Development of high-performance thin-layer chromatography method for herbals identification in extemporaneous oral solution

Abstract

The preparation of extemporal medicines in store includes carrying out intrapharmacy quality control and stability studies. Since there is no single analytical method that ideally suited for all drugs, for each formulation depend on its composition and analytical goal, appropriate quality control methods should be developed. The object of analysis was pediatric oral solution with sedative action that contains Valerian tincture, Motherwort tincture, and sodium bromide.

The purpose of research was the development of simple, specific and reproducible methods of active herbal ingredients identification formulated into oral solution.

Materials and methods. The high-performance thin-layer chromatography (HPTLC) was used as the method for analysis. It was performed on 200 × 100 mm silica gel 60 F 254 HPTLC glass plates (Merck, Germany). Standard solutions and samples were applied onto the plate as bands 8.0 mm wide using spray-on technique with Automatic TLC sampler ATS 4; the development was made in saturated Automatic developing chamber ADC 2, temperature and the relative humidity were 23 °C and 33 % respectively; the derivatization was performed using Chromatogram Immersion Device; the documentation was conducted using Visualizer with visionCATS software (CAMAG, Switzerland).

As a result two HPTLC identification methods have been developed for valerenic acids that are specific for Valerian tincture and flavonoids that are specific for Motherwort tincture. Thus, the sample preparation has been developed, the optimal chromatographic conditions have been chosen, the acceptance criteria have been proposed, and the reference chromatograms have been shown. Valerenic acids of oral solution were determined in mobile phase: cyclohexane, ethyl acetate, acetic acid (60:38:2); the derivatization of plates was performed through dipping with Anisaldehyde-sulfuric acid reagent and heated to 100 °C for 3 min; documentation was performed after derivatization under white light and UV 366 nm. Flavonoids of oral solution were determined in mobile phase: ethylacetate, methyl ethyl ketone, formic acid, water (5:3:1:1); the derivatization of plates was performed through dipping with Natural Products/PEG reagents, heated to 100 °C for 3 min before dipping; documentation was performed after derivatization under UV 366 nm.

Conclusions. The developed methods can be used for identification of oral solution, and for stability study with the purpose of determination of its storage conditions and shelf-life.