Abstract An HPLC assay with fluorimetric detection of the arbutin metabolites hydroquinone glucuronide (2) and hydroquinone sulphate (6) in urine was developed and validated. Methylarbutin (4) and 6 were synthesised as reference substances. Compound 2 was prepared enzymatically from hydroquinone and uridine 5′-diphosphoglucuronic acid using the glucosyltransferase system of rat liver microsomes and enriched by two liquid-liquid ...