Development and Validation of Miroestrol Analysis in Kwao Keur Khao Capsules Using UPLC Technique

Abstract

The main active compound of Pueraria spp. (kwao kkruea khao in Thai) is miroestrol, whose content has been found to be highly variable in nature. Thus, it is necessary to control the quality of raw materials and products to ensure their efficacy and consumers’ safety. This study aimed to develop and validate a UPLC method for analysis of miroestrol in kwao khruea khao capsules. Each of the samples was extracted with ethanol and the extract obtained was cleaned up with a Sep-Pak si SPE cartridge. Miroestrol in the extract was separated on a BEH c18 (100 5 2.1 mm, 1.7 μm) column with a mobile phase composed of water and acetonitrile at a flow rate of 0.5 mL/min at detection wavelength of 214 nm. The developed method was validated according to the ICH guidelines. For miroestrol at the concentration range of 0.001–0.1 mg/g, its linearity was observed with a correlation coefficient (r) of 0.9999. The %RSDs of miroestrol content for repeatability and intermediate precision were 2.06% and 3.02%, respectively. The recovery rate of this method was 102–105%; and the limits of detection and quantification of miroestrol were 0.5 and 1 μg/g, respectively. The developed method was used for analysis of capsule products, and results showed that nine out of 22 samples contained miroestrol at concentrations of 1.40–15.68 μg/g. In conclusion, this method is suitable and can be properly used for miroestrol determination in kwao khruea khao capsules.