Analysis of underivatized gentamicin by capillary electrophoresis with UV detection

Fortified Dual-Spectral Overlap with Enhanced Colorimetric/Fluorescence Dual-Response Immunochromatography for On-Site Bimodal-Type Gentamicin Monitoring

Immunochromatography (ICA) remains untapped toward enhanced sensitivity and applicability for fulfilling the nuts and bolts of on-site food safety surveillance. Herein, we report a fortified dual-spectral overlap with enhanced colorimetric/fluorescence dual-response ICA for on-site bimodal-type gentamicin (Gen) monitoring by employing polydopamine (PDA)-coated AuNPs (APDA) simultaneously serving as a colorimetric reporter and a fluorescence quencher. Availing of the enhanced colorimetric response that originated from the PDA layer, the resultant APDA exhibits less required antibody and immunoprobes in a single immunoassay, which facilitates improved antibody utilization efficiency and immuno-recognition in APDA-ICA. Further integrated with the advantageous features of fortified excitation and emission dual-spectral overlap for the Arg/ATT-AuNCs, this APDA-ICA with a "turn on/off" pattern achieves the visual limits of detection of 1.0 and 0.5 ng mL-1 for colorimetric and fluorescence patterns (25- and 50-fold lower than standard AuNPs-ICA). Moreover, the excellent self-calibration and satisfactory recovery of 79.03-118.04% were shown in the on-site visual colorimetric-fluorescence analysis for Gen in real environmental media (including real river water, an urban aquaculture water body, an aquatic product, and an animal byproduct). This work provides the feasibility of exploiting fortified dual-spectral overlap with an enhanced colorimetric/fluorescence dual response for safeguarding food safety and public health.

CE-DAD-MS/MS in the simultaneous determination and identification of selected antibiotic drugs and their metabolites in human urine samples

In this study, a new analytical method was developed and validated for the simultaneous analysis of antibiotic drugs (amoxicillin, cefotaxime, ciprofloxacin, clindamycin, linezolid, metronidazole) and their metabolites (amoxycilloic acid, amoxicillin diketopiperazine, 3-desacetyl cefotaxime lactone, clindamycin sulfoxide, ciprofloxacin piperazinyl-N4-sulfate, linezolid N-oxide, metronidazole-OH) in human urine. Capillary electrophoresis (CE) along with the tandem mass spectrometry (MS/MS) was used to determine and identify all analytes. Appropriate conditions for MS/MS measurements along with the use of the central composite design were optimized. The effects of different analytical conditions (the composition, the concentration, and the pH value of the background electrolyte, the time and pressure of the injection, the capillary temperature and influence of the organic modifier) on the migration and separation of antibiotic drugs and metabolites were examined using the CE-DAD. The analytical procedure was linear for concentrations ranging from 20 to 1000 ng/mL, with determination coefficients higher than 0.99 for all the analytes. The validated analytical procedure was then applied to the measurement of antibiotic drugs and their metabolites in human urine samples.

Derivatization-free determination of aminoglycosides by CZE-UV in pharmaceutical formulations

Aminoglycosides are a relevant class of antibiotics widely used by medics and veterinaries. There are a variety of reasons that make their determination relevant, such as quality control, environment and food contamination assessment, drug-release studies, among others. The lack of a chromophore makes aminoglycoside spectrophotometric detection particularly challenging, often requiring derivatization. In this work, an indirect detection method, making use of imidazole as a probe, applying CZE was successfully tested. It did not require derivatization, which simplified the sample preparation. Suitable figures of merit were obtained; recoveries between 95 and 105%, adequate repeatability and precision, correlation coefficients (r) above 0.998, and limits of detection (LODs) of 3.2 and 11 mg/L for gentamicin and paromomycin, respectively. As a proof-of-concept, it was also applied in a simple controlled release experiment that was well fitted using the Hill equation.

Green synthesis of methyl gallate conjugated silver nanoparticles: a colorimetric probe for gentamicin

A highly efficient colorimetric sensor for gentamicin is proposed based on methyl gallate conjugated silver nanoparticles.

Long-term stability of gentamicin sulfate-ethylenediaminetetraacetic acid disodium salt (EDTA-Na2) solution for catheter locks

A lock solution composed of gentamicin sulfate (5 mg/mL) and ethylenediaminetetraacetic acid disodium salt (EDTA-Na₂, 30 mg/mL) could fully eradicate in vivo bacterial biofilms in totally implantable venous access ports (TIVAP). In this study, fabrication, conditioning and sterilization processes of antimicrobial lock solution (ALS) were detailed and completed by a stability study. Stability of ALS was conducted for 12 months in vial (25 °C ± 2 °C, 60% ± 5% relative humidity (RH), and at 40 °C ± 2 °C, RH 75% ± 5%) and for 24 h and 72 h in TIVAP (40 °C ± 2 °C, RH 75% ± 5%). A stability indicating HPLC assay with UV detection for simultaneous quantification of gentamicin sulfate and EDTA-Na₂ was developed. ALS was assayed by ion-pairing high performance liquid chromatography (HPLC) needing gentamicin derivatization, EDTA-Na₂ metallocomplexation of samples and gradient mobile phase. HPLC methods to separate four gentamicin components and EDTA-Na₂ were validated. Efficiency of sterility procedure and conditioning of ALS was confirmed by bacterial endotoxins and sterility tests. Physicochemical stability of ALS was determined by visual inspection, osmolality, pH, and sub-visible particle counting. Results confirmed that the stability of ALS in vials was maintained for 12 months and 24 h and 72 h in TIVAP.

