Study of molecular complexation of glycyrrhizic acid with chloramphenicol by electrospray ionization mass spectrometry

CONTEXT: Glycyrrhizic acid (GA) is a triterpene glycoside representing the main active component of licorice root extract obtained from plants of the Glycyrrhiza glabra L. and widely used as a complex-forming agent for the synthesis of new transport forms of the well-known drugs. AIMS: For the first time, the complexation of GA with chloramphenicol antibiotic (ChlA) was investigated by electrospray ionization mass spectrometry (ESI MS). SUBJECTS AND METHODS: ESI MS was utilized in order to determine the composition and evaluate the stability of complexes of the GA and ChlA. The validation of the complex formation was confirmed by ultraviolet/visible and infrared (IR) spectroscopy. RESULTS: MS data confirmed the noncovalent interactions between chloramphenicol and GA. Formation of the host: guest complexes of GA and chloramphenicol with the ratio 1:1 and 2:1 were registered in the negative ion mode. Binding of GA and ChlA was accompanied by changes in absorbance and IR spectrum of ChlA indicating the complex formation of these compounds. CONCLUSIONS: The research results confirmed the considerable potential of ESI MS as a technique for simple and fast detection of formation of the complexes of GA and the well-known drugs.