title: Quantitative determination of zopiclone and its impurity by four different spectrophotometric methods.
abstract: Four simple, sensitive and selective spectrophotometric methods are presented for determination of Zopiclone (ZPC) and its impurity, one of its degradation products, namely; 2-amino-5-chloropyridine (ACP). Method A is a dual wavelength spectrophotometry; where two wavelengths (252 and 301 nm for ZPC, and 238 and 261 nm for ACP) were selected for each component in such a way that difference in absorbance is zero for the second one. Method B is isoabsorptive ratio method by combining the isoabsorptive point (259.8 nm) in the ratio spectrum using ACP as a divisor and the ratio difference for a single step determination of both components. Method C is third derivative (D(3)) spectrophotometric method which allows determination of both ZPC at 283.6 nm and ACP at 251.6 nm without interference of each other. Method D is based on measuring the peak amplitude of the first derivative of the ratio spectra (DD(1)) at 263.2 nm for ZPC and 252 nm for ACP. The suggested methods were validated according to ICH guidelines and can be applied for routine analysis in quality control laboratories. Statistical analysis of the results obtained from the proposed methods and those obtained from the reported method has been carried out revealing high accuracy and good precision.
authors.affiliation: Pharmaceutical Analytical Chemistry Department, Faculty of Pharmacy, Beni-Suef University, Alshaheed Shehata Ahmad Hegazy St., 62514 Beni-Suef, Egypt.
authors.forename: Maha M
authors.initials: MM
authors.lastname: Abdelrahman
authors.affiliation: Pharmaceutical Analytical Chemistry Department, Faculty of Pharmacy, Beni-Suef University, Alshaheed Shehata Ahmad Hegazy St., 62514 Beni-Suef, Egypt.
authors.forename: Ibrahim A
authors.initials: IA
authors.lastname: Naguib
authors.affiliation: Analytical Chemistry Department, Faculty of Pharmacy, Cairo University, Kasr El-Aini St., 11562 Cairo, Egypt.
authors.forename: Mohamed R
authors.initials: MR
authors.lastname: El Ghobashy
authors.affiliation: Department of Chemical Laboratories, Forensic Medicine Authority, Justice Ministry, 114 Bairam El Tounsy St., El Sayeda Zeinab, Cairo, Egypt. Electronic address: n.aboyazeed@yahoo.com.
authors.forename: Nesma A
authors.initials: NA
authors.lastname: Ali
mesh_terms: D053961:Azabicyclo Compounds / Q000032:analysis / Q000737:chemistry*; D002138:Calibration; D002851:Chromatography, High Pressure Liquid; D004340:Drug Contamination; D008027:Light; D057230:Limit of Detection; D010879:Piperazines / Q000032:analysis / Q000737:chemistry*; D011725:Pyridines / Q000032:analysis / Q000737:chemistry*; D015203:Reproducibility of Results; D013053:Spectrophotometry / Q000379:methods*; D013056:Spectrophotometry, Ultraviolet
chemical_list: D053961:Azabicyclo Compounds; D010879:Piperazines; D011725:Pyridines; C515050:zopiclone; C108972:2-amino-5-chloropyridine
keywords: 2-Amino-5-chloropyridine; Dual wavelength; First derivative of ratio spectra; Isoabsorptive ratio; Third derivative; Zopiclone