A Quantitative Ultraviolet (UV) Spectrophotometric Analysis of ZOPICLONE as a Cyclopyrrolone Sedative Hypnotic Drug in Pharmaceutical Tablets

Zopiclone is a Cyclopyrrolone sedative hypnotic drug, which considerably increases the normal transmission of gamma-aminobutyric acid (GABA) in the Central Nervous System, via modulating GABA-A-type receptors. The aim of this research was to exactly find and quantify the amount of pure Zopiclone, as an active substance in tablets. Zopiclone as a pure active substance was dissolved in Dioxane p.a. as a solvent to obtain a standard solution, 1.2 µg / mL, which showed an absorption maximum in the Ultraviolet (UV) range A = 0.231 that has corresponded to ƛ = 282 nm. Prepared pure standard solution absorbances for the studied concentration range between 0.60 μg/mL and 16.80 μg/mL were read out at the maximum absorption wavelength λ. = 282 nm of Zopiclone solutions in Dioxane p.a. as a solvent. The amount of pure Zopiclone calculated on a pharmaceutical tablet was found to be 7.214322 mg, very close to the officially stated active substance content (7.5 mg). The average allowed percentage deviation value found was (+) 3.80904 %, below the maximum official value of ± 10% stated by the Romanian, European, and International Pharmacopoeias Rules. The spectrophotometric UV analysis method was subjected to the statistical validation procedure. Sandell Sensitivity, the interference test, stability of prepared standard solutions, system precision, method precision, and analysis accuracy were found within the normal range of values. The statistical analysis has revealed a very good linearity of the UV proposed method, in the standard concentration range from 0.60 μg / mL to 16.80 μg / mL. Linear regression coefficient R² = 0.9997386 and correlation coefficient R= 0.9998693; R² > 0.9990 and R > 0.9990 were located within the normal official range of values. Standard error of the linear regression was SE = 0.0027056, SE <<1. Detection Limit LOD = 0.2848 μg / mL and Quantitation Limit LQ = 0.9493 μg / mL were found to be within the normal range of values.