Simultaneous assessment of ciprofloxacin and dexamethasone in ocular tear fluid by LC-MS/MS: Application to a pharmacokinetic study in rabbits

Abstract

• Robust and fast method for estimation of CFX and DEX in rabbit tears, aqueous humor, and corneal biofluids using LC-MS/MS were established. • The developed method was successfully validated as per USFDA guidelines. • Simple precipitation technique used for extraction. • The method was applied for the pharmacokinetic study of marketed CFX and DEX eye drop solution in NZ Albino Rabbits. • PK/PD indices and simulation were estimated. A simple and fast LC-MS/MS method was developed and validated for simultaneous quantitation of ciprofloxacin (CIP) and dexamethasone (DEX) in tear fluid and partially validated for aqueous humor and cornea. Samples were cleaned- up by single-step precipitation using methanol as an anti-solvent. Agilent SB C 18 column with a total run time of 4.5 min was used for chromatographic separation utilizing isocratic mode. MS detection was carried out by a triple quadrupole tandem mass spectrometer (TQMS) in the multiple reaction monitoring (MRM) modes utilizing a positive electrospray ionization (+ESI). The developed method showed a wide analytical range (CIP: 0.7812 – 200 ng/mL and DEX: 1.875- 240 ng/mL) with good linearity (r 2 > 0.998) and acceptable accuracy and precision. It also showed excellent recoveries (> 85% for all analytes) and a negligible matrix effect. Finally, this method was successfully applied to the pharmacokinetic (PK) profile of clinically used eye drop solution of CIP and DEX (CiploxD) in preclinical rabbit tears, suggesting its suitability for PK profiling and PK-based dosage regimen design against various pathogens.