Amirah S. Al-Attas

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 0.15M 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 derivative spectrofluorimetric determination of zopiclone and its degradation product, 2-amino-5-chloropyridine, in pharmaceutical formulations with preliminary tool in biological fluids for clinical evidence of zopiclone intake

A simple, fast, sensitive and stability-indicating derivative spectrofluorimetric method is presented for the assay of zopiclone (ZOP), a drug with hypnotic effect, and its main degradation product and major contaminant, 2-amino-5-chloropyridine (ACP). The method is based on measuring the inherent fluorescence intensity of both drugs at λex=300nm in methanol, then differentiation using D1 (first derivative technique). The developed method was found to be rectilinear over a range of 0.2-4μg/mL of ZOP and 4-100ng/mL of ACP. The limits of detection were 0.05μg/mL of ZOP and 0.2ng/mL of ACP with the limit of quantitation of 0.17μg/mL of ZOP and 0.7ng/mL of ACP. The outcoming results of the proposed method were compared to those obtained by a reference method showing no significant statistical difference between them concerning precision and accuracy. Additionally, the developed method was applied for detecting ACP in spiked human urine and plasma specimens as a tool of clinical evidence of zopiclone intake that can be easily implemented in forensic laboratories. The proposed method was validated as per ICH guidelines.