Acta Pharm. 64 (2014) 15-28

 

full paper

Original research paper

 

Spectrofluorimetric determination of gemifloxacin mesylate and linezolid in pharmaceutical formulations: Application of quinone-based fluorophores and enhanced native fluorescence

BAHIA ABBAS MOUSSA, MARIANNE ALPHONSE MAHROUSE, MAHMOUD ALI HASSAN and MICHAEL GAMAL FAWZY

mariannealphonse@yahoo.com

1 Pharmaceutical Chemistry Department, Faculty of Pharmacy, Cairo University, Kasr El-Aini St., Cairo11562, Egypt

2 Pharmaceutical Medicinal Chemistry Department, Faculty of Pharmacy, Egyptian Russian University, BadrCity, Cairo, 11829, Egypt

Accepted October 20, 2013

 

Quinone-based fluorophores and enhanced native fluorescence techniques were applied for a fast quantitative analysis of gemifloxacin mesylate (GEM) and linezolid (LIN) in pharmaceutical formulations. For this purpose, three sensitive, accurate and precise spectrofluorimetric methods were developed. GEM, as an n-electron donor, reacts with 7,7,8,8-tetracyanoquinodimethane (method A) and 2,5-dichloro-3,6-dihydroxy-p-benzoquinone (method B) as π-electron acceptors, forming charge transfer complexes that exhibit high fluorescence intensity at 441 and 390 nm upon excitation at 260 and 339 nm, respectively. Method C depends on measurement of enhanced native fluorescence of LIN in phosphate buffer (pH 5) at 380 nm upon excitation at 260 nm. Experimental factors affecting the fluorescence intensity were optimized. Linearity was obtained over concentration ranges 50–500, 10–60 and 20–400 ng mL−1 for methods A, B and C, respectively. The developed methods were validated and successfully applied for determination of the cited drugs in tablets.

 

Keywords: gemifloxacin mesylate, linezolid, 7,7,8,8-tetracyanoquinodimethane,2,5-dichloro-3,6-dihydroxy-p-benzoquinone,fluorimetry, charge transfer complex