New Visible Quantitative Spectrophotometric Determination of Zolpidem from Tablets. Regression Statistics Analysis

Zolpidem is an effective hypnotic and sedative drug that improves sleep in patients with insomnia. It is aimed for use in patients with significant difficulties initiating sleep. This drug decreases the sleep latency, increases the duration of sleep and decreases the number of awakenings during sleep in patients with temporary (transient) insomnia. The main goal of this research was to find and develop a new spectrophotometric method in Visible range for quantitative analysis of Zolpidem in tablets and to successfully analyze linearity and regression statistics parameters. Following the complete diazotization reaction of Zolpidem and the coupling of the formed diazonium salts with Beta-naphthol, an azo dye was quantitatively obtained. Through the quantitative analysis of the intense orange azo dye with a reddish tint obtained, the exact amount of pure Zolpidem was determined, which had a value of 9.677 milligrams. This obtained value corresponded to 96.77 percent pure Zolpidem content in pharmaceutical tablet. An important objective was to compare the final obtained result with the official pure Zolpidem amount established by the pharmaceutical manufacturer and to exactly quantify the relative percentage deviation of the practically obtained quantity from this reference value, in accordance with Romanian and European Pharmacopoeias. The result obtained 9.677 milligrams was close enough to the official reference value of 10 milligrams pure Zolpidem, in pharmaceutical. It was found that the relative percentage deviation was 3.2252 percent and it fell perfectly within the normal range of values 7.5 percent established by the Romanian and European Pharmacopoeias.

Keywords—hypnotic and sedative drug; new spectrophotometric method; relative percentage deviation, regression statistics parameters; pure Zolpidem amount.