Solubility of meloxicam in aqueous binary mixtures of formamide, N-methylformamide and N,N-dimethylformamide: Determination, correlation, thermodynamics and preferential solvation

Solubility, Dissolution Thermodynamics and Preferential Solvation of Meloxicam in (Methanol + Water) Mixtures

“…As observed, all the solubility curves exhibit maximum meloxicam solubility in neat methanol. Because the solutes reach their maximum solubilities in solvent systems exhibiting the same polarity [31], it is expected that the meloxicam δ 3 value would be 29.6 MPa 1/2 as the methanol value is at 298.15 K. Nevertheless, this value is lower compared with the one reported (δ 3 = 32.1 MPa 1/2 ) [6][7][8], which was calculated by means of the Fedors' method [32]. As indicated earlier, these discrepancies could be attributed to a specific drug solvation processes by methanol or water, which are not considered in Fedors' calculations [19].…”

“…Because V 3 values are not available for meloxicam in {methanol (1) + water (2)} mixtures, this property was considered as the same of the pure drug as calculated based on the Fedors' method, i.e. 183.3 cm 3 •mol −1 [6][7][8]. G 1,3 and G 2,3 values shown in Table 8 are negative in all cases, indicating that meloxicam exhibits affinity for bpth methanol and water.…”

“…Moreover, its low aqueous solubility makes difficult the design of liquid medicines of this drug. For these reasons, several investigations have been performed in order to increase its aqueous equilibrium solubility, mainly based in the use of different cosolvents, as has recently been summarized [6][7][8].…”

Measurement and modelling of the solubility for ketoconazole in {acetonitrile + water} mixtures at T = (293.2 to 313.2) K

“…Las funciones termodinámicas de mezcla se calcularon de acuerdo con las ecuaciones (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14), (1-15) y (1-22), a partir de los valores de entalpía y entropía de solución para el proceso ideal, a la temperatura armónica media.…”

“…Resultado: el C.V. es menor al 2%, por lo que la prueba cumple con la especificación.▪ Repetibilidad del método: En este caso se realizó la medición tres veces consecutivas a tres muestras independientes de diferente concentración. Precisión intermedia: Se evaluó la concordancia relativa del método obtenida entre determinaciones independientes realizadas en el mismo instrumento, por diferentes analistas(2), en distintos días(3). La prueba se efectúo con soluciones de MLX en hidróxido de sodio 0,1 N de concentración 10 μg g −1 .…”