Separation, Identification, and Quantitative Analysis of the Epimers of Cefaclor by TLC-Densitometry

The epimers of cefaclor have been separated, identified, and analyzed quantitatively by TLC. The stationary phase was silica gel 60 F(254), modified with beta-cyclodextrin, and the mobile phase was chloroform-ethyl acetate-glacial acetic acid-water 4:4:4:1 (v/v). Chromatograms were developed at 5 degrees C, dried at room temperature, and analyzed densitometrically at 274 nm, the wavelength of maximum absorption. Under these conditions good separation of the epimers was achieved (R(F) 0.26 and 0.33). UV and (1)H NMR spectra were used to identify the epimers. The method is characterized by high sensitivity (LOD 0.24 and 0.27 mu g per band for the epimers at R(F) 0.26 and 0.33, respectively, LOQ of 0.74 and 0.83 mu g per band, respectively, and high accuracy (recovery between 100.03 and 100.81%) and precision (RSD from 0.67 to 1.73%).