Shuang Shaomin

Preparation and spectral investigation on inclusion complex of β-cyclodextrin with rutin

Abstract Solid inclusion complex of rutin with β-cyclodextrin (β-CD) was prepared by coprecipitate method. The formation of inclusion complex was confirmed by differential scanning calorimetry (DSC) and X-ray diffraction. The formation constant was obtained by steady-state fluorescence measurements and the result suggested the complex preferred 1:1 (rutin:CD) stoichiometry. Furthermore, the spatial configuration of the complex has been proposed based on NMR and molecular modeling.

Study on molecular recognition of para-aminobenzoic acid species by α-, β- and hydroxypropyl-β-cyclodextrin

Abstract The molecular recognition interaction of α-cyclodextrin, β-cyclodextrin and hydroxypropyl-β-cyclodextrin by para-aminobenzoic acid (PABA) species was studied by using steady-state fluorescence measurements. PABA can exist as one of three species (an anionic, neutral on cationic species) due to its amphoteric property. The various factors affecting the inclusion process were examined in detail. The type of species depended on the pH value in the medium. The results suggested that cyclodextrins (CDs) were most suitable for inclusion of the uncharged species of PABA and could cause enhanced fluorescence emission of PABA. A mechanism is proposed to explain the inclusion process.

Study on inclusion interaction of piroxicam with β-cyclodextrin derivatives

Abstract The inclusion behavior of piroxicam (PX) with β-cyclodextrin (β-CD), hydroxypropyl-β-cyclodextrin (HP-β-CD), and carboxymethyl-β-cyclodextrin (CM-β-CD) was investigated by using steady-state fluorescence and nuclear magnetic resonance (NMR) technique. The various factors affecting the inclusion process were examined in detail. The remarkable fluorescence emission enhancement upon addition of CDs suggested that cyclodextrins (CDs) were most suitable for inclusion of the uncharged species of PX. The stoichiometry of the PX–CDs inclusion complexes was 1:1, except for β-CD where a 1:2 inclusion complex was formed. The formation constants showed the strongest inclusion capacity of β-CD. NMR showed the inclusion mode of PX with CDs.

Study on vitamin K3-cyclodextrin inclusion complex and analytical application.

The inclusion interaction of the complexes between Vitamin K(3) (VK(3)) and beta-cyclodextrin (beta-CD), hydroxypropyl-beta-cyclodextrin (HP-beta-CD) and sulfobutylether-beta-cyclodextrin (SBE-beta-CD) were studied by using steady-state fluorescence measurements. The various factors affecting the inclusion process were examined in detail. The formation constants and inclusion stoichiometry for VK(3)-CDs were determined. The results showed that the inclusion ability of beta-CD and its derivatives was the order: SBE-beta-CD>HP-beta-CD>beta-CD. The related inclusion mechanism is proposed to explain the inclusion process. A method of determining VK(3) was established with the linear range was 2.5 x 10(-6)-5.0 x 10(-4) M, and was used to determine the VK(3) tablets. The recoveries were in the range of 97.52-103.5%. The results were satisfactory.

Study on the paper substrate room temperature phosphorescence of theobromine, caffeine and theophylline and analytical application

Paper substrate room temperature phosphorescence (RTP) of theobromine (TB), caffeine (CF) and theophylline (TP) were investigated. The method is based on fast speed quantitative filter paper as substrate and KI-NaAc as heavy atom perturber. Various factors affecting their RTP were discussed in detail. Under the optimum experimental conditions, the linear dynamic range, limit of detection (LOD), and relative standard deviation (R.S.D.) were 14.41 approximately 576.54 ng per spot, 1.14 ng per spot, 4.8% for TB, 5.44 approximately 699.08 ng per spot, 0.78 ng per spot, 1.56% for CF, 7.21 approximately 360.34 ng per spot, 1.80 ng per spot, 3.80% for TP, respectively. The first analytical application for the determination of these compounds was developed. The recovery of standard samples added to commercial products chocolate, tea, coffee and aminophylline is in the range 92.80-106.08%. The proposed method was successfully applied to real sample analysis without separation.

