Preparation, characterization, and in vivo evaluation of a polymorphic form of valnemulin hydrogen tartrate

We prepared a polymorphic form of valnemulin hydrogen tartrate (Form I) to overcome the instability and irritating odor of valnemulin hydrochloride that affect its use in the production and application of veterinary drugs. The physicochemical properties of Form I were characterized by scanning electron microscopy, X-ray powder diffraction, infrared spectroscopy, differential scanning calorimetry, and thermogravimetric analysis. The results showed the crystal structure and thermal properties of Form I were very different from those of a commercially available form of valnemulin hydrogen tartrate (Form II). Form I and Form II were more stable than valnemulin hydrochloride after storage under irradiation and high humidity conditions, respectively. The solubility of Form I was 2.6 times that of Form II, and Form I was selected for use in pharmaceutical kinetics experiments in vivo. Compared to valnemulin hydrochloride, after oral administration at a dose of 10 mg/kg in pigs, Form I had similar pharmaceutical kinetic behavior but a slightly higher area under the concentration–time curve from time zero to the last measurable concentration. Consequently, Form I should be suitable for the development of simple formulations and be effective in the clinical application of veterinary drugs.

Synthesis and anti-myocarditis activity in a multifunctional lanthanide microporous metal-organic framework with 1D helical chain building units

A new microporous lanthanide metal-organic framework, {[Yb(BTB)(H2O) (DEF)2}n (1, DEF=N,N-Diethylformamide), with 1D nano-sized channels has been constructed by bridging helical chain secondary building units with 1,3,5-benzenetrisbenzoic acid (H3BTB) ligand. Structural characterization suggests that this complex crystallizes in the hexagonal space group P6122 and possesses 1D triangular channels with coordinated water molecules pointing to the channel center. In addition, anti-myocarditis properties of compound 1 were evaluated in vivo. The results showed that compound 1 can improve hemodynamic parameters of, and it may be a good therapeutic option for heart failure in the future.

Interfacial modulus mapping of layered dental ceramics using nanoindentation

PURPOSE: The aim of this study was to test the modulus of elasticity (E) across the interfaces of yttria stabilized zirconia (YTZP) / veneer multilayers using nanoindentation. MATERIALS AND METHODS: YTZP core material (KaVo-Everest, Germany) specimens were either coated with a liner (IPS e.max ZirLiner, Ivoclar-Vivadent) (Type-1) or left as-sintered (Type-2) and subsequently veneered with a pressable glass-ceramic (IPS e.max ZirPress, Ivoclar-Vivadent). A 5 µm (nominal tip diameter) spherical indenter was used with a UMIS CSIRO 2000 (ASI, Canberra, Australia) nanoindenter system to test E across the exposed and polished interfaces of both specimen types. The multiple point load – partial unload method was used for E determination. All materials used were characterized using Scanning Electron Microscopy (SEM) and X – ray powder diffraction (XRD). E mappings of the areas tested were produced from the nanoindentation data. RESULTS: A significantly (P<.05) lower E value between Type-1 and Type-2 specimens at a distance of 40 µm in the veneer material was associated with the liner. XRD and SEM characterization of the zirconia sample showed a fine grained bulk tetragonal phase. IPS e-max ZirPress and IPS e-max ZirLiner materials were characterized as amorphous. CONCLUSION: The liner between the YTZP core and the heat pressed veneer may act as a weak link in this dental multilayer due to its significantly (P<.05) lower E. The present study has shown nanoindentation using spherical indentation and the multiple point load - partial unload method to be reliable predictors of E and useful evaluation tools for layered dental ceramic interfaces.

Preparation and release behaviour of mesoporous silica/ethylcellulose sustained-release mini-matrix / 药学学报

