Simultaneous determination of zopiclone and its degradation product and main impurity (2-amino-5-chloropyridine) by micellar liquid chromatography with time-programmed fluorescence detection: Preliminary investigation for biological monitoring

A simple and reliable HPLC method was developed and validated for the simultaneous determination of the hypnotic drug, zopiclone (ZPC) and its degradation product and main impurity, 2-amino-5-chloropyridine (ACP). The analyses were carried out on BDS Hypersil phenyl column (4.6 mm × 250 mm, 5 μm particle size) using micellar mobile phase consisting of 0.15 M SDS, 10% n-propanol, 0.3% triethylamine, and 0.02 M orthophosphoric acid (pH 3.5) with timed programmable fluorescence detection. The proposed method was found to be rectilinear over the concentration ranges of 0.5–10.0 μg/mL for ZPC and 2.5–50 ng/mL for ACP. Moreover, the method was applied for the determination of ZPC in commercial tablets with mean percentage recovery of 99.06 ± 1.49. The results of the proposed method were statistically compared with those obtained by the comparison method revealing no significance differences in the performance of the two methods regarding accuracy and precision. Furthermore, the proposed method was applied for the detection and determination of ACP in human urine as a marker for ZPC intake.

► First MLC method for determination of zopiclone and 2-amino-5-chloropyridine (ACP).
► The method is highly sensitive for ACP down to 2.5 ng/mL.
► The method was applied for purity testing of zopiclone within the BP limit.
► The method was extended to determine ACP in urine as a marker for zopiclone intake.
► No pretreatment steps are required due to the solubilizing ability of the micelles.