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Combining short‐acting and long‐acting insulin analogs was a real challenge that was overcome by NovoNordisk through the co‐formulation of insulin aspart and insulin degludec in single‐dosage form. The proposed study provides a simple, short, and reliable HPLC method with diode array detection that is developed and validated for the simultaneous determination of insulin aspart and insulin degludec in human plasma. The proposed method achieved good separation between the two analytes utilizing a C8 column at 35°C in a very short run time (6 min), with a simple, low‐cost, and reliable extraction method through precipitation of plasma protein. Gradient elution was applied using a mobile phase consisting of 0.1 M sodium sulfate (pH 3.4) and acetonitrile. The method was validated according to EMA Guideline on Bioanalytical Validation. The proposed method had a linear range from 3.0 to 300 μg/mL for insulin aspart and from 3.5 to 300 μg/mL for insulin degludec. The intra‐ and inter‐day precision of insulin aspart were 0.36–3.33% and 1.59–8.84%, respectively, and accuracy was between 10.06 and 3.09% The intra‐ and inter‐day precision of insulin degludec were 0.29–1.93% and 0.89–5.14%, respectively, and accuracy was between −5.29 and 3.91%. [ABSTRACT FROM AUTHOR]

Solid–liquid extraction, ultrasonic-assisted extraction and matrix solid-phase dispersion (MSPD) were optimized and compared in terms of recoveries for the simultaneous extraction of indole (IND) and 2,4-dichlorophenol (DCP) from catfish samples and for the extraction of IND alone from potato samples. Applying high-performance liquid chromatography (HPLC-DAD) procedure using mobile phase of methanol : water (65 : 35) at 280 nm, MSPD was the method of choice for the extraction of IND and DCP from catfish and, also, for IND from potato. The extraction recoveries of MSPD were in the range (97.9-99.7%) and (99.8-100.6%); for IND and DCP, respectively, in catfish samples and (98.4-99.7%) for IND alone in potato samples. Solid-phase extraction (SPE) was chosen the method of choice for the extraction of DCP from fish farms water samples after optimization and comparison with direct sample injection and extraction recoveries were in the range (97.9-100.3%). Kinetics were further studied to follow each of production of IND in catfish during storage at different temperatures and uptake of DCP by tilapia in fish farms water samples using MSPD-HPLC and SPE-HPLC, respectively. [ABSTRACT FROM AUTHOR]

A new, simple, selective, reproducible and sensitive stability-indicating liquid chromatographic method was developed and subsequently validated for the determination of saxagliptin (SXG). SXG was subjected to oxidation, thermal, acid hydrolysis, alkali hydrolysis and photodegradation according to ICH guidelines. The major degradation products were separated from the pure drug and the proposed structures' elucidation was performed, using an LC-MS technique. Isocratic chromatographic elution was achieved on a Symmetryw C18 column (150 × 4.6 mm, 5 mm), using a mobile phase of potassium dihydrogen phosphate buffer (pH 4.6)-acetonitrile-methanol (40 : 30 : 30, v/v/v) at a flow rate of 1 mL min-1 with UV detection at 208 nm. Linearity, accuracy and precision were found to be acceptable over the concentration range of 25-400 mg mL-1. All the results were statistically compared with the reference method, using one-way analysis of variance. The developed method was validated and proved to be specific and accurate for quality control of SXG in pharmaceutical dosage form. [ABSTRACT FROM AUTHOR]

Antimicrobial resistance (AMR) is a neglected issue that poses a serious global threat to public health, causing long-term negative consequences at both humanitarian and economic levels. Herein, we report an unprecedented economic fabrication method of seven potentiometric screen-printed sensors for the ultra-trace determination of gemifloxacin (GEMI) as a model of the fluoroquinolones antibiotics deeply involved in the growing AMR problem. Sensors were constructed by depositing homemade carbon ink on a recycled X-ray sheet, patterned using stencils printed with an office printer in simple, cost-effective steps requiring no sophisticated equipment. Four sensors were modified using carbon quantum dots (CQDs) synthesized from dextrose through a single-step method. Sensors exhibited a linear response in the concentration ranges 10−5–10−2 M (sensors 1, 3 and 4), 10−6–10−3 M (sensor 2) and 10−6–10−2 M (sensors 5, 6 and 7). LOD allowed tracing of the target drug at a nano-molar level down to 210 nM. GEMI was successfully determined in pharmaceutical formulations and different water samples without any pretreatment steps with satisfactory recovery (96.93–105.28% with SD values < 3). All sensors revealed a long lifetime of up to several months and are considered promising tools for monitoring water quality and efficiency of water treatment measures. [ABSTRACT FROM AUTHOR]