Abstract
A simple, sensitive, and selective ultra-performance liquid chromatographic (UPLC) method with quadrupole-time of flight-mass spectrometric (Q-TOF-MS/MS) detection was developed for the determination of moxifloxacin (moxi) in rabbit aqueous humor. After a simple protein-precipitation by acetonitrile, the post-treatment samples were separated on a UPLC Bridged Ethyl Hybrid (BEH) C-18 column with 0.1% formic acid in water as a mobile phase and analyzed in positive ion mode. The method developed was validated in rabbit aqueous humor with a daily working range of 0.1-200 ng/mL with correlation coefficient, r(2) > 0.999 and a sensitivity of 0.12 ng/mL as limit of quantification. The method proved to be accurate (recovery, 96.0-99.3%), precise (%RSD, <= 0.71%), and specific and was applied to evaluate the moxifloxacin loaded nanoplexes (moxi-NPX) as vehicles for ocular drug delivery. Moxi-NPX (4037 +/- 45.9 ng/mL hr) provided approximately five-fold increase in the relative ocular bioavailability compared with moxi solution (806.5 +/- 32.5 ng/mL hr). In conclusion, moxi-NPX increases ocular bioavailability of moxi, prolongs its residence time in the eye, and are efficient ocular drug delivery vehicles.
Supplemental Materials are available for this article. Go to the publisher's online edition of Journal of Liquid Chromatography & Related Technologies to view the free supplemental file.