Determination of the acidity constant of metronidazole by ultraviolet spectroscopy in the aqueous medium
Abstract
In this work, an acidity constant (pKa) was determined for the metronidazole protonated species by ultraviolet (UV) spectroscopy, the experimental value obtained was treated with the computer program (SQUAD) obtaining a value of
pKa = (2.522 ± 0.001) Therefore, at pH < 2.522, the cationic species (MTZH+) predominates and at pH > 2.522, the neutral species (MTZ) predominates. Likewise, the molar absorptivity coefficients for each species were obtained for the first time.
Downloads
References
Balderas-Hernández, P., Ramírez-Silva, M. T., Romero-Romo, M., Palomar-Pardavé, M., Roa-Morales. G., Barrera-Díaz, C., Rojas-Hernández, A., (2008). Experimental correlation between the pKa value of sulfonphthaleins with the nature of the substituents groups. Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 69(4), 1235-1245.
Bendesky, A., Menéndez, D., (2001). Metronidazol: una visión integral. Revista de la Facultad de Medicina, UNAM, 44(6), 255-259.
Dobiáš, L., Černá, M., Rössner, P., Šrám, R., (1994). Genotoxicity and carcinogenicity of metronidazole. Mutation Research Reviews in Genetic Toxicology, 317(3), 177-194.
Gallo, G. G., Pasqualucci, C. R., Radaelli, P., Lancini, G. C., (1964). The ionization constants of some imidazoles. The Journal of Organic Chemistry, 29 (4), 862-865.
Leggett, D. J. (1985). SQUAD. In: Computational methods for the determination of formation constants. D. J. Leggett (Ed), Springer, Boston, MA. pp. 159-220.
Pramar, Y. V., Mandal, T. K., Bostanian, L. A., Le, G., Morris, T. C., Graves, R. A., (2021). Physicochemical and microbiological stability of compounded metronidazole suspensions in PCCA SuspendIt. International Journal of Pharmaceutical Compounding, 25(2), 169-175.
Rojas-Hernández, A., Ramírez, M. T., Ibáñez, J. G., González, I., (1991). Relationship of multidimensional predominance-zone diagrams with multiconditional constants for complexation equilibria. Analytica Chimica Acta, 246 (2), 435-442.
Rojas-Hernández, A., Ramírez-Silva, M. T., Ibáñez, J. G., González, I., (1991). Construction of multicomponent Pourbaix diagrams using generalized species. Journal of the Electrochemical Society,138 (2), 365.
Rojas-Hernández, A., Ramírez-Silva, M. T., González, I., Ibáñez, J. G., (1992). Multi-dimensional predominance-zone diagrams for polynuclear chemical species. Analytica Chimica Acta, 259 (1), 95-104.
Rojas-Hernández, A., Ramírez, M. T., González, I., (1993a). Equilibria among condensed phases and a multi-component solution using the concept of generalized species: Part I. Systems with mixed complexes, Analytica Chimica Acta, 278(2), 321-333.
Rojas-Hernández, A., Ramírez, M. T., González, I., (1993b). Equilibria among condensed phases and a multi-component solution using the concept of generalized species: Part II. Systems with polynuclear species. Analytica Chimica Acta, 278 (2), 335-347.
Wade, L.G. Jr., Química Orgánica. (2010). Pearson, México.
Wagil, M., Maszkowska, J., Białk-Bielińska, A., Caban, M., Stepnowski, P., Kumirska, J., (2015). Determination of metronidazole residues in water, sediment and fish tissue samples. Chemosphere, 119, S28-S34.
Copyright (c) 2023 Josa Hayra Villanueva-Reynoso, Dafne Sarahia Guzmán-Hernández, María Teresa Ramírez-Silva, Jorge Juárez-Gómez, Alberto Rojas-Hernández
This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.
