Ruzu®herbal bitters and glibenclamide tablets: Dissolution and in vitro release kinetics studies

Abstract

Background: The concomitant intake of poly-herbal medicines with orthodox drugs raises huge concerns about herb-drug interactions and patient safety, especially as the  pharmacokinetic properties of these herbal medicines are not known.
Objectives: This study aimed to determine the effect of Ruzu® herbal bitters on the  issolution profile and release kinetics of glibenclamide (Daonil®) in pH simulated dissolution media in order to predict possible herb-drug interaction.
Method: The assay of glibenclamide was carried out as described in the British  pharmacopeia (2014). In vitro dissolution of glibenclamide tablets was studied alone and with Ruzu® herbal bitters in phosphate buffer pH 6.8 using USP dissolution apparatus II at 75 rpm. Analysis of glibenclamide was done using High Performance Liquid chromatography coupled with a UV detector. Dissolution data were analysed and percentage glibenclamide
released in the dissolution medium determined; dissolution data were compared using a model independent approach. Different mathematical models were adopted to explore the release kinetics.
Result: The glibenclamide tablets studied showed satisfactory drug content as per BP  specifications. Ruzu® herbal bitters caused a significant reduction in the amount of glibenclamide released in vitro at gastrointestinal pH 6.8 (P < 0.001). The release of glibenclamide alone and with Ruzu® herbal bitters showed Higuchi mathematical model
as their best fitting model.
Conclusion: Ruzu® Herbal Bitters significantly decreased the dissolution of glibenclamide tablets at gastrointestinal pH of 6.8. This could reflect on in vivo bioavailability performance with potential for causing sub-therapeutic levels of glibenclamide in vivo. Further studies are needed to assess herb-drug interaction in vivo.

Keywords: Glibenclamide; Ruzu herbal Bitters; Dissolution; Release Kinetics