Solubility Advantage of Pyrazine-2-carboxamide: Application of Alternative Solvents on the Way to the Future Pharmaceutical Development

Abstract

The solubility of an antitubercular drug in alternative solvents can offer a potential application in pharmaceutical processing. Solid−liquid equilibrium (SLE) measurements have been made using a dynamic (synthetic) method. The melting point, the enthalpy of fusion, temperature of the solid−solid phase transition, and corresponding enthalpy of pyrazine-2-carboxamide were obtained using differential scanning calorimetry (DSC). The solubility of pyrazine-2carboxamide in bis(trifluoromethylsulfonyl)amide ionic liquids is at least 1 order of magnitude lower than that in the studied trifluoromethanesulfonate ionic liquid. 1-Decyl-3-methylimidazolium trifluoromethanesulfonate ionic liquid was found to be the best solvent for a carboxamide drug. The solid−liquid phase equilibria were described using six different correlation equations which revealed a relatively good description with an acceptable standard deviation temperature range. Nonvolatile ionic liquids, due to their safer aspects, can compete with other potentially flammable chemicals that are routinely used in the pharmaceutical development, given the data presented for the pyrazine derivative. Bis(trifluoromethylsulfonyl)amide and trifluoromethanesulfonate based ionic liquids showed sufficient solubilities toward a drug; thus, it makes them suitable for the future pharmaceutical processing.

Solubility of a New Cardioactive Prototype Drug in Ionic Liquids

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Solubility and thermodynamic functions of deferasirox in different solvents

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New quantum chemistry-based descriptors for better prediction of melting point and viscosity of ionic liquids

“…), were gathered from the literature. [28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46] A multivariate correlation with inputs based on quantum chemistry descriptors, and the output of the experimental values of melting point, Tm, was performed utilizing Eureqa software, a data analysis tool developed by Nutonian, Inc. Out of the 37 experimental melting point data, 17 (i.e. 45% of the data points) were chosen as part of the validation set (depicted in green in Figure 2), which were not used in the process of the model development.…”