Simple and Accurate HPTLC-Densitometric Method for Quantification of Delafloxacin (A Novel Fluoroquinolone Antibiotic) in Plasma Samples: Application to Pharmacokinetic Study in Rats

Delafloxacin (DLX) is a recently-approved fluoroquinolone antibiotic, which is recommended for the treatment of acute bacterial skin and skin structure infections. A thorough literature survey revealed only a single published method for the estimation of DLX using UPLC-MS/MS technique in biological samples. There is no high-performance thin-layer chromatography (HPTLC) method has been reported for the estimation of DLX in dosage forms and/or biological samples. Therefore, a selective, sensitive, rapid and validated HPTLC-densitometry technique has been used for the estimation of DLX in human plasma for the first time. HPTLC quantification of DLX and internal standard (IS; gatifloxacin) was carried out on glass coated silica gel 60 F-254 HPTLC plates using the ternary mixture of ethyl acetate:methanol:ammonia solution 5:4:2 (%, v/v/v) as the mobile phase. Densitometric detection was done at 344 nm. The R-f values were recorded as 0.43 and 0.27 for the DLX and the IS, respectively. The linearity range of DLX was obtained as 16-400 ng/band. A simple protein precipitation method was used for the extraction of analyte from plasma using methanol. The proposed HPTLC technique was validated for linearity, accuracy, precision, and robustness. The proposed HPTLC technique was successfully utilized for the assessment of pharmacokinetic profile of DLX in rats after oral administration. After oral administration, the peak plasma concentration of DLX was obtained as 194.19 ng/ml in 1 h. The proposed HPTLC method could be applied in study of pharmacokinetic profile and therapeutic drug monitoring of DLX in clinical practice.