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ACTIVITY AND BIOAVAILABILITY OF TOPICAL STEROIDS. IN VIVO / IN VITRO CORRELATIONS FOR THE VASOCONSTRICTOR TEST
Author(s) -
Barry B. W.,
Woodfordf R.
Publication year - 1978
Publication title -
journal of clinical pharmacy and therapeutics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.622
H-Index - 73
eISSN - 1365-2710
pISSN - 0269-4727
DOI - 10.1111/j.1365-2710.1978.tb00102.x
Subject(s) - bioavailability , bioequivalence , in vivo , vasoconstriction , chemistry , pharmacology , pharmacokinetics , steroid , in vitro , chromatography , bioassay , biochemistry , medicine , biology , microbiology and biotechnology , hormone , genetics
Summary The vasoconstrictor assay for topical steroids has been modified and extended so that it may be used to screen for activity and to determine bioavailability. The precision, sensitivity and reproducibility were good for a bioassay. Hydro‐philic preparations containing steroid in solution exhibited rank‐order relationships between applied concentration and vasoconstriction (Cartesian, semilog, log‐probability and log‐logistic coordinates). Similar response curves obtained using applied concentration in vivo or amount of steroid released in vitro suggested that vasoconstriction data reflected the amount of steroid penetrating to the capillaries. Pharmacokinetics were non‐linear. The assay as developed exceeds the FDA Bioequivalence Requirements and In Vivo Bioavailability Procedures.