Determination of Ondansetron by Spectrofluorimetry: Application to Forced Degradation Study, Pharmaceuticals and Human Plasma.

The current manuscript describes a validated, responsive and rapid spectrofluorimetric method for quantifying ondansetron (OND) in authentic form, spiked human plasma and dosage forms. This is the first reported fluorescence study of Ondansetron in Triton X 100 system. Various variables affecting fluorescence response were studied precisely and optimised. The described method involved the fluorescence measurement in Triton X 100 system at λem/λex 354/317 nm. The calibration plot attained linearity over concentration range of 0.2 - 2 µg/mL. The developed method has been extensively applied to degradation studies of OND as per International Conference on Harmonisation (ICH) guidelines by exposing to oxidative, thermal, photo, acidic and alkaline conditions and also the degradation pathway has been proposed.

A Micelle-Enhanced Spectrofluorimetric Determination of Pirfenidone: Application to Content Uniformity Testing and Human Urine.

The present manuscript gives a detailed account of highly selective, validated and sensitive method for quantification of pirfenidone in its pharmaceutical dosage forms and spiked human urine. The developed method is relied on the systematic study of the fluorescence action of Pirfenidone in Tween - 80 micellar medium. The Pirfenidone exhibits strong fluorescence at λem 396 nm upon excitation at λex 318 nm in Tween -80 medium. The fluorescence - concentration plot was linear over concentration range of 0.5 - 5 µg/mL. There was greater extent (1.02 fold) of enhancement in fluorescence intensity in presence of tween - 80 with very low limit of detection and quantitation of 0.04 µg/mL and 0.11 µg/mL respectively. The application of developed methodology is successfully applied to content uniformity testing and spiked human urine. The proposed study was successfully applied for analysis of pirfenidone in commercially available pharmaceutical formulations.

Synthesis and chelation properties of a new polymeric ligand derived from 1-amino-2-naphthol-4-sulfonic Acid.

A novel chelating resin for preconcentration of heavy metals from various seawater samples has been developed by condensing 1-amino-2-hydroxy-7-[(4-hydroxyphenyl)diazenyl] naphthalene-4-sulfonic acid (AHDNS) with formaldehyde (1:2 mole ratio) in the presence of oxalic acid as the catalyst. The resin thus obtained was used as a solid sorbent for the separation of divalent metal ions present at trace levels in seawater. The functionalized phenol (AHDNS) was characterized by spectral studies. The polymeric resin AHDNS-formaldehyde (AHDNS-F) obtained by condensing the functionalized phenol and formaldehyde was characterized by IR and NMR spectral studies. The chelating property of the AHDNS-F resin towards divalent metal ions was studied as a function of pH and in the presence of electrolyte. The metal uptake properties of the resin were determined by using an atomic absorption spectrophotometer. This procedure was validated for recovery of divalent metal ions from seawater samples. The recoveries of cadmium, cobalt, copper, manganese, lead, and zinc were above 92% under the optimum preconcentration conditions. The LOD was <0.73 µg/L and the RSDs were <2%. Thus, the AHDNS-F resin can be widely used as a solid sorbent for the preconcentration of trace metals at ppm levels in seawater samples.

Quantitative determination of melatonin in milk by LC-MS/MS.

A rapid, reliable and sensitive LC-MS/MS method for the determination of melatonin in milk was developed and validated. Sample was extracted with dichloromethane and cleaned by passing through Chem Elut solid phase extraction cartridge. The solvent was evaporated to dryness, reconstituted with methanol and analysed by LC-MS/MS on Agilent zorbax Eclipse XDB C-18 rapid resolution analytical column. The analytical procedure was found to be accurate, precise and linear. The method accuracy was 92.2 % (range 90.06-94.58) and the mean precision was 1.55 % and the calibration was linear for 1 to 150 pg mL(-1) (R(2) > 0.99), the lowest limit of quantification (LLOQ) was 1 pg mL(-1). 7-D Melatonin (7-DM) was used as an internal standard. This method was proved to be a promising method for the determination of melatonin for market milk and human milk samples.