Derivative constant wavelength synchronous fluorescence spectrometry for the simultaneous detection of cefadrine and cefadroxil in water samples.

A sensitive accurate spectrofluorimetric technique was developed to detect cefadroxil and cefradine traces in water samples simultaneously, by applying a procedure based on the formation of hydrolysis products corresponding to these compounds by sodium hydroxide (1 N NaOH) treatment. The conventional and the synchronous fluorescence spectra of these hydrolyzed products were totally overlapped making resolving of this mixture impossible. The second-derivative constant-wavelength synchronous fluorescence spectra allowed their detection simultaneously in a single scan after experimental conditions optimization, which was measured at 390 nm and 379 nm for cefadroxil and cefradine, respectively at Δλ = 30.0. The calibration curves between derivative synchronous fluorescence intensity and drugs concentration showed suitable linear correlation in the range of 0.1 to 5 µg.mL-1 for cefadroxil and 0.5-10 µg.mL-1 for cefradine. The proposed fluorimetric method is superior in being simple, environmental friendly and cost effective in comparison to the previously published reported methods.

Application of Chemometrics for Spectral Resolving and Determination of Three Analgesics in Water Samples.

BACKGROUND: Chemometrics is a discipline that allows the spectral resolution of drugs in a complicated matrix (e.g., environmental water samples) as an alternative to chromatographic methods. OBJECTIVE: Three analgesics were traced in wastewater samples with simple and cost-effective multivariate approaches using spectrophotometric data. METHODS AND RESULTS: Four chemometric approaches were applied for the simultaneous determination of diclofenac, paracetamol, and ibuprofen. Partial least squares (PLS), principal component regression (PCR), artificial neural networks (ANN), and multivariate curve resolution (MCR)-alternating least squares (ALS) were selected. The presented methods were compared and validated for their qualitative and quantitative analyses. Moreover, statistical comparison between the results obtained by the proposed methods and the official methods showed no significant differences. CONCLUSIONS: The proposed multivariate calibrations were accurate and specific for quantitative analysis of the studied components. MCR-ALS is the only method that has the capacity for both the quantitative and qualitative analysis of the studied drugs. HIGHLIGHTS: Four chemometric approaches were used for analysis of severally overlapped ternary mixture of three analgesics. The analytical performance of PCR, PLS, MCR-ALS, and ANN was compared and validated in terms of root mean square error of calibration (RMSEC), SE of prediction, and recoveries. ANN gave the highest predicted concentrations with the lowest RMSEC and root mean square error of prediction. MCR-ALS has the capacity for both qualitative and quantitative measurement. The methods have been effectively applied for real samples and compared to official methods.

Chemometrics for resolving spectral data of cephalosporines and tracing their residue in waste water samples.

Chemometrics approaches have been used in this work to trace cephalosporins in aquatic system. Principal component regression (PCR), partial least squares (PLS), multivariate curve resolution-alternating least squares (MCR-ALS), and artificial neural networks (ANN) were compared to resolve the severally overlapped spectrum of three selected cephalosporins; cefprozil, cefradine and cefadroxil. The analytical performance of chemometric methods was compared in terms of errors. Artificial neural networks provide good recoveries with lowest error. Satisfactory results were obtained for the proposed chemometric methods whereas ANN showed better analytical performance. The qualitative meaning in MCR-ALS transformation provided very well correlations between the pure and estimated spectra of the three components. This multivariate processing of spectrophotometric data could successfully detect the studied antibiotics in waste water samples and compared favorably to alternative costly chromatographic methods.

Comparative study of different chromatographic techniques for the analysis of multi-residues of some approved antimicrobials in fish tissues.

Two chromatographic methods were developed, optimized and validated for the simultaneous determination of three approved aquaculture antimicrobials, namely sulphadimethoxine sodium, trimethoprim and florphenicol in fish tissues. The developed methods were based on simple liquid extraction technique. The first method employs thin-layer chromatography as a clean-up procedure coupled with densitometric determination for the separated drugs. The second method is an HPLC one using X-Terra™ C18 column. Several mobile-phase systems and extracting solvents were tried to optimize the separation and the extraction procedures from fish tissues. The procedures were applied for the analysis of spiked fish tissue samples at three different concentration levels (10, 50 and 100 ppm). A comparative study was conducted between the proposed methods to discuss the advantage of each one. The methods were validated according to the international conference on harmonization guidelines. The proposed methods were successfully applied for the determination of the studied drugs in spiked fish tissues, pure powders and in their veterinary pharmaceutical formulation.

Multi-residues determination of antimicrobials in fish tissues by HPLC-ESI-MS/MS method.

A rapid, simple, sensitive and specific LC-MS/MS method was developed and validated for the simultaneous quantification of four antimicrobials commonly used in aquaculture, namely ciprofloxacin (CPX), trimethoprim (TMP), sulphadimethoxine (SDM) and florphenicol (FLOR) in fish tissues. The LC-MS/MS was operated under the multiple-reaction monitoring mode using electrospray ionization. Sample preparation involves simple liquid extraction step followed by post-extraction clean-up step with n-hexane. The purified extracts were chromatographed on Agilent Poroshell 120 EC, C18 (50 mm × 3 mm, 2.7 µm) column by pumping an isocratic mobile phase consisting of 0.1% formic acid in water:0.1% formic acid in methanol (20:80, by volume) at a flow rate of 0.4 mL/min. A detailed validation of the method was performed as per FDA guidelines and the standard curves were found to be linear in the range of 1-100 ng/g for both CPX and TMP, 0.5-100 ng/g for SDM and 1-50 ng/g for FLOR. The intra-day and inter-day precision and accuracy of the results were within the acceptable limits. A run time of 1.5 min for each sample made it possible to analyze multiple fish tissue samples per day. The developed assay method was successfully applied for the detection of antimicrobials in real fish tissue samples obtained from different fish farms.

Simultaneous determination of sitagliptin and metformin in their pharmaceutical formulation.

Two simple, accurate, and rapid methods were developed for simultaneous determination of sitagliptin phosphate and metformin hydrochloride in their pharmaceutical formulation. The first is a TLC method coupled with densitometry. The second is an HPLC method using a C18 column. The selectivity of the proposed methods was checked using laboratory-prepared mixtures. The proposed methods were successfully applied to the analysis of sitagliptin phosphate and metformin hydrochloride in bulk form and in their pharmaceutical formulation without interference from other additives.