Hot-melt extrusion was applied to prepare mesoporous silica/ethylcellulose mini-matrix for sustained release, and fenofibrate was used as a model drug, ethylcellulose and xanthan gum were chosen as sustained-release agent and releasing moderator, respectively. This novel matrix obtained the controlled release ability by combining mesoporous silica drug delivery system and hot-melt extrusion technology. And mesoporous silica particle (SBA-15) was chosen as drug carrier to increase the dissolution rate of fenofibrate in this martix. Scanning electron microscope, transmission electron microscope, small angle X-ray powder diffraction and N2 adsorption-desorption were introduced to determine the particle morphology, particle size and pore structure of the synthesized SBA-15. The results showed that SBA-15 had a very high Brunauer-Emmett-Teller specific surface area, a narrow pore size distribution, large pore volume and a ordered two-dimensional hexagonal structure of p6mm symmetry. Differential scanning calorimetry and X-ray powder diffraction results demonstrated that fenofibrate dispersed in an amorphous state inside the pores of the mesoporous silica which contributed to the improvement in the dissolution rate. The drug release of mini-matrices was influenced by ethylcellulose viscosity grades and xanthan gum concentration, which increased with the increasing of xanthan gum concentration and decreasing of ethylcellulose viscosity. Mini-matrix containing 22% xanthan gum exhibited a good sustained release performance, and the drug release behavior followed the first-order kinetics.

Fabrication of potential macromolecular prodrugs of aspirin and diclofenac with dextran

Aspirin and diclofenac conjugates with dextran were synthesized as potential macromolecular prodrugs under homogeneous reaction conditions by using 4-methyl-benzenesulfonyl chloride as an acylating agent in the presence of triethylamine as a base. Highly pure conjugates with good yields were synthesized by this acylation method. All of the products were found soluble in aqueous medium as well as in dimethylsulfoxide and N, N-dimethylacetamide. The UV/Vis spectrophotometry has indicated the incorporation of drugs in conjugates and extent of substitution of drug onto dextran polymer. Covalent attachment of the drug onto the drug carrier polymer [dextran] was verified by [1]H NMR and Fourier transform infrared [FTIR] spectroscopic analysis. The prodrugs were analysed by powder X-ray diffraction [XRD] measurements. Phase changes were noticed by powder XRD for all macromolecular prodrugs indicating the change of state of matter towards more crystallinity. Therefore, fabricated macromolecular prodrugs are potential candidates to show better pharmacokinetic profile. All of the products were thoroughly characterized by using different spectroscopic techniques

Kinetic study on dissociation of amylose/salicylic acid compound using non-isothermal method / 药学学报

The inclusion compound of amylose and salicylic acid (SA) was prepared by a sealed temperature control method, and the formation of the inclusion compound was confirmed by IR spectrum and powder X-ray diffraction. The kinetic parameters of dissociation of amylose/SA compound were studied by the nonisothermal method which was defined as a relationship between the dissociation ratio and time. The values of activation energy (Ea) and frequency factors (InA) were calculated by a nonlinear least-square method. In this study, the formation of the inclusion compound of amylose/SA was confirmed by IR spectrum powder X-ray diffraction. SA existed in a molecule form in the spiral stouction of amylose. The dissociation of amylose/SA compound was attributed to first order reaction. The values of Ea calculated by the nor-isothermal method were 21.71 and 22.41 kJ x mol(-1) at heating rate 5 and 10 degrees C x h(-1), respectively. The corresponding isothermal method value of Ea was 22.17 kJ x mol(-1); the calculated InA values were 9.32 and 10.08 at heating rate 5 and 10 degrees C x h(-1), respectively. The corresponding isothermal method lnA value was 9.26. The results were in good agreement with Ea values and lnA values by isothermal method. These results indicated that the non-isothermal method described in this study could be adequately used for the stability study of inclusion compound and was a rapid and accurate method for the determination of kinetic parameters.

Combined analysis of urinary stones by X-ray photoelectron spectroscopy and X-ray powder diffraction / 中国医学科学院学报

<p><b>OBJECTIVE</b>To seek the methods in the prevention and cure of urinary stones in the Zhujiang valley in Guangdong province.</p><p><b>METHODS</b>Twenty random urinary stones were quantitatively and morphologically analyzed by X-ray photoelectron spectroscopy (XPS) and X-ray powder diffraction (XRD).</p><p><b>RESULTS</b>Calcium oxalate (about 70%) was the main composition of urinary stones in the Zhujiang valley in Guangdong province; while 30% of which was uric acid stones. Most calcium oxalate stones contain phosphate; however, its content usually was less than 10%.</p><p><b>CONCLUSIONS</b>Calcium oxalate, uric acid and phosphate are the main compositions of urinary stones in the Zhujiang valley in Guangdong province. The compositions and phases of urinary stones can be obtained accurately by the combination of XPS and XRD.</p>