Physico-chemical characterization and dissolution properties of nifluminic acid-cyclodextrin-PVP ternary systems

In view of the poor aqueous solubility of nifluminic acid (NIF), the aim of this article was to improve its solubility and dissolution rate through the preparation of formulations based on hydroxypropyl beta-cyclodextrin (HP beta CD) and polyvinylpyrrolidone K25 (PVP K25), a combination of carriers which has been advantageously used for a similar purpose with various hydrophobic drugs. Ternary systems of NIF, HP beta CD, and PVP K25 were prepared in different drug to CD to PVP ratios by physical mixing, kneading, microwave irradiation, and co-evaporation. Differential scanning calorimetry, thermogravimetric analysis, hot stage microscopy, Fourier transform infrared spectroscopy, and X-ray powder diffractometry were used to investigate the resulting solid-state interactions. The results showed that the solid state of the drug in the amorphous or crystalline ternary combinations influenced both the solubility and the dissolution rate of NIF.