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Zi L.,Key Laboratory of Drug Quality Control and Pharmacovigilance | Zi L.,China Pharmaceutical University | Huang Y.,Key Laboratory of Drug Quality Control and Pharmacovigilance | Huang Y.,China Pharmaceutical University | And 4 more authors.
Journal of Luminescence | Year: 2014

A novel sensing fluorescent probe based on the fluorescence quenching of the thioglycolic acid-capped CuInS2/ZnS quantum dots (CuInS 2/ZnS/TGA QDs) was established for cobalt ions detection. The fluorescence quenching of CuInS2/ZnS/TGA QDs was due to the increasing surface deficiency and the inner-filter effect, which were attributed to the reaction between Co2+ and sulfur bonds on the surface of QDs. The quenching curve could be fitted by a typical Stern-Volmer-type equation, with a linear relationship between the quenching efficiency and the concentration of cobalt ions in the range of 0.3012-90.36 μmol L -1. And the detection limit (S/N=3) for Co2+ was 0.16 μmol L-1. Therefore, the established probe provided a simple, rapid, cheap and sensitive method for Co2+ detection. In a word, this method can be used to detect Co2+ in the environment. © 2013 Elsevier B.V.


Hu W.,China Pharmaceutical University | Hu W.,Key Laboratory of Drug Quality Control and Pharmacovigilance | Hong T.,China Pharmaceutical University | Hong T.,Key Laboratory of Drug Quality Control and Pharmacovigilance | And 4 more authors.
TrAC - Trends in Analytical Chemistry | Year: 2014

Nanoparticles, novel materials with considerable potential in various applications, have made a significant contribution to the development of stationary phases in chromatography. In capillary electrochromatography (CEC), the process for creating stationary phases has a substantial effect on separation performance. Due to their extraordinary properties, nanoparticles (NPs) can generally improve the separation selectivity, the column efficiency and the chemical stability of CEC.This review focuses on the latest applications and achievements of immobilizing NPs in stationary phases for CEC. For each type of NP, we describe different immobilization strategies, including physical adsorption on surfaces, covalent bonding and other methods. Also, we present more practical applications based on functional post-modifications of the stationary phase containing NPs. Further, we discuss potential directions and issues worth exploring for novel stationary phases containing NPs. © 2014 Elsevier B.V.


Jiang Y.,China Pharmaceutical University | Yan F.,China Pharmaceutical University | Di B.,China Pharmaceutical University | Di B.,Key Laboratory of Drug Quality Control and Pharmacovigilance | And 4 more authors.
Journal of Pharmaceutical and Biomedical Analysis | Year: 2011

A novel, sensitive and rapid liquid chromatographic-electrospray ionization mass spectrometric method was developed and validated for the determination of zofenopril and its active metabolite zofenoprilat in human plasma. The method was based on a single extraction step using methyl tert-butyl ether and did not require chemical derivatization. The chromatographic conditions were optimized; separation was performed on a phenyl-hexyl column (5 μm, 250 mm ×4.6 mm i.d) with a mobile phase consisting of a solution of methanol and water (95:5, v/v) that also contained 0.1% of formic acid. A flow rate of 1.0. mL/min was used. Zofenopril, zofenoprilat and the internal standard (IS) fosinopril sodium were measured using an electrospray ion source in a positive reaction monitoring mode. Linear calibration curves were generated for zofenopril concentrations between 0.1052 and 1052 ng/mL and for zofenoprilat concentrations between 0.2508 and 2508 ng/mL. In both cases, the coefficients of determination were greater than 0.995. The extraction recovery for zofenopril was 93.5% on average. It was 92.5% for zofenoprilat. The inter- and intra-batch precision and accuracy for both zofenopril and zofenoprilat were higher than 14%. The method was applied to measure the concentrations of zofenopril and zofenoprilat in plasma samples. © 2011 Elsevier B.V.


