Analysis of dexamethasone and prednisolone residues in bovine milk using matrix solid phase dispersion-liquid chromatography with ultraviolet detection

SENSOR FOR PREDNISOLONE DETECTION IN SPORTS DOPING

ABSTRACT Introduction: Prednisolone causes pro-inflammatory impulses to be inhibited and anti-inflammatory signals to be promoted. As a result, it alters how the body's immune system reacts to certain diseases. The World Anti-Doping Agency, however, has banned SNP and other glucocorticosteroids. An electrochemical sensor can be developed using a gold nanocomposite, polypyrrole nanoparticles and synthesized carbon nanotubes (Au-PPy NPs@CNTs). Objective: Develop an electrochemical sensor to detect prednisolone. Method: Au-PPy NPs@CNTs nanocomposite was chemically synthesized with a modified glassy carbon electrode (GCE) surface. Results: According to SEM data, the nanocomposite was composed of amorphous Au NPs, and PPy NPs deposited in tubes strongly entangled in a CNTs network. The wide linear range and low detection limit of the Au-PPy NPs@CNTs/GCE as prednisolone sensors were attributed to the combined catalytic performance of the Au and PPy NPs@CNTs nanostructures. Conclusion: The results of prednisolone detection in each specimen using the amperometric method indicated good accuracy. The accuracy and precision of Au-PPy NPs@CNTs/GCE for prednisolone detection were explored in blood samples from 5 young athletes aged 20-24 years who used prednisolone tablets (RSD less than 4.25%). In addition to monitoring prednisolone concentrations in athletes’ serum, Au-PPy NPs@CNTs/GCE can be used as a reliable prednisolone sensor. Level of evidence II; Therapeutic studies - investigating treatment outcomes.

Determination of eight endocrine disruptor pesticides in bovine milk at trace levels by dispersive liquid-liquid microextraction followed by GC-MS determination

Endocrine disrupting chemicals are chemicals that interfere with any aspect of the endocrine system. Several natural and synthetic chemicals, including pesticides, have been identified as endocrine disruptors, which potentially inhibit the reproductive activity of the hormonal system. The pervasive occurrence with trace level concentrations and extensive variety are the reported characteristics of these chemicals. In this study, a dispersive liquid-liquid microextraction method coupled with gas chromatography and mass spectrometry for the determination of eight potential endocrine disruptor pesticides (Lindane, Diazinon, Fenitrothion, Malathion, Aldrin, α-Endosulfan, β-Endosulfan, Methoxychlor) in bovine milk samples was developed. Several parameters that can influence the extraction efficiency were studied. Under optimized conditions, the calibration curves of all eight analytes presented coefficient of determination higher than 0.998 (range level of 2.0-1000 ng/mL). The limits of detection and quantification ranged from 0.90 to 5.00 ng/mL and 2.50 to 15.0 ng/mL, respectively.

Solid Dosage Forms of Dexamethasone Sodium Phosphate Intended for Pediatric Use: Formulation and Stability Studies

Undesirable taste has always been a key issue for oral dosage forms. The aim of the present study was to co-formulate dexamethasone sodium phosphate (DSP), in common pediatric oral forms, using sweet preserves and/or different types of chocolate as excipients. An array of different kinds of chocolate were co-formulated with DSP and were further characterized by means of dynamic light scattering (DLS), x-ray diffraction (XRD), differential scanning calorimetry (DSC) and Fourier-transform infrared (FT-IR) spectroscopy. For the assay of active pharmaceutical ingredient (API), the chocolate samples were pre-treated by means of liquid extraction and analyzed using an high-performance liquid chromatographic (HPLC) method with a strong anion exchange column and a phosphate buffer (17 mM, pH = 3)/acetonitrile, 50:50 v/v as mobile phase. The developed chromatographic method was validated based on the International Conference on Harmonization (ICH) guidelines (%Mean Recovery = 99.4% and %Relative Standard Deviation, RSD = 0.43%). Furthermore, dissolution and in vitro digestion tests of chocolate formulations were evaluated. The DSP was found to be stable for at least 1 year in prepared preparations.

