Recognition and simultaneous determination of ofloxacin enantiomers by synchronization–1st derivative fluorescence spectroscopy

Under controlling pH 3, R-(+)- and S-(−)-ofloxacin (OFLX) enantiomers can be well recognized and resolved by the synchronization–1st derivative fluorescence spectroscopic techniques, and the interference from urine blank also can be eliminated. The linear dynamic ranges are 0.36–2.16 (R), 0.36–2.89 and 3.16–31.6 μg/ml (S), respectively, for determining OFLX in urine samples. The limits of detection are 0.36 μg/ml (R) and the recoveries of R-(+)- and S-(−)-OFLX in urine samples are 97–104%. Relative standard deviation is <6.6%. Pharmacokinetic study of OFLX and levofloxacin shows that R-(+)- and S-(−)-ofloxacin reach their peak concentration in urine samples after a healthy subject has taken tablets for ∼3 and 6 h, respectively. R-(+)-OFLX can be obviously detected in 5–6 h after a healthy subject has taken tablets, indicating the transformation of S-(−)- to R-(+)-OFLX enantiomer in human body (in vitro).