Spektrofluorimetrijsko određivanje ciklopiroks olamina prevođenjem u ternarni kompleks s Tb(III) i EDTA

A highly sensitive and selective spectrofluorimetric method was developed for the determination of ciclopirox olamine in raw material and in dosage forms. The proposed method is based on the formation of a ternary complex with Tb(III) in the presence of ethylenediaminetetraacetic acid. It was found that this complex manifests intense fluorescence at λem 489 and 545 nm with excitation at 295 nm. Different experimental parameters affecting the fluorescence intensity of the complex were carefully studied and incorporated into the procedure. Under the described conditions, the method is applicable over the concentration range of 30150 and 1070 ng mL-1 with minimum detectability of 6.7 and 0.9 ng mL-1 at λem 489 and 545 nm, respectively. The mean percentage recovery at λem 489 and λem 545 nm ranged between 98.7 and 100.2 for the pure substance, solution, and cream. Relative error of 0.10.4% and RSD up to 0.9% were estimated at λem 489 and 545 nm. A proposal of the reaction pathway is given.Razvijena je vrlo osjetljiva i selektivna spektrofluorimetrijska metoda za određivanje antimikotika ciklopiroks olamina, kao čiste supstancije i u ljekovitim oblicima. Metoda se temelji na stvaranju kompleksa s Tb(III) u prisutnosti etilendiamintetraoctene kiseline. Nakon ekscitacije pri 295 nm taj kompleks intenzivno fluorescira pri λem 489 i 545 nm. Proučavani su različiti eksperimentalni parametri koji utječu na intenzitet fluorescencije kompleksa. Za opisane uvjete metoda se može primijeniti u koncentracijskom području 30150 i 10 70 ng mL-1. Minimalna koncentracija koja se može odrediti je 6,7, odnosno 0,9 ng mL-1 na λem 489, odnosno 545 nm. Analitički povrat pri λem 489 i λem 545 nm iznosio je 98,7100,2% za čistu supstanciju, otopinu i kremu. Relativna pogreška metode je 0,10,4%, a relativna standardna devijacija 0,9%. Predložena je jednažba kemijske reakcije

Spektrofluorimetrijsko određivanje ciklopiroks olamina prevođenjem u ternarni kompleks s Tb(III) i EDTA

A highly sensitive and selective spectrofluorimetric method was developed for the determination of ciclopirox olamine in raw material and in dosage forms. The proposed method is based on the formation of a ternary complex with Tb(III) in the presence of ethylenediaminetetraacetic acid. It was found that this complex manifests intense fluorescence at λem 489 and 545 nm with excitation at 295 nm. Different experimental parameters affecting the fluorescence intensity of the complex were carefully studied and incorporated into the procedure. Under the described conditions, the method is applicable over the concentration range of 30150 and 1070 ng mL-1 with minimum detectability of 6.7 and 0.9 ng mL-1 at λem 489 and 545 nm, respectively. The mean percentage recovery at λem 489 and λem 545 nm ranged between 98.7 and 100.2 for the pure substance, solution, and cream. Relative error of 0.10.4% and RSD up to 0.9% were estimated at λem 489 and 545 nm. A proposal of the reaction pathway is given.Razvijena je vrlo osjetljiva i selektivna spektrofluorimetrijska metoda za određivanje antimikotika ciklopiroks olamina, kao čiste supstancije i u ljekovitim oblicima. Metoda se temelji na stvaranju kompleksa s Tb(III) u prisutnosti etilendiamintetraoctene kiseline. Nakon ekscitacije pri 295 nm taj kompleks intenzivno fluorescira pri λem 489 i 545 nm. Proučavani su različiti eksperimentalni parametri koji utječu na intenzitet fluorescencije kompleksa. Za opisane uvjete metoda se može primijeniti u koncentracijskom području 30150 i 10 70 ng mL-1. Minimalna koncentracija koja se može odrediti je 6,7, odnosno 0,9 ng mL-1 na λem 489, odnosno 545 nm. Analitički povrat pri λem 489 i λem 545 nm iznosio je 98,7100,2% za čistu supstanciju, otopinu i kremu. Relativna pogreška metode je 0,10,4%, a relativna standardna devijacija 0,9%. Predložena je jednažba kemijske reakcije

Derivative spectrophotometric analysis of benzophenone (as an impurity) in phenytoin

Three simple and rapid spectrophotometric methods were developed for detection and trace determination of benzophenone (the main impurity) in phenytoin bulk powder and pharmaceutical formulations. The first method, zero-crossing first derivative spectrophotometry, depends on measuring the first derivative trough values at 257.6 nm for benzophenone. The second method, zero-crossing third derivative spectrophotometry, depends on measuring the third derivative peak values at 263.2 nm. The third method, ratio first derivative spectrophotometry, depends on measuring the peak amplitudes of the first derivative of the ratio spectra (the spectra of benzophenone divided by the spectrum of 5.0 μg/mL phenytoin solution) at 272 nm. The calibration graphs were linear over the range of 1-10 μg/mL. The detection limits of the first and the third derivative methods were found to be 0.04 μg/mL and 0.11 μg/mL and the quantitation limits were 0.13 μg/mL and 0.34 μg/mL, respectively, while for the ratio derivative method, the detection limit was 0.06 μg/mL and the quantitation limit was 0.18 μg/mL. The proposed methods were applied successfully to the assay of the studied drug in phenytoin bulk powder and certain pharmaceutical preparations. The results were statistically compared to those obtained using a polarographic method and were found to be in good agreement