Hong T.,China Pharmaceutical University | Hong T.,Key Laboratory of Drug Quality Control and Pharmacovigilance | Chi C.,China Pharmaceutical University | Chi C.,Key Laboratory of Drug Quality Control and Pharmacovigilance | And 2 more authors.
Journal of Separation Science | Year: 2014

Pepsin-modified affinity monolithic capillary electrochromatography, a novel microanalysis system, was developed by the covalent bonding of pepsin on silica monolith. The column was successfully applied in the chiral separation of (±)-nefopam. Furthermore, the electrochromatographic performance of the pepsin-functionalized monolith for enantiomeric analysis was evaluated in terms of protein content, pH of running buffer, sample volume, buffer concentration, applied voltage, and capillary temperature. The relative standard deviation (%RSD) values of retention time (intraday <0.53, n = 10; interday <0.53, n = 10; column-to-column <0.70, n = 20; and batch-to-batch <0.80, n = 20) indicated satisfactory stability of these columns. No appreciable change was observed in retention and resolution for chiral recognition of (±)-nefopam in 50 days with 100 injections. The proteolytic activity of this stationary phase was further characterized with bovine serum albumin as substrate for online protein digestion. As for monolithic immobilized enzyme reactor, successive protein injections confirmed both the operational stability and ability to reuse the bioreactor for at least 20 digestions. It implied that the affinity monolith used in this research opens a new path of exploring particularly versatile class of enzymes to develop enzyme-modified affinity capillary monolith for enantioseparation. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA.


Wu S.-M.,China Pharmaceutical University | Wu S.-M.,Key Laboratory of Drug Quality Control and Pharmacovigilance | Chen J.,China Pharmaceutical University | Chen J.,Key Laboratory of Drug Quality Control and Pharmacovigilance | And 4 more authors.
Journal of Pharmaceutical and Biomedical Analysis | Year: 2013

Based on outstanding optical properties of quantum dots (QDs), a rapid and specific method was established to determine Escherichia coli (E. coli) in drugs. Rabbit anti-goat antibody was covalently conjugated to water-soluble ZnS/CdSe QDs via a cross-linking reaction and the formed conjugate was named as IgG-QDs. The bio-fluorescent probe was verified using agarose gel electrophoresis. Attributing to the affinity between goat anti-E. coli antibody and rabbit anti-goat antibody, E. coli was bio-labeled by IgG-QDs successfully, which was then contributed to detecting E. coli in drugs specifically. The results demonstrated that bioactivity and biorecognition of the antibody was not influenced by the conjugation reaction and IgG-QDs could recognize E. coli specifically. Cell recovery rates for E. coli in clomipramine hydrochloride were 82.90% and 73.64%, respectively. The entire detecting process only spent less than 4. h. The method was proved to be rapid and specific, and it could be used to detect stressed and injured cells. © 2013 Elsevier B.V.


Liu M.,Key Laboratory of Drug Quality Control and Pharmacovigilance | Liu M.,China Pharmaceutical University | Zheng Y.,Key Laboratory of Drug Quality Control and Pharmacovigilance | Zheng Y.,China Pharmaceutical University | And 3 more authors.
Journal of Pharmaceutical and Biomedical Analysis | Year: 2011

A selective capillary electrophoresis method for determination of enantiomeric purity of RS86017, a new antiarrhythmic agent with two chiral centers, was developed and validated using sulfobutyl ether-β-cyclodextrin as chiral selector. The concentration of the chiral selector and organic modifier, pH of background electrolyte (BGE), capillary temperature, and applied voltage were systematically optimized by using orthogonal design and concentration of chiral selector was further optimized. The optimal conditions included 25. mM phosphate buffer at pH 8.0, containing 28. mg/mL sulfobutyl ether-β-cyclodextrin and 20% acetonitrile as running buffer, an applied voltage of 22. kV, and a temperature of 20 °C. The detection wavelength was 206. nm. The obtained method was capable of separating RS86017 from its potential chiral impurities, the S,R-enantiomer, the R,R-diastereomer and the S,S-diastereomer with a short analysis time of 10. min. The separation was validated with respect to its selectivity, repeatability, linearity, precision, accuracy, limits of detection (LOD), limits of quantitation (LOQ) and robustness testing. The LODs and LOQs were 0.8 μg/mL and 2.5 μg/mL for all isomers of RS86017, respectively. Finally, the method was used to investigate the chiral purity of RS86017 in bulk samples. © 2011 Elsevier B.V.


