title: Kinetic studies of nitrofurazone photodegradation by multivariate curve resolution applied to UV-spectral data.
abstract: This work aims at describing the kinetic model of nitrofurazone photodegradation by a novel chemometric technique, hybrid hard-soft multivariate curve resolution (HS-MCR). The study was applied to UV-spectral data from the photolysis of nitrofurazone solutions at different concentrations and exposed under varying illuminance power. The HS-MCR method was able to elucidate the kinetics of the photodegradation process and to determine the rate constants, and estimating at the same time the pure spectra of the degradation products. Exposure to light of the drug gave a first rapid isomerization to the syn-form that in turn underwent degradation furnishing a mixture of yellow-red products. The photodegradation process could be explained with a kinetic model based on three consecutive first-order reactions (A>B, B>C and C>D). These results were confirmed by application of the MCR procedure to the analysis of the data obtained from HPLC-DAD analysis of the nitrofurazone samples at different reaction times. The kinetic model was observed to be dependent on experimental conditions. The samples at higher concentrations showed rate constants lower than the diluted samples, whereas an increase of the rate of all degradation processes was observed when the light power also increased. This work shows the power of the hybrid hard- and soft-multivariate curve resolution as a method to deeply study degradation processes of photolabile drugs.
authors.affiliation: Department of Pharmaceutical Sciences, University of Calabria, Via P Bucci, 87036 Rende, Cosenza, Italy. michele.deluca@unical.it
authors.forename: Michele
authors.initials: M
authors.lastname: De Luca
authors.forename: Sílvia
authors.initials: S
authors.lastname: Mas
authors.forename: Giuseppina
authors.initials: G
authors.lastname: Ioele
authors.forename: Filomena
authors.initials: F
authors.lastname: Oliverio
authors.forename: Gaetano
authors.initials: G
authors.lastname: Ragno
authors.forename: Romà
authors.initials: R
authors.lastname: Tauler
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry / Q000528:radiation effects*; D004355:Drug Stability; D007536:Isomerism; D007700:Kinetics; D016018:Least-Squares Analysis; D008027:Light; D008956:Models, Chemical; D015999:Multivariate Analysis; D009583:Nitrofurazone / Q000737:chemistry / Q000528:radiation effects*; D010782:Photolysis; D013056:Spectrophotometry, Ultraviolet; D013678:Technology, Pharmaceutical / Q000379:methods*
chemical_list: D000900:Anti-Bacterial Agents; D009583:Nitrofurazone