 hours and then declined biphasically. The EE2 alpha phase half-life values in three subjects were 1.5, 2.8 and 3.8 hours. By comparison, the half-life values for the beta phase for the same three women were 6.2, 12.3 and 14.5 hours, respectively. Plasma samples were also analyzed for NET by RIA. The half-life values for the beta phase for EE2 and NET in the three subjects were similar.

An investigation of the pharmacokinetics of ethynylestradiol in women using radioimmunoassay

A radioimmunoassay for ethynylestradiol (EE) which is applicable to plasma samples obtained from women, who have taken a combination type oral contraceptive, has been developed and fully validated. Plasma concentration of EE rise to a peak of 128 pg/ml following the oral administration of 50 microgram EE. Following the intravenous administration of the same dose of EE, plasma concentrations of the steroid declined biexponentially, the two half-lives being 0.83 and 6.75 hours. Comparison of the results of the intravenous and oral administration of the steroid suggested that its oral bioavailability is 42%. Although EE thus has a lower bioavailability than norethindrone, the pharmacokinetics of the two steroids, as reflected by half-lives, plasma clearance and volume of distribution, are very similar. The occurrence of a secondary peak in plasma at around 12 hours after dosing gave strong evidence that EE undergoes enterohepatic circulation in women; an event that may have considerable clinical significance.

Use and acceptance of the "paper pill". A novel approach to oral contraception

A randomized, crossover study comparing the acceptance of and attitudes towards two dosage forms of the same oral contraceptive product - a paper presentation and the conventional tablet, was carried out in a network of rural and suburban research centers in the State of Durango, México. The results failed to show any significant advantage (in terms of acceptability or continuation) of the paper formulation. Although two-thirds of the participants indicated a preference for the conventional tablet, there was a high degree of acceptance of the paper formulation among new oral contraceptive acceptors.