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Urinary Excretion and Metabolism of Arbutin after Oral Administration of Arctostaphylos uvae ursi Extract as Film‐Coated Tablets and Aqueous Solution in Healthy Humans
Author(s) -
Schindler Gemot,
Patzak Ulrich,
Brinkhaus Benno,
Nieciecki Alexander,
Wittig Jörg,
Krähmer Nils,
Glöckl Ingmar,
Veit Markus
Publication year - 2002
Publication title -
the journal of clinical pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.92
H-Index - 116
eISSN - 1552-4604
pISSN - 0091-2700
DOI - 10.1177/009127002401102740
Subject(s) - hydroquinone , arbutin , chemistry , urine , metabolite , bioavailability , glucuronide , chromatography , excretion , crossover study , urinary system , pharmacology , biochemistry , medicine , endocrinology , alternative medicine , pathology , placebo
Bearberry leaves and preparations made from them are traditionally used for urinary tract infections. The urinary excretion of arbutin metabolites was examined in a randomized crossover design in 16 healthy volunteers after the application of a single oral dose of bearberry leaves dry extract (BLDE). There were two groups of application using either film‐coated tablets (FCT) or aqueous solution (AS). The urine sample analysis was performed by a validated HPLC cool‐array method (hydroquinone) and a validated capillary electrophoresis method (hydroquinone‐glucuronide, hydroquinone‐sulfate). The total amounts of hydroquinone equivalents excreted in the urine from BLDE were similar in both groups. With FCT, 64.8% of the arbutin dose administered was excreted; with AS, 66.7% was excreted (p = 0.61). The maximum mean urinary concentration of hydroquinone equivalents was a little higher and peaked earlier in the AS group versus the FCT group, although this did not reach statistical significance (C ur max = 1.6893 μmol/ml vs. 1.1250 μmol/ml, p = 0.13; t max (t midpoint) = 360 h vs. 440 h P = 038). The relative bioavailability of FCT compared to AS was 103.3% for total hydroquinone equivalents. There was substantial intersubject variability. No significant differences between the two groups were found in the metabolite patterns detected (hydroquinone, hydroquinone‐glucuronide, and hydroquinone‐sulfate).