Adulteration of locally manufactured herbal medicinal preparations for diabetes mellitus with metformin and glibenclamide on the Ugandan market

Abstract

Background: Adulteration of herbal antidiabetic products has been reported all over the globe. Studies conducted in Hong Kong showed that Glibenclamide and Metformin were commonly use adulterants detected in the products on market. Severe adverse events have also been reported following use of adulterated herbal products. Purpose: To detect and quantify metformin and glibenclamide in locally manufactured antidiabetic herbal preparations sold in Kampala, Uganda Methods: A cross-sectional study was conducted to document the locally produced herbal antidiabetic products. Products were obtained from the 5 divisions of Kampala going to herbal drug shops, pharmacies and local markets in the different sub-counties. Key parameters documented include included label quality, directions to use, indication claims and NDA notification status. The documented products were then prepared and screened using the TLC technique to rapidly detect presence of metformin and glibenclamide. The detection was based on the retention factors of the peaks obtained from the samples in comparison to the peaks of the Metformin and Glibenclamide standards. The positive products were analyzed using the HPLC technique to quantify the metformin and glibenclamide present. Calibration curves were generated from the peak area versus concentration data of the serial dilutions of the prepared standards curves. Results: Eighteen locally made herbal antidiabetic products sold in Kampala were examined and documented. They were mostly powders which are meant to be taken as a tablespoonful of powder in warm water twice daily. Two of the eighteen had good labels having all the basic requirements as stipulated by the NDA guidelines. Only one of the products was NDA notified. Three of the eighteen products were found to be adulterated with synthetic antihyperglycemics; metformin and glibenclamide. The adulterated products contained approximately 0.11 mg of glibenclamide, 6.14 mg and 20.7 mg of metformin for every 1 gram of the product Conclusion: Three of the eighteen documented products were adulterated with metformin and glibenclamide. There is need for more product registration and notification with the NDA to ensure better monitoring and regulation of product quality and safe use of these locally made herbal antidiabetic products.