UV-Vis spectrophotometry for rapid and specific quantification of amphotericin B: analytical method validation for ex vivo and in vivo studies in the development of nanoemulsion-incorporated thermosensitive gel.

Amphotericin B (AmB) is the first-line drug used for the treatment of cryptococcal meningitis (CM). AmB has poor gastrointestinal permeability due to its large molecular weight. In addition, AmB in injectable form has the disadvantages of high systemic side effects and low bioavailability in the brain because it cannot cross the blood-brain barrier (BBB). Therefore, it is important to develop new drugs with a more optimized delivery system. The nose-to-brain drug delivery system offers many advantages such as high bioavailability in the brain as it does not need to cross the BBB. AmB was developed in nanoemulsion (NE) system which provides controlled release and to avoid nasal clearance system, it was combined with thermosensitive gel (TG). To support the formulation development process, analytical method validation was conducted for AmB in methanol (MeOH) solvent, release media, nasal mucosal tissue and brain tissue. It was conducted to measure the concentration of AmB in TG-NE, in vitro, ex vivo and in vivo studies. The developed method was then validated based on ICH guidelines. The results obtained showed that the linear coefficient was ≥ 0.9998. The LLOQ values in MeOH, PBS + 2% SLS, nasal mucosa tissue and brain tissue were 1.63 µg/mL, 1.99 µg/mL, 1.55 µg/mL, 1.62 µg/mL, respectively. The accuracy and precision of the developed analytical method were found to be precise without the influence of dilution. Therefore, the method was successfully applied to measure the amount of AmB in TG-NE. The validated method was reported to be successful for measuring the amount of AmB in gel preparations, in vitro, ex vivo and in vivo studies showing uniformity of drug content, release profile and pharmacokinetic profile.