Targeted analysis and determination of β-agonists, hormones, glucocorticoid and psychiatric drugs in feed by liquid chromatography with electrospray ionization tandem mass spectrometry

A comprehensive strategy combining a quantitative method was developed for 30 banned drugs including β-agonists, hormones, glucocorticoid and psychiatric drugs in swine and chicken feeds. This rapid, simple and effective extraction method was based on matrix solid-phase dispersion and electrospray ionization tandem mass spectrometry. The quantitative method was validated after previous statistical optimization of the main parameters of matrix solid-phase dispersion. The limit of quantification of dopamine hydrochloride, chlormadinone acetate, melengestrol acetate, testosterone propionate, nandrolone and midazolam was 2 μg/kg and that of the other 24 drugs was 1 μg/kg. The recoveries of β-agonists, hormones, glucocorticoid and psychiatric drugs spiked in swine and chicken feeds at a concentration range of 1-8 μg/kg were above 70.1% with inter-day relative standard deviations less than 15.8%. The analytical strategy was applied to 100 feed samples collected from a local market in Wuhan (China). Clenbuterol, ractopamine and melengestrol acetate were identified and quantified at the level 0.2∼3.5 μg/kg. The rapid and reliable method can be used to efficiently separate, characterize and quantify the residues of 30 banned drugs in swine and chicken feeds with advantages of simple pretreatment and environmental friendly nature.

Molecularly Imprinted Dispersive Solid-Phase Extraction for the Determination of Triazine Herbicides in Grape Seeds by High-Performance Liquid Chromatography

Molecular imprinting technique, regarded as one of the current state-of-the-art researches, was incorporated with the simple dispersive solid-phase extraction (MI-DSPE) in this work for the extraction of triazine herbicides in grape seeds. The atrazine molecularly imprinted polymers (MIPs) were successfully prepared and characterized by scanning electron microscopy and Fourier transform infrared spectroscopy. The imprinting particles were used as the adsorbent in DSPE. Thus, a simple, rapid and selective method based on MIPs coupled with DSPE was established for the simultaneous cleaning-up and quantitative extraction of four triazine herbicides in grape seeds. The experiment parameters, including type of washing solvents, washing time and type of eluting solvents, were investigated and optimized. The performance of the present method was validated by high-performance liquid chromatography. Good linear responses were obtained in concentration range of 0.010-5.0 µg g(-1)with correlation coefficients (r(2)) higher than 0.9993. The recoveries at two spiked levels (1.0 and 2.0 µg g(-1)) were between 81.2 and 113.0% with relative deviations ranging from 1.2 to 10.7%. The limits of detection were ranged between 0.006 and 0.013 µg g(-1), which were lower than the values required by European regulations.

Computation of geometric representation of novel spectrophotometric methods used for the analysis of minor components in pharmaceutical preparations

Novel spectrophotometric methods were applied for the determination of the minor component tetryzoline HCl (TZH) in its ternary mixture with ofloxacin (OFX) and prednisolone acetate (PA) in the ratio of (1:5:7.5), and in its binary mixture with sodium cromoglicate (SCG) in the ratio of (1:80). The novel spectrophotometric methods determined the minor component (TZH) successfully in the two selected mixtures by computing the geometrical relationship of either standard addition or subtraction. The novel spectrophotometric methods are: geometrical amplitude modulation (GAM), geometrical induced amplitude modulation (GIAM), ratio H-point standard addition method (RHPSAM) and compensated area under the curve (CAUC). The proposed methods were successfully applied for the determination of the minor component TZH below its concentration range. The methods were validated as per ICH guidelines where accuracy, repeatability, inter-day precision and robustness were found to be within the acceptable limits. The results obtained from the proposed methods were statistically compared with official ones where no significant difference was observed. No difference was observed between the obtained results when compared to the reported HPLC method, which proved that the developed methods could be alternative to HPLC techniques in quality control laboratories.

