BMD-TLC — a useful separation technique for quantitative analysis of arbutin and hydroquinone in herbal drugs

A three-step, bivariant multiple-development TLC technique (BMD-TLC) was used in the quantitative analysis of arbutin and hydroquinone (aglycone of arbutin) in commercially available herbal drugs used in kidney disorders. The separation was carried out on TLC Si60 F254s plates at a distance of 10 cm. The first step was the separation of analyzed compounds from ballasts at a distance of 1 cm in methanol; the second step was the separation of arbutin at a distance of 5.5 cm in an ethyl acetate-methanol-water (77:13:10, υ/υ/υ) solvent mixture; and the third step was the separation of hydroquinone at a distance of 4.5 cm in n-heptane-ethyl acetate (1:1, υ/υ) solvent mixture. At each step, the ballast zones were cut away. The densitometric quantification of arbutin and hydroquinone was performed at 285 nm. The linearity, precision, repeatability, LOD, and LOQ were determined for the method. In addition, the influence of chromatogram scanning technique on the results of quantitative analysis was determined. It is pointed out that the optimized MD-TLC separation method can be used in the qualitative and quantitative analysis of arbutin and hydroquinone both in raw plant matrices and in herbal drugs.