Open AccessOral versus Vaginal Absorption in Oestradiol in Postmenopausal Women. Effects of Different Particles Sizes
Author(s) -
D. E. Englund,
Elof D. B. Johansson
Publication year - 1981
Publication title -
upsala journal of medical sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.808
H-Index - 41
eISSN - 2000-1967
pISSN - 0300-9734
DOI - 10.3109/03009738109179241
Subject(s) - bioavailability , absorption (acoustics) , medicine , particle size , pharmacokinetics , area under the curve , dose , endocrinology , postmenopausal women , gastrointestinal tract , pharmacology , chemistry , materials science , composite material
Crystalline oestradiol-17 beta is poorly absorbed from the gastrointestinal tract. Three different fractions and a standard fraction containing oestradiol- 17 beta of a known particle size and surface area, were administered orally, to postmenopausal women, to test if changes in particle size will influence the absorption. The bioavailability of each fraction was determined by measurements of peripheral plasma oestrogens. Two different dosages of the standard fraction were given vaginally to compare the bioavailability after oral and vaginal administration. The gastrointestinal absorption was dependent of the particle size of oestradiol. The smaller particle the more rapid and effective absorption as reflected by increasing area under the plasma concentration curve of oestrone and oestradiol. The smallest particle, however, resulted in a pronounced initial oestradiol peak. The coarser particles were more slowly absorbed with more even plasma oestrogen elevation for a sustained period of time. The vaginal absorption of oestradiol was more effective than the gastrointestinal. When the same amount of an equal preparation according to particle size, was given vaginally the maximal plasma concentration was almost 40 times higher than when given orally.