A Molecular Imprinted Polymer as a Flow-Through Optical Sensor for Oxazepam.

A flow-through optosensing system for oxazepam recognition with fluorescence detection was performed by means of a molecular imprinted polymer based on its acid hydrolysis product, 2-amino-5-chlorobenzophenone. The synthesis was conducted via a noncovalent imprinting methodology, using methacrylic acid as a functional monomer and ethylene glycol dimethacrylate as a cross-linking agent. Hydrolysis (types and concentration of acids), polymer retention capacity, binding properties, and elution (selectivity and reversibility) conditions were optimized. The selected molecular imprinted polymer had a molar ratio composition of 1 : 6 : 45 (template : functional monomer : cross-linker). The proposed method was applied to the determination of oxazepam in a pharmaceutical formulation. External standard calibration, standard additions calibration, and Youden's calibration were carried out in order to evaluate constant and proportional errors due to the matrix. The developed metabolite-based recognition system for benzodiazepines is an innovative procedure that could be followed in routine and quality control assays.

Binding of several benzodiazepines to bovine serum albumin: Fluorescence study.

The interactions of lorazepam, oxazepam and bromazepam with bovine serum albumin (BSA) were studied by fluorescence spectrometry. The Stern-Volmer quenching constants and corresponding thermodynamic parameters DeltaH, DeltaG and DeltaS were calculated. The binding constants and the number of binding sites were also investigated. The distances between the donor (BSA) and the acceptors (benzodiazepines) were obtained according to fluorescence resonance energy transfer and conformational changes of BSA were observed from synchronous fluorescence spectra.

Simultaneous determination of carbaryl and 1-naphthol by first-derivative synchronous non-protected room temperature phosphorescence.

The applicability of non-protected room temperature phosphorescence (NP-RTP) in real samples was demonstrated in the present work. In this methodology, only two reagents, potassium iodide and sodium sulfite, were used to obtain phosphorescent signals. Overlapping of the phosphorescence spectra was resolved by using first-derivative synchronous phosphorimetry. The synchronous first-derivative spectra of carbaryl and 1-naphthol in the mixture were completely separated by changing the synchronous wavelength interval; with 240 nm the first-derivative spectra of carbaryl were recorded, while with 200 nm those of 1-naphthol appeared. The intensities in the spectra were proportional to the concentration of carbaryl and 1-naphthol. The calibration graphs were linear up to at least 1.1 x 10(-5) mol L(-1) for carbaryl and 1.3 x 10(-5) mol L(-1) for 1-naphthol, and the correlation coefficients were 0.9971 and 0.9932, respectively. Carbaryl and 1-naphthol were successfully determined by the proposed method in a hydrolyzed sample of a commercial formulation.