Quantifying Ocular Besifloxacin with LC–MS–MS

A new liquid chromatography tandem mass spectrometry (LC-MS-MS) method has been developed to study besifloxacin, which is used to treat bacterial conjunctivitis.¹ Besifloxacin, along with other fluoroquinolones, is used to treat a wide range of ocular infections. However, the overuse of the fluoroquinolone class of antibiotics puts them at high risk of bacteria developing resistance to them.

Besifloxacin, developed specifically for ophthalmic use, displays potent efficiency against a wide range of Gram-positive and Gram-negative ocular pathogens, including multi-resistant strains. This complex mode of action and rapid distribution within ocular tissues theoretically reduces the risk of resistance making besifloxacin important pharmaceutically.

Two chromatographic methods were previously developed to study besifloxacin; however, both the chiral high performance liquid chromatography (HPLC) and HPLC with UV detection methods were insufficient according to the Chinese authors and did not meet the desired sensitivity, speed, and throughput in bio-sample analysis.

The new method developed for quantification of besifloxacin in ocular and plasma tissues used LC-MS-MS to reach the desired analytical requirements.

Tissues were obtained from rabbits and analyzed using this new method. The lower limit of quantification for besioflaxin was 0.103 ng/mL for plasma and 2.06 ng/mL for other ocular tissues with good accuracy, precision, and a short run time of 3.0 min. This was across single and multiple topical applications. 

According to the authors, this method was rapid and reproducible and therefore suitable for the pharmacokinetic study of besifloxacin. - L.B.

References

1. X.F Gu et al., J. Pharm. Biom. Anal. 117, 37-46 (2016).