Investigation of Thermodynamic Equilibria of Vitamin C in Various Solvents Via Experimental Determination and Model Correlation

Abstract

Vitamin C plays an essential role in pharmaceutical industry. In general, the solubility of this vitamin in different environments is an important factor for drug development processes. Indeed, solid-liquid equilibrium (SLE) determination of the interested compound in various solvents needs high-precision determination which, however, frequently consumes a lot of time and labor work. In this study, we have developed a simple approach that allows detecting quickly solubility and other important thermodynamic data of dissolution processes. In fact, this approach bases on a combination of the polythermal SLE experimental-determination and the modified Apelblat model. Besides water as a single solvent, different alcohols will be used in this work. For all studied media, dissolution processes are found as endothemic with positive values of enthalpy of dissolution. Furthermore, different alkyl groups have shown influence on the solubility of this compound. Indeed, vitamin C tends to dissolve in water stronger than in ethanol and 2-propanol that relates to polarity properties and hydrogen bonding formation. The results in this contribution gain a good agreement comparing to the reported values from the literature.