Rapid identification and quantification of carbohydrate excipients in Gardeniae Fructus formula granules by ATR-FTIR spectroscopy

Abstract

Formula granule is a traditional Chinese medicine (TCM) preparation usually made from the decoction of a single herbal medicinal by spray drying. It is easy to make a TCM formula decoction by dissolving multiple formula granules in hot water, instead of boiling the herbal medicinals in water for hours. The flexibility and convenience make formula granules more and more popular in TCM clinical applications. However, the efficacy and safety of commercial formula granules often suffer from the excessive addition of carbohydrate excipients. In this research, Fourier transform infrared (FTIR) spectroscopy is used for the simple and rapid detection of carbohydrate excipients in formula granules of Gardeniae Fructus (GF). Using the attenuated total reflection (ATR) accessory, formula granules can be measured directly free of pretreatments or chemical reagents. Lactose and sucrose in simulated GF granules can be identified by the characteristic peaks in the second derivative spectra when the weight concentration of the excipient is 10%. Dextrin, which is the most common excipient in commercial formula granules, in simulated GF granules can be quantified by the partial least squares calibration model when the weight concentration of dextrin is above 5%. The excessive addition of dextrin is found in some commercial GF formula granules. This research shows the potential of ATR-FTIR spectroscopy in the rapid, green, and low-cost detection of carbohydrate excipients for the quality control of GF formula granules and analogues.