Quantitation of zopiclone and desmethylzopiclone in human plasma by high-performance liquid chromatography using fluorescence detection

Development and Validation of a Reversed-Phase HPLC Method for the Estimation of Zolpidem in Bulk Drug and Tablets

In the present study an isocratic reversed-phase high-performance liquid chromatography method was developed for the estimation of zolpidem in bulk drug and pharmaceutical dosage forms. The quantification was carried out on C18columns. A mixture of acetonitrile-ammonium acetate (pH=8.0, 0.02 M) (60 : 40 v/v) was used as the mobile phase, at flow rate of 1.0 mL/min and the determination wavelength at 245 nm. The retention time of zolpidem was found to be 3–5 min. The validation of the proposed method was carried out for specificity, linearity, accuracy, precision, limit of detection, limit of quantification, and robustness. The linear dynamic range was from 2.5 to 30 μg mL−1. Regression equation was found to bey=0.1416x+0.0183with correlation coefficientr=0.9996. The percentage recovery obtained for zolpidem was greater than 96.5%. Limit of quantification and limit of detection were found to be 2.5 μg mL−1and 0.83 μg mL−1, respectively. The developed method can be used for routine quality control analysis of zolpidem in tablet formulations.

Methods for the analysis of nonbenzodiazepine hypnotic drugs in biological matrices

Zopiclone, zolpidem and zaleplon (Z-drugs) are nonbenzodiazepine hypnotic drugs that are used for the treatment of insomnia. These drugs were developed with the intent to overcome some disadvantages of benzodiazepines, such as dependence and next day sedation. In general, the nonbenzodiazepine hypnotic drugs are administered in oral doses daily and are widely biotransformed in the body. A large number of analytical methods based on chromatographic and electrophoretic techniques for the quantification of Z-drugs and their metabolites in biological matrices have been reported. In this review, the bioanalytical methods for Z-drugs were reviewed with the focus placed on sample preparation procedures and the separation techniques used. Furthermore, as these drugs are also reported as drugs of abuse or in drug-facilitated crime, screening methods that simultaneously cover these drugs and also other drugs of abuse were included in this review.