Milk and plasma concentrations of the progestin ST-1435 in women treated parenterally with ST-1435

Pertti L.A. Lähteenmäki, Soledad Diaz, Patricia Miranda, Horacio Croxatto, Pekka Lähteenmäki

Research output: Contribution to journalArticlepeer-review

17 Citations (Scopus)

Abstract

A subcutaneous contraceptive capsule releasing progestin ST-1435 was used by 6 breast-feeding women. One to three paired milk and plasma samples were collected over a one-month period and the concentrations of ST-1435 were determined by radioimmunoassay. An improved and sensitive method for determination of ST-1435 in milk was developed. A column chromatographic purification of milk prior to radioimmunoassay decreased the blank and improved sensitivity. The average plasma concentration of ST-1435 was 62 ± 20 pg/ml (mean ± SD). The average milk concentration of ST-1435 was 38 pg/ml (ranging from 7 to 73 pg/ml), while the average milk to plasma ratio was 0.60 (ranging from 0.25 to 0.91). There was a significant correlation between ST-1435 concentrations in breast milk and plasma, indicating that the concentration in plasma is the major determinant for the amount of ST-1435 excreted into milk. Since studies with this drug have shown good contraceptive efficacy and low bioavailability after oral intake, ST-1435 is a good candidate for lactational contraception.

Original languageEnglish
Pages (from-to)555-562
Number of pages8
JournalContraception
Volume42
Issue number5
DOIs
Publication statusPublished - Nov 1990

ASJC Scopus subject areas

  • Reproductive Medicine
  • Obstetrics and Gynaecology

Fingerprint

Dive into the research topics of 'Milk and plasma concentrations of the progestin ST-1435 in women treated parenterally with ST-1435'. Together they form a unique fingerprint.

Cite this