Cysteamine-Modified Gold Nanoparticles as a Colorimetric Sensor for the Rapid Detection of Gentamicin

A simple, rapid, and specific colorimetric method for gentamicin detection using cysteamine-modified gold nanoparticles (cys-AuNPs) has been developed. The maximum residue limits of gentamicin allowed in foods are typically below 100 nM, so an effective detection method for low concentrations of the drug is required. The aggregation of gold nanoparticles (AuNPs) was used as the basis for this method, and adding cysteamine to the AuNPs helped to enhance their aggregative abilities. The cys-AuNPs are capable of detecting gentamicin concentrations as low as 12.45 nM in water, which could be quantified using UV-vis spectroscopy. Samples extracted from skim milk with a simple pretreatment showed that gentamicin concentrations down to at least 100 nM could be observed using the cys-AuNPs. This study demonstrates the ability of the cys-AuNPs to rapidly detect and quantify gentamicin in both simple and complex matrices.

PRACTICAL APPLICATION

This study demonstrates that cysteamine-modified gold nanoparticles could be used as a rapid and efficient tool for gentamicin detection. This technique is cheaper, simpler, and more effective than many other methods that are currently used for detecting the antibiotic in industrial and commercial applications. It has a great potential to be practically applied as a rapid screening method for gentamicin and gentamicin-like compounds in food and environmental samples.

Micellar Electrokinetic Chromatography of Aminoglycosides

The components of the aminoglycosides, e.g., gentamicin, sisomicin, netilmicin, kanamycin, amikacin, and tobramycin, and related impurities of these antibiotics can be separated by means of micellar electrokinetic chromatography (MEKC). Derivatization with o-phthaldialdehyde and thioglycolic acid is found to be appropriate for these antibiotics. The background electrolyte was composed of sodium tetraborate (100 mM), sodium deoxycholate (20 mM), and β-cyclodextrin (15 mM) having a pH value of 10.0. This method is valid for evaluation of gentamicin, kanamycin, and tobramycin. It has to be adopted for amikacin, paromomycin, neomycin, and netilmicin.

Development of a Fourier transform infrared spectroscopy coupled to UV-Visible analysis technique for aminosides and glycopeptides quantitation in antibiotic locks

Antibiotic Lock technique maintains catheters' sterility in high-risk patients with long-term parenteral nutrition. In our institution, vancomycin, teicoplanin, amikacin and gentamicin locks are prepared in the pharmaceutical department. In order to insure patient safety and to comply to regulatory requirements, antibiotic locks are submitted to qualitative and quantitative assays prior to their release. The aim of this study was to develop an alternative quantitation technique for each of these 4 antibiotics, using a Fourier transform infrared (FTIR) coupled to UV-Visible spectroscopy and to compare results to HPLC or Immunochemistry assays. Prevalidation studies permitted to assess spectroscopic conditions used for antibiotic locks quantitation: FTIR/UV combinations were used for amikacin (1091-1115cm(-1) and 208-224nm), vancomycin (1222-1240cm(-1) and 276-280nm), and teicoplanin (1226-1230cm(-1) and 278-282nm). Gentamicin was quantified with FTIR only (1045-1169cm(-1) and 2715-2850cm(-1)) due to interferences in UV domain of parabens, preservatives present in the commercial brand used to prepare locks. For all AL, the method was linear (R(2)=0.996 to 0.999), accurate, repeatable (intraday RSD%: from 2.9 to 7.1% and inter-days RSD%: 2.9 to 5.1%) and precise. Compared to the reference methods, the FTIR/UV method appeared tightly correlated (Pearson factor: 97.4 to 99.9%) and did not show significant difference in recovery determinations. We developed a new simple reliable analysis technique for antibiotics quantitation in locks using an original association of FTIR and UV analysis, allowing a short time analysis to identify and quantify the studied antibiotics.

In Vitro Drug Release Activity from Core/Shell Electrospun MATS of sPLA-cPEG/GS and sPLA/CA-cPEG/GS

In this research, the core-shell structured fiber was fabricated by coaxial electrospinning technique. A set of biodegradable polymers namely polylactic acid (PLA) and cellulose acetate (CA) were used as the shell material. Gentamicin sulfate (GS) as antimicrobial drug with polyethylene glycol (PEG) was used as the core structure. PEG formed the core section of the coreshell fibers for GS encapsulation.In-vitrodrug release activity of the core-shell fibers was determined by total immersion method in pH 7.4 phosphate buffer solutions (PBS). It was found that core-shell fibers sPLA-cPEG/GS exhibit higher initial release compared to that of core-shell fibers sPLA/CA-cPEG/GS.

Determination of Gentamicin Sulphate Composition and Related Substances in Pharmaceutical Preparations by LC with Charged Aerosol Detection

A new, simple and repeatable liquid chromatography method with charged aerosol detection (LC-CAD) for the determination of gentamicin sulphate composition and related substances has been developed. Gentamicin lacks of chromophores, therefore its determination is quite problematic. Using a universal CAD enables to achieve good separation without sample derivatization. Mass spectrometry was employed to confirm the LC-CAD peak profile. The proposed method was validated and applied for the determination of gentamicin sulphate composition and related substances in pharmaceutical preparations.