Structure elucidation and spectroscopic analysis of photodegradants of the anti-rhinitis drug fluticasone furoate.
Fluticasone furoate is a novel glucocorticoid receptor agonist marketed as a treatment for seasonal and perennial allergic rhinitis. Forced degradation of fluticasone furoate under conditions of light led to a number of degradation products, the structures of which were elucidated using mass spectrometry and a range of one and two-dimensional NMR experiments. Three structures were derived, including two which involved a rearrangement of the steroid ring A to give cross-linked degradation products. The results demonstrate the applicability of a previously observed mechanism of photodegradation to fluticasone furoate.
Isolation and structural characterization of novel photolytic degradation impurities of Deflazacort using Q‐TOF, 2D‐NMR and FTIR
HIGHLIGHTSForced degradation of Deflazacort in ultra‐violet (light) condition.Isolation and characterization of 2 novel degradation products.Structural elucidation using MS‐qTOF, 1D/2D NMR, IR. ABSTRACT Forced Degradation of Deflazacort drug substance in ultraviolet light condition resulted into a number of significant degradation products. Two of these degradation products were found to be unknown during the study and marked as DD‐I and DD‐II. Thus, the objective of this work is to investigate and identify these two novel degradation products of DFZ. The isolation method for these new degradation products were developed using a new reverse‐phase high performance liquid chromatography (HPLC). DD‐I and DD‐II, eluting at 0.53 and 1.57 relative retention times with respect to Deflazacort (DFZ) peak respectively, were isolated from reaction mass using preparative HPLC and their structures were elucidated using high resolution MS, multidimensional NMR and FTIR spectroscopic techniques. To best of our knowledge, these two degradation products are novel impurities which are not discussed in any form of publication yet.
Novel method for the determination of the methoxyl content in lignin by headspace gas chromatography.
The paper reports on a headspace gas chromatographic (HS-GC) method for the determination of methoxyl in lignin. The method involves the quantitive cleavage of methoxyl with hydroiodic acid (HI) to form methyl iodide in a closed headspace sample vial at 130 °C for 30 min. After HI has been added, the sample is neutralized by injecting a sodium hydroxide solution; the methyl iodide in the vial was determined by HS-GC using a flame ionization detector. The results showed that the method has an excellent measurement precision (RSD < 0.69%) and accuracy (RSD < 3.5%) for the quantification of methoxyl content in lignin. The present method is simple and accurate and can be used for the efficient determination of methoxy1 content in lignin and related materials.