Preparation and cyclodextrin assisted dissolution rate enhancement of itraconazolium dinitrate salt

The poor solubility of itraconazole (ITR) results in its variable oral absorption and bioavailability and has also proven to be a major setback in developing an efficient oral delivery system. To improve its solubility and dissolution profile, itraconazolium dinitrate salt (ITRDNT) was prepared and characterized using various spectral and thermal techniques. The morphology of the salt was studied using optical and scanning electron microscopy (SEM). Broth microdilution assay demonstrated antifungal efficacy of ITRDNT similar to ITR against four different fungal strains namely, Asparagillus fumigatus, Microsporum canis, Microsporum gypsum and Trichophyton rubrum. The salt exhibited better solubility profile than ITR in water and a number of pharmaceutical solvents. Dissolution studies revealed the total amount of drug released from ITRDNT in 3 h was four times greater than that of ITR. To further improve dissolution characteristics, the physical mixtures of ITR and ITRDNT with two cyclodextrins, beta-cyclodextrin (beta-CD) and HP-beta-cyclodextrin (HP-beta-CD) were prepared and their molar ratios were optimized. It was observed that about 75% of drug was released in 30 min from 1:3 molar ratio of ITRDNT and HP-beta-CD physical mixture, which was distinctly higher than ITR commercial capsules (70%). Owing to its facile and economical preparation and substantially better in vitro release profile, the ITRDNT and its CD physical mixtures could be better and cost effective alternatives to ITR and commercial ITR capsules.