[The validity of radioimmunologic determination of bioavailability of beta-escin in horse chestnut extracts].
The bioavailability under steady state conditions of a standard, slow-release horse chestnut seed extract (HCSE)-containing product was compared with that of an analogous, fast-release test preparation (Noricaven novo) in a prospective, randomised, double-blind study in a double cross-over design. The serum concentration of beta-escin (CAS 6805-41-0) was measured by radioimmunoassay. In addition, the biopharmaceutical properties of the HCSEs present in the products were investigated, the amount and composition of the active ingredient, escin, being analysed with a validated HPLC method. The pharmacokinetics of this study were compared with the corresponding data of a similar investigation carried out under analogous conditions concerning study design, analytical methods and reference preparation. Comparison of the similar studies revealed differences in characteristic pharmakokinetic values of beta-escin in terms of a shift of the concentration time curves as could be demonstrated for the reference product. The total amounts of escin in the two products investigated did not differ significantly. However, quantitative and qualitative differences were detected in the constituents of the two different extract preparations. It is concluded that the high specificity of the validated beta-escin radioimmunoassay leads to analytical imprecision due to the variable constituents of the extract preparations used. It is necessary to test whether this problem can be solved using an analytical approach, which is specific for each extract.
Schrödter
A
A
Institut für Klinische Pharmakologie des Klinikums, Johann Wolfgang von Goethe-Universität, Frankfurt/Main.
Loew
D
D
Schwankl
W
W
Rietbrock
N
N
D000328:Adult; D019540:Area Under Curve; D018592:Cross-Over Studies; D003692:Delayed-Action Preparations; D004311:Double-Blind Method; D004928:Escin / Q000008:administration & dosage / Q000493:pharmacokinetics*; D005260:Female; D006801:Humans; D008297:Male; D010936:Plant Extracts / Q000008:administration & dosage / Q000493:pharmacokinetics; D011446:Prospective Studies; D011863:Radioimmunoassay; D015203:Reproducibility of Results
D003692:Delayed-Action Preparations; D010936:Plant Extracts; D004928:Escin