Evaluation of compatibility of itraconazole with excipients used to develop vesicular colloidal carriers

Liposomes and niosomes are known to be efficient vehicles for localized and systemic delivery of particularly lipophilic drugs resulting in their improved bioavailability, targeted delivery, and fewer side effects. These systems consist of bilayered membrane structures comprising amphiphilic molecules like phosphatidylcholine (liposomes) and nonionic surfactants (niosomes). Itraconazole (ITZ) is a widely used insoluble antifungal agent, which is known to be poorly absorbed from available marketed dosage forms. For countering the bioavailability related problem of oral ITZ products, vesicular systems like liposomes and niosomes could provide a rational approach. Drug-excipient interaction is being considered as an essential first step in development of any drug delivery system nowadays. Therefore, the present work describes the evaluation of drug-excipient interactions of ITZ with selected excipients used for development of liposomes and niosomes. Analytical techniques like differential scanning calorimetry, Fourier transform infrared spectroscopy, optical microcopy, and X-ray powder diffraction analysis were utilized for assessing the drug-excipient interactions. Isothermal stress testing was also performed to quantitatively measure the percent change in initial drug content from ITZ-excipient blends kept under stress conditions. The excipients included phospholipids (Phospholipon 90G(A (R)), Phospholipon 90H(A (R))), surfactants (Span 40 and Span 60), vesicular membrane stabilizer (cholesterol), and a solubilizer (3-hydroxypropyl-betacyclodextrin).