A comparative study of different aspects of manipulating ratio spectra applied for ternary mixtures: derivative spectrophotometry versus wavelet transform

This work represents a comparative study of different aspects of manipulating ratio spectra, which are: double divisor ratio spectra derivative (DR-DD), area under curve of derivative ratio (DR-AUC) and its novel approach, namely area under the curve correction method (AUCCM) applied for overlapped spectra; successive derivative of ratio spectra (SDR) and continuous wavelet transform (CWT) methods. The proposed methods represent different aspects of manipulating ratio spectra of the ternary mixture of Ofloxacin (OFX), Prednisolone acetate (PA) and Tetryzoline HCl (TZH) combined in eye drops in the presence of benzalkonium chloride as a preservative. The proposed methods were checked using laboratory-prepared mixtures and were successfully applied for the analysis of pharmaceutical formulation containing the cited drugs. The proposed methods were validated according to the ICH guidelines. A comparative study was conducted between those methods regarding simplicity, limitation and sensitivity. The obtained results were statistically compared with those obtained from the reported HPLC method, showing no significant difference with respect to accuracy and precision.

Column performance study of different variants of liquid chromatographic technique: an application on pharmaceutical ternary mixtures containing tetryzoline

High-performance liquid chromatography (HPLC), ultra-performance liquid chromatography (UPLC) and rapid resolution liquid chromatographic (RRLC) methods have been developed and validated for the separation and quantitation of both or either of two ternary mixtures present in ophthalmic solutions. The first mixture contains chloramphenicol, dexamethasone sodium phosphate and tetryzoline HCl (TZH); while the second one contains ofloxacin, prednisolone acetate and TZH. Both preparations contain benzalkonium chloride as a preservative. The columns used were a HPLC column (C18 5 µm particle size), a RRLC column (C18 2.6 µm particle size) and a UPLC column (C18 1.7 µm particle size). A comparative study was conducted to illustrate the effect of the change in column particle size and dimensions on the other chromatographic conditions, backpressure and the separation of both ternary mixtures. The methods were validated as per ICH guidelines where accuracy, repeatability, interday precision and robustness were found to be within the acceptable limits. The RRLC column provided shorter run time and better resolution than HPLC, while the UPLC column gave the shortest run time for all columns. The RRLC column resulted in minimum backpressure, so it could be used with any HPLC instrument, which makes the method more practical and economic. The results obtained from the proposed methods were statistically compared with official ones where no significant difference was observed.

Simultaneous determination of corticosteroids, androgens, and progesterone in river water by liquid chromatography-tandem mass spectrometry

The assessment of steroidal hormones in the environment requires sensitive and selective analytical techniques suitable for sample matrices. This paper reports a simple method to analyze simultaneously six corticosteroids (triamcinolone, cortisol, dexamethasone, flumethasone, prednisolone, triamcinolone acetonide), four androgens (boldenone, epitestosterone, methyltestosterone, nortestosterone), and progesterone in river and drinking water sources. The developed method is based on a single solid-phase extraction (SPE) followed by liquid chromatography/tandem mass spectrometry (LC-MS/MS) with atmospheric pressure chemical ionization (APCI). The main advantage of this method over other methods includes the use of a single SPE with a low volume cartridge for sample preparation, separation of steroids on alkyl-amide stationary phase with no matrix interferences by LC-MS/MS analysis, and simultaneous analysis of more than two groups of steroids. The method was characterized by generally good performance, analyzing three groups of steroids using 100 and 1000mL samples with average recovery ranges of 80-109% and 68-126%, respectively at a level of 1ngL(-1). The limit of detection (LOD) ranged from 0.06 to 0.2 and 0.01-0.21ngL(-1) for 100mL and 1000mL samples volumes, respectively. Sixty samples of Danube River and drinking water sources from different regions of Hungary were collected to analyze target steroids in two sampling periods in 2008 and 2009. Steroids, except cortisol, dexamethasone, flumethasone, prednisolone, epitestosterone and progesterone were below detection limits. Endogenous steroids (cortisol, epitestosterone, progesterone) were present in the concentration range of 0.08-2.67ngL(-1) while synthetic corticosteroids (dexamethasone, flumethasone, and prednisolone) varied from 0.064 to 1.43ngL(-1). Steroids were present in river water, except progesterone, which was present only in ground water. Levels of steroids are compared with other rivers in the world and were briefly discussed.