Liu Y.,Key Laboratory of Drug Quality Control and Pharmacovigilance | Liu Y.,China Pharmaceutical University | Chen L.,Key Laboratory of Drug Quality Control and Pharmacovigilance | Chen L.,China Pharmaceutical University | And 2 more authors.
Journal of Pharmaceutical and Biomedical Analysis | Year: 2013

Seven impurities in agomelatine drug substance were determined by a newly developed RP-HPLC method. Structures of potential impurities were confirmed by NMR and IR analysis. Efficient chromatographic separation was achieved on Hypersil BDS C18 column (250mm×4.6mm, 5μm) in gradient mode by using a binary mixture of potassium dihydrogen phosphate (15mM, pH adjusted to 3.0) and acetonitrile at a flow rate of 1.0ml/min. A photodiode array detector set at 230nm was used for detection. Forced degradation studies showed that the proposed method was specific, and agomelatine was found to be susceptible to acidic and alkaline conditions. The method was validated according to ICH guidelines with respect to specificity, sensitivity, precision, linearity, accuracy, robustness and system suitability. Detection limit of impurities was in the range of 0.0008-0.0047%. Regression analysis showed correlation coefficient value greater than 0.999 for agomelatine and its seven impurities. Accuracy of the method was established based on the recovery obtained between 94.4% and 106.7% for all impurities. The validation results demonstrated that the developed method was suitable for the quantitative determination of potential impurities in agomelatine. A possible mechanism for the formation of impurities was proposed. © 2013 Elsevier B.V.


Fan X.-M.,Key Laboratory of Drug Quality Control and Pharmacovigilance | Fan X.-M.,China Pharmaceutical University | Ji Y.-B.,Key Laboratory of Drug Quality Control and Pharmacovigilance | Ji Y.-B.,China Pharmaceutical University | Zhu D.-N.,China Pharmaceutical University
Chromatographia | Year: 2010

An integrated strategy based on experimental designs for the development, optimization and validation of the fingerprint method of Sheng-Mai-San by MEKC has been described. Orthogonal and sequential uniform designs were employed to select important experimental parameters and optimize CE conditions. Method validation was performed in terms of injection precision, sample stability test and robustness testing. Additionally, conventional modeling method was used to predict the optimum separation conditions for comparative purpose. The strategy described can also be utilized for fingerprint development in the quality control of other herbal medicines. © 2010 Vieweg+Teubner Verlag | Springer Fachmedien Wiesbaden GmbH.


Hong T.,Key Laboratory of Drug Quality Control and Pharmacovigilance | Zheng Y.,Key Laboratory of Drug Quality Control and Pharmacovigilance | Hu W.,Key Laboratory of Drug Quality Control and Pharmacovigilance | Ji Y.,China Pharmaceutical University
Analytical Biochemistry | Year: 2014

A system of capillary silica monolith with bovine serum albumin (BSA) functionalized through two approaches for affinity monolithic capillary electrochromatography (AMCEC) was developed. Covalent immobilization conditions for two different Schiff base methods, which employed 3-glycidopropyl trimethoxysilane (GPTS) and 3-aminopropyl trimethoxysilane (APTS) as starting materials, respectively, were investigated to obtain good and stable chiral separation. The BSA immobilized silica monoliths were evaluated in terms of morphology, electroosmotic flow, retention time, column efficiency and resolution of model compound (±)-tryptophan. The columns exhibited satisfactory run-to-run, column-to-column repeatability and maintained their enantioselectivity for more than 3 months. Both developed methods can baseline separate tryptophan enantiomers, whereas shorter retention time, better column efficiency, and enantiomeric recognition between two pairs of drug enantiomers (pantoprazole and atenolol) were obtained by the GPTS method. © 2014 Elsevier Inc. All rights reserved.


Ye C.,Key laboratory of Drug Quality Control and Pharmacovigilance | Ye C.,China Pharmaceutical University | Wang Y.,Key laboratory of Drug Quality Control and Pharmacovigilance | Wang Y.,China Pharmaceutical University | And 6 more authors.
Microchimica Acta | Year: 2013

We report on a simple, fast and convenient method to engineer lipid vesicles loaded with quantum dots (QDs) by incorporating QDs into a vesicle-type of lipid bilayer using a phase transfer reagent. Hydrophilic CdTe QDs and near-infrared (NIR) QDs of type CdHgTe were incorporated into liposomes by transferring the QDs from an aqueous solution into chloroform by addition of a surfactant. The QD-loaded liposomes display bright fluorescence, and the incorporation of the QDs into the lipid bilayer leads to enhanced storage stability and reduced sensitivity to UV irradiation. The liposomes containing the QD were applied to label living cells and to image mouse tissue in-vivo using a confocal laser scanning microscope, while NIR images of mouse tissue were acquired with an NIR fluorescence imaging system. We also report on the fluorescence resonance energy transfer (FRET) that occurs between the CdTe QDs (the donor) and the CdHgTe QDs (the acceptor), both contained in liposomes. Based on these data, this NIR FRET system shows promise as a tool that may be used to study the release of drug-loaded liposomes and their in vivo distribution. © 2012 Springer-Verlag Wien.

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