Hollow porous molecularly imprinted polymer for highly selective clean-up followed by influential preconcentration of ultra-trace glibenclamide from bio-fluid.

In the present work, hollow porous molecularly imprinted polymer (HPMIP) was prepared via adopting a sacrificial support approach using glibenclamide (GB) as template, methacrylic acid (MAA) as functional monomer, ethylene glycol dimethacrylate as cross-linker (EGDMA) and mesoporous MCM-48 nanospheres as support. Owing to a short thickness of the foresaid HPMIP, a suitable steric structure was readily available that lead to fast and effective mass transfer of target analyte to sorbent and consequently supply high binding capacity. After ultrasonic-assisted dispersive solid phase extraction of urine sample, the analyte of interest was quantitatively pre-concentrated and determined by high performance liquid chromatography-ultraviolet detection (HPLC-UV). Influence of factors affecting the extraction efficiency such as sonication time, sample pH, sorbent dosage, and volumes of eluent and washing agents as well as their significant interactions were simultaneously optimized by experimental design methodology. Under optimized conditions, present method has linear response over concentration range of 10.0-3000.0µgL-1 in human urine samples with a satisfactory detection limit close to 3.5µgL-1. The inter-day precisions of the current method (coefficient of variation) are lower than 5%, while recoveries are more than 89.5%.

Selective separation and enrichment of glibenclamide in health foods using surface molecularly imprinted polymers prepared via dendritic grafting of magnetic nanoparticles.

In this paper, the novel surface molecularly imprinted polymers based on dendritic-grafting magnetic nanoparticles were developed to enrich and separate glibenclamide in health foods. The density functional theory method was used to give theoretical directions to the synthesis of molecularly imprinted polymers. The polymers were prepared by using magnetic nanoparticles as supporting materials, methacrylic acid as the functional monomer, and ethylene glycol dimethacrylate as the cross-linker. The characteristics of magnetic nanoparticles and polymers were measured by transmission electron microscope and SEM, respectively. The enriching ability of molecularly imprinted polymers was measured by Freundlich Isotherm. The molecularly imprinted polymers were used as dispersive SPE materials to enrich, separate, and detect glibenclamide in health foods by HPLC. The average recoveries of glibenclamide in spiked health foods were 81.46-93.53% with the RSD < 4.07%.

High-performance liquid chromatography quadrupole time-of-flight mass spectrometry method for the analysis of antidiabetic drugs in aqueous environmental samples.

Antidiabetic compounds are among the most prescribed pharmaceuticals. Nevertheless, their presence in the environment has been scarcely evaluated as there is no method for their determination in environmental samples. This paper reports the development of an analytical method for the determination of traditionally used antidiabetics (metformin and glibenclamide) and novel antidiabetics (vildagliptin, sitagliptin and pioglitazone). The method is based on solid-phase extraction and determination by high-performance liquid chromatography quadrupole time-of-flight mass spectrometry. The method was applied to effluent wastewater, river water and tap water. Mean recoveries of glibenclamide, vildagliptin, sitagliptin and pioglitazone in the matrices evaluated were in the range 78-83%; limits of quantification were in the range 0.4-4.3 ng L(-1); and precision values were in the range 2.2-13%. The high hydrophilicity and polarity of metformin complicated its simultaneous extraction. Chromabond Tetracycline cartridges and sample pH 8.5 were applied to the extraction of glibenclamide, vildagliptin, sitagliptin and pioglitazone. Oasis HLB cartridges, neutral sample pH and SDS as ion-pair reagent were used for the extraction of metformin. Validation results of metformin were not as favorable as those of the other antidiabetic drugs but were comparable with others previously reported. The developed method was applied to the first-time determination of the concentrations of the five antidiabetic drugs in wastewater, river water and tap water. Metformin was the antidiabetic drug at the highest concentration in wastewater and surface water (up to 253 ng L(-1) and 104 ng L(-1), respectively). Two of the antidiabetic drugs of recent prescription, sitagliptin and vildagliptin, were found in effluent wastewater at concentrations of 117 ng L(-1) and 12 ng L(-1), respectively, and in river water at concentrations of 35 ng L(-1) and 6 ng L(-1), respectively, whereas the classic antidiabetic drug glibenclamide and the novel drug pioglitazone were not detected.

[Systematic analysis of oral hypoglycemic agents in health foods].

A systematic analysis for 11 ingredients of oral hypoglycemic agent in health foods was established using three different analytical methods; i.e. thin-layer chromatography (TLC), high-performance liquid chromatography (HPLC) and comparison of MS/MS spectra analyzed by liquid chromatography/tandem mass spectrometry (LC/MS/MS). In Normal-phase and reversed-phase TLC, each condition to separate and detect 10 ingredients except nateglinide was developed. On the other hand, 11 ingredients were detected qualitatively and quantitatively by HPLC. The recovery rates were 92-101% and each coefficient of variation was less than 5.4%. Then UV spectra were monitored using this HPLC method and furthermore MS/MS spectra of 11 ingredients were obtained by LC/MS/MS. Identification of each ingredient became precise and rapid by comparing UV and MS/MS spectra of standard solutions with that of extract solutions from health foods. Using this systematic analysis, glibenclamide was accurately determined and identified from health foods.

Repeatability of monolithic HPLC columns while using a flow program.

Fast HPLC methods are becoming more and more important. Using monolithic HPLC columns for fast separations, a flow program can be applied for further decrease in the total run time. An interesting issue was whether the flow program affects repeatability. The investigated method was a generic assay for the oral antidiabetic drugs glibenclamide and glimepiride in the presence of two of their degradation products. A flow program ranging from 5.0 to 9.9 mL/min had been set up to decrease the run time to approximately 1.7 min. Within-day RSD% (n = 40) for both retention times and peak areas were less than 1%. At flow rates higher than 7 mL/min, repeatability was impaired to some extent. It became mainly noticeable through the day-to-day precision (n = 60) which showed RSD% up to 2%. However, further investigations indicated that this was rather related to pump inefficiency at high flow rates than to the flow program as such. Presuming the use of appropriate equipment, qualified for high flow rates, the application of a flow program for shortening the run time is absolutely reasonable and does not affect repeatability.

[Separation and determination of glibenclamide in xiaotangling tablets by micellar electrokinetic capillary chromatography].

A high performance capillary electrophoresis method has been developed for separation and quantitative analysis of glibenclamide in Xiaotangling tablets. Electrophoretic conditions were as follows: micellar electrokinetic capillary chromatography (MECC) mode, trimethoprimum as internal standard, uncoated fused silica capillary (34.8 cm/39.5 cm(effective/total length), 50 microns i.d.), 25 mmol/L borax-30 mmol/L SDS(pH 9.0), applied voltage 17 kV, (+)-->(-), temperature 28 degrees C, detection wavelength 228 nm, pressure injection 68.95 kPa.s. Glibenclamide was separated successfully from other components within 14 minutes under the optimum conditions, and the relative peak area of glibenclamide increased linearly with the increase of its concentration within the range of 25 mg/L-275 mg/L. The recovery was (100.6 +/- 1.4)%. The method is simple, rapid and well reproducible, and can be used as a reliable tool for the quality control of Chinese traditional medicine containing glibenclamide.