Study of the stability of the biologically active compound N-[2-[4-oxo-3(4H)-quinazolinyl]propionyl]-guanidine using electrophoresis and mass spectrometry

Abstract

At the Scientific Centre of Innovative Medicines of Volgograd State Medical University, a number of pyrimidine derivatives of guanidine were designed and synthesised to study them as promising inhibitors of sodium-hydrogen exchanger isoform 1 (NHE-1), which can reduce tissue damage during ischemia. N-[2-[4-oxo-3(4H)-quinazolinyl]propionyl]-guanidine (VMA-13-15) proved to be the most pharmacologically valuable compound. When preparing regulatory documentation for a new medicine, one of the quality criteria is the amount of related impurities. They can be technological impurities and degradation products of the active substance. The aim of the research was to study the stability of the biologically active compound N-[2-[4-[4-oxo-3(4H)-quinazolinyl]propionyl]-guanidine. Anticipated degradation products were determined by stress testing, using capillary electrophoresis and mass spectroscopy. The study of the molecule of VMA-13-15 and the use of computer technologies allowed us to predict possible degradation processes. Among them, the most likely to occur is the hydrolysis reaction during thermostating of the solution of the studied compound in an alkaline medium. In silico optimisation of the geometry of the studied structures was carried out by the MM+ molecular mechanics method using HyperChem 8.0.9. The final spatial optimisation of the geometry of the modelled molecules was carried out by the density functional theory method ub3lyp with 6-311G** basis sets. The resulting vibrational analysis of thermodynamic characteristics was carried out in Orca, which allowed us to obtain enthalpy and entropy values for the studied compounds. By capillary electrophoresis, the degradation products of an aqueous solution of the studied substance were analysed by stress tests. They were used to study the effect of thermal treatment on VMA-13-15 in the presence of 0.1 M hydrochloric acid solution and 0.1 M sodium hydroxide solution. We found that the alkaline environment had the greatest effect on the stability of N-[2-[4-oxo-3(4H)-quinazolinyl]propionyl]-guanidine. It was consistent with the results of the computational experiment. We studied the mass spectrum of the degradation product detected during thermostatic treatment in alkaline medium. Based on its molar mass and release time, it was confirmed that the impurity on the chromatograms of VMA-13-15 is unsubstituted quinazolin-4(3H)-one, the initial product of the synthesis