Different spectrophotometric and TLC-densitometric methods for determination of pyrazinamide in presence of its impurity

Publication date: Available online 15 March 2017 Source:Bulletin of Faculty of Pharmacy, Cairo University Author(s): Neven Magdy Habib, Nourudin Wagih Ali, Nada Sayed Abdelwhab, Maha Mohamed Abdelrahman In this search, three selective spectrophotometric and TLC-densitometric methods have been developed and validated for quantitative determination of Pyrazinamide (PYN) and its impurity, Pyrazine-2-carboxylic acid (PYA). The proposed methods are third derivative spectrophotometric (Method I), first derivative of ratio spectra spectrophotometric (Method II), mean centering of ratio spectra spectrophotometric (MCR) (Method III) and TLC-densitometric (Method IV). In method (I); 3D amplitudes at 276.2 and 274.6nm were measured and used for determination of PYN and PYA, respectively. In method (II); PYN was determined by measuring the 1DD peak amplitude at 225.8nm using 30µgmL−1 of PYA as a divisor; on the other hand PYA was determined by measuring this amplitude at 245.2nm using 18µgmL−1 of PYN as a divisor. For method (III); the amplitudes of the mean centered ratio spectra at 268.4 and 268.8nm were used for PYN and PYA, respectively. On the other hand, the forth method is TLC-densitometric method at which the chromatographic separation was achieved using silica gel 60F254 TLC plates and mixture of methylene chloride: methanol: ammonia solution (7:3:0.1, by volume) as a developing system followed by UV-scanning at 275nm. The proposed methods were successfully applied f...
Source: Bulletin of Faculty of Pharmacy, Cairo University - Category: Drugs & Pharmacology Source Type: research