Determination of thioguanine in pharmaceutical preparations by paper substrate room temperature phosphorimetry

A room temperature phosphorimetric (RTP) procedure was used for the determination of 6-thioguanine (6-TG). The method is based on paper substrate room temperature phosphorimetry (PS-RTP) using indium sulfate, In2(SO4)3 as a heavy atom perturber. Various factors affecting the room temperature phosphorescence of 6-TG are discussed. The linear dynamic range for 6-TG is from 3.3 to 334.3 ng per spot with a detection limit of 4.6 ng per spot and a relative standard deviation (RSD) of 2.38%. The recovery of standard 6-TG added to commercial tablets is in the range 96.39-98.44%. The method is simple, rapid and sensitive and can be applied to the analysis of commercial tablets without interference.

A NOVEL CHEMOSENSOR FOR Fe(III) BASED ON PHOSPHORESCENCE QUENCHED 9-BROMOPHENANTHRENE INDUCED BY β-CYCLODEXTRIN COMBINED WITH FLOW INJECTION RENEWABLE DROP

A novel phosphorescent chemosensor for Fe(III) based on room-temperature phosphorescence (RTP) using the method of flow injection renewable drop (FIRD) was developed. A RTP of 9-bromophenanthrene (BrP) can be induced by β-cyclodextrin (β-CD) in the presence of cyclohexane (CH); however, trace Fe(III) caused a decrease of the RTP emission. The optimal conditions were investigated. Under the optimal conditions, the analytical curve of Fe3+ gave a linear dynamic range of 4.0 × 10−7 mol(L−1∼6.0 × 10−4 mol(L−1, with a detection limit of 36 μg/L. When the established CD-RTP method was applied to determine the concentrations of Fe(III) in synthetic samples, the experiment results demonstrated that the range of recovery was 97.3%–102%, with a relative standard deviation less than 2.05% (n = 6).

Controlled Release of Curcumin via Folic Acid Conjugated Magnetic Drug Delivery System

In the paper, folic acid(FA)-mediated and β-cyclodextrin(β-CD) derivatives functionalized magnetic Fe3O4 nanoparticles(MNPs) were successfully prepared as drug carriers for the targeted delivery and controlled release of water-insoluble anticancer drug. FA-sulfobutyl ether-β-CD-MNPs(FA-SBE-β-CD-MNPs), FA-hydroxypropyl-β-CD-MNPs(FA-HP-β-CD-MNPs) and FA-carboxymethyl-β-CD-MNPs(FA-CM-β-CD-MNPs) were fabricated, and the loading efficiency and relative entrapment rate of curcumin are 12.04 mg/g, 95.56% for FA-SBE-β-CD-MNPs, 9.6 mg/g, 81.63% for FA-HP-β-CD-MNPs and 7.88 mg/g, 85.28% for FA-CM-β-CD-MNPs, respectively. Meanwhile, at pH=5.0, the optimal release rate of curcumin is about 46.07% for FA-SBE-β-CD-MNPs in 5 h. Cellular uptake indicates that curcumin can be selectively transported to targeting site and released from the internalized carriers. The in vitro cytotoxicity reveals that non-toxic FA-SBE-β-CD-MNPs have excellent biocompatibility on HepG2 cells in the tested concentrations. Therefore, FA-SBE-β-CD-MNPs could provide a promising platform for the targeting delivery of water insoluble anti-cancer drugs for different treatment needs of cancer therapy.

A novel highly sensitive fluorescent probe based on Schiff base for Al 3

A facile Schiff-base ligand 8-hydroxyjulolidine-pyridyl hydrazone ( L ) as the fluorescent probe was synthesized and characterized. L was selective toward Al3+ ions with a visible color change from pale-to-yellow and fluorescence enhancement at 480 nm. L forms complex with Al3+ in 1:1 ratio as supported by Job’s plot analysis and ESI-MS. The binding mode was further confirmed by 1H NMR titrations. The detection limit was calculated to be 8.22×10−8 M for Al3+. These merits of L , i.e., requiring facile one-step synthesis and displaying high sensitivity make L a promising candidate as a chemosensor for Al3+ion.