A comparison of the high-performance liquid chromatography and RIA measurement of medroxyprogesterone acetate

Mould, G P; Read, J. I.; Edwards, D.; Bye, Alan

doi:10.1016/0731-7085(89)80072-x

Cited by 4 publications

(2 citation statements)

References 7 publications

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“…There is no trend showing that only older studies (20 to 40 years old) report higher C max values or only more recent studies (up to 20 years old) report lower C max values. It is not possible to deduce from these data ( 51 , 75 – 77 ) whether differences in C max values reported for DMPA-IM between studies are due to differences in detection methodology, number of injections, time of measurement after injection, or intrinsic factors of the study group such as interindividual differences in metabolism, lactation, body weight, size, or ethnicity. Furthermore, within one study, serum concentrations at both peak and plateau can vary between individuals by as much as 10-fold or 38-fold ( 45 , 47 ).…”

Section: Contraceptives: Actions Types and Serum Concentrationsmentioning

confidence: 99%

Hormonal Contraception and HIV-1 Acquisition: Biological Mechanisms

2018

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Access to effective affordable contraception is critical for individual and public health. A wide range of hormonal contraceptives (HCs), which differ in composition, concentration of the progestin component, frequency of dosage, and method of administration, is currently available globally. However, the options are rather limited in settings with restricted economic resources that frequently overlap with areas of high HIV-1 prevalence. The predominant contraceptive used in sub-Saharan Africa is the progestin-only three-monthly injectable depot medroxyprogesterone acetate. Determination of whether HCs affect HIV-1 acquisition has been hampered by behavioral differences potentially confounding clinical observational data. Meta-analysis of these studies shows a significant association between depot medroxyprogesterone acetate use and increased risk of HIV-1 acquisition, raising important concerns. No association was found for combined oral contraceptives containing levonorgestrel, nor for the two-monthly injectable contraceptive norethisterone enanthate, although data for norethisterone enanthate are limited. Susceptibility to HIV-1 and other sexually transmitted infections may, however, be dependent on the type of progestin present in the formulation. Several underlying biological mechanisms that may mediate the effect of HCs on HIV-1 and other sexually transmitted infection acquisition have been identified in clinical, animal, and ex vivo studies. A substantial gap exists in the translation of basic research into clinical practice and public health policy. To bridge this gap, we review the current knowledge of underlying mechanisms and biological effects of commonly used progestins. The review sheds light on issues critical for an informed choice of progestins for the identification of safe, effective, acceptable, and affordable contraceptive methods.

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Section: Contraceptives: Actions Types and Serum Concentrationsmentioning

confidence: 99%

Hormonal Contraception and HIV-1 Acquisition: Biological Mechanisms

2018

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“…Ether extraction and enzymic hydrolysis techniques indicate that the majority of the drug in vivo is present as a glucuronide conjugate (Mathrubutham & Fotherby 1981). Recent and 130 more specific chromatographic techniques which are able to distinguish the parent molecule from its metabolites showed concentrations 5 to 10 times lower than with RIA, confirming that a large proportion of the drug is present as metabolites (Mould et al 1988). It is not known if these metabolites are biologically active.…”

Section: Mpa Assaysmentioning

confidence: 92%

Clinical Significance of Differences in Bioavailability of Medroxyprogesterone Acetate Preparations

Stockdale

Rostom²

1989

Clinical Pharmacokinetics

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Synthetic progestational agents first became widely available in the early 1960s and were investigated for use in patients with hormoneresponsive tumours, i.e. breast, kidney, uterine and prostate cancer. A range of different preparations was available, but their clinical use was limited by side effects including nausea and vomiting, masculinisation, Cushingoid effects and liver damage (Stoll 1967). An early study (Stoll 1967) of 6 orally active agents, including medroxyprogesterone acetate (MPA), concluded that all were active in breast cancer and that resistance to one agent did not necessarily imply resistance to others. However, response rates were disappointing, ranging from 16 to 22%, and over the ensuing years the use of medroxyprogesterone acetate was confined mainly to endometrial and kidney cancers. High-Dose MPA in Carcinoma o/the BreastInterest in medroxyprogesterone acetate in carcinoma of the breast was rekindled by the work of Pannuti and colleagues, who investigated its maximum tolerated intramuscular dose;and reported greatly increased objective response rates of 44% with intramuscular doses of 1500mg daily for 30 days (Pannuti et al. 1978). Although the initial studies were troubled by a high incidence of sterile abscess formation at the injection site, investigators were impressed by a feeling of well being associated with increased appetite and weight gain due to the drug, which were thought to be of benefit to the patient. Prompt improvement of bone pain was also noted for many patients. These results implied a dose-response effect for medroxyprogesterone acetate, which became accepted on the basis of the historical results (Ganzina 1979). It might thus be assumed that differing bioavailability of medroxyprogesterone acetate preparations could be of significance. When radioimmunoassay (RIA) techniques became available to measure serum medroxyprogesterone acetate concentrations, attempts were made to rationalise dosage schedules and elucidate the pharmacokinetics of the drug.

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Hormones, Sex Hormones

Gunnet

Dixon

2000

Kirk-Othmer Encyclopedia of Chemical Technology

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Progestins are a class of steroids named for their role in maintaining pregnancy. Naturally occurring progestins, such as progesterone, are 21‐carbon steroids having the basic pregnane structure. Synthetic progestins are derived from four structural groups; ie, 5α‐prenanes, 5α‐androstanes, estranes, and gonanes. They are produced by chemical and microbial degradation of naturally occurring steroids and by total synthesis. Structure–activity relationships of progestins have been explored using computer‐aided techniques. The principal use of progestins is in contraception, prescribed alone or in combination with estrogens, where they act primarily to prevent uncontrolled estrogen stimulation of the uterine endometrium. Progestins have other uses based on their antiestrogenic effects. They are known to cause a conformational change in receptors. When bound to an agonist, progestin receptors act as transcription factors, altering the rate of expression of various genes. New antiprogestins with improved receptor specificity are becoming available and may eventually be used in some of the same therapeutic areas as progestin agonists.

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A comparison of the high-performance liquid chromatography and RIA measurement of medroxyprogesterone acetate

Cited by 4 publications

References 7 publications

Hormonal Contraception and HIV-1 Acquisition: Biological Mechanisms

Hormonal Contraception and HIV-1 Acquisition: Biological Mechanisms

Clinical Significance of Differences in Bioavailability of Medroxyprogesterone Acetate Preparations

Hormones, Sex Hormones

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