S. Wartewig and R. H. H. Neubert, Pharmaceutical applications of Mid-IR and Raman spectroscopy, Adv. Drug Del. Rev. 57 (2005) 1144--1170; DOI: 10.1016/j.addr.2005.01.022.
T. D. Wilson, Pentazocine , in Analytical Profiles of Drug Substance (Ed. K. Florey), Vol. 13, Pharmaceutical Press, London 1984, pp. 361--416.
R. K. Verma and S. Garg, Compatibility studies between isosorbide mononitrate and selected excipients used in the development of extended release formulations, J. Pharm. Biomed. Anal. 35 (2004
The aim of the study was to prepare site specific drug delivery of naproxen sodium using sodium alginate and Eudragit S-100 as a mucoadhesive and pH-sensitive polymer, respectively. Core microspheres of alginate were prepared by a modified emulsification method followed by cross-linking with CaCl2, which was further coated with the pH dependent polymer Eudragit S-100 (2.5 or 5 %) to prevent drug release in the upper gastrointestinal environment. Microspheres were characterized by FT-IR spectroscopy, X-ray diffraction, differential scanning calorimetry and evaluated by scanning electron microscopy, particle size analysis, drug loading efficiency, in vitro mucoadhesive time study and in vitro drug release study in different simulated gastric fluids. Stability studies of the optimized formulation were carried out for 6 months. SEM images revealed that the surface morphology was rough and smooth for core and coated microspheres, respectively. Core microspheres showed better mucoadhesion compared to coated microspheres when applied to the mucosal surface of freshly excised goat colon. The optimized batch of core microspheres and coated microspheres exhibited 98.42 ± 0.96 and 95.58 ± 0.74 % drug release, respectively. Drug release from all sodium alginate microsphere formulations followed Higuchi kinetics. Moreover, drug release from Eudragit S-100 coated microspheres followed the Korsmeyer-Peppas equation with a Fickian kinetics mechanism. Stability study suggested that the degradation rate constant of microspheres was minimal, indicating 2 years shelf life of the formulation.
Hydroxyl-containing fluoroacrylate copolymers with different fluorine and hydroxyl concentrations were synthesized via free-radical solution polymerization. Transparent fluorinated polyurethane (FPU) films were prepared by curing the copolymers with HDI (hexamethylene diisocyanate) trimer. The Fourier transform infrared spectroscopy (FT-IR) results revealed introduction of fluorine both into the copolymer and polyurethane. X-ray photoelectron spectroscopy (XPS) analyses indicated that a gradient concentration of fluorine existed in the depth profile of the fluorinated polyurethane films. The highest contact angle (CA) was obtained for the FPU film with fluoroacrylate monomer concentration of 22 wt.% because of fluorine present on the film surface. The surface topographies detected by SEM and AFM indicated that surface roughness contributed little to the film hydrophobicity. By increasing the fluoroacrylate monomer concentration, the decreasing of crosslinking degree of hard segment resulted in lowering the first degradation temperature, while more C-F groups in soft segment led to higher second degradation temperature. UV-Vis spectrophotometer measurements indicated that the FPU film with the fluoroacrylate monomer concentration of 16 wt.% still had a high transmittance of more than 90 % in the whole visible wavelength range.
In this study, the Taguchi method of design of experiment (DOE) was used to optimize the hydroxyapatite (HA) coatings on various metallic substrates deposited by sol-gel dip-coating technique. The experimental design consisted of five factors including substrate material (A), surface preparation of substrate (B), dipping/withdrawal speed (C), number of layers (D), and calcination temperature (E) with three levels of each factor. An orthogonal array of L18 type with mixed levels of the control factors was utilized. The image processing of the micrographs of the coatings was conducted to determine the percentage of coated area (PCA). Chemical and phase composition of HA coatings were studied by XRD, FT-IR, SEM, and EDS techniques. The analysis of variance (ANOVA) indicated that the PCA of HA coatings was significantly affected by the calcination temperature. The optimum conditions from signal-to-noise (S/N) ratio analysis were A: pure Ti, B: polishing and etching for 24 h, C: 50 cm min−1, D: 1, and E: 300 °C. In the confirmation experiment using the optimum conditions, the HA coating with high PCA of 98.5 % was obtained.
In this paper, 3-(triethoxysilyl)-propyl isocyanate (abbreviated as TESPIC) was modified by ethylparaben (EPB) to produce corresponding organic-inorganic monomers (EPB-TESPIC) with two components equipped with covalent bonds, which not only can coordinate to RE ions (Tb3+ and Eu3+) but also act as a sol-gel precursor. Luminescent hybrid materials consisting of terbium-europium complex, covalently bonded to silica-based network, have been obtained in situ via a sol-gel approach. Proton nuclear magnetic resonance spectroscopy (1HNMR) and Fourier transform infrared spectroscopy (FT-IR) were applied to characterize the structure of EPB-TESPIC. UV-visible, phosphorescence, and luminescence spectra were obtained to characterize the photophysical properties of the obtained hybrid material. Through co-hydrolysis and polycondensation, Tb3+ and Eu3+ can be introduced into the same organic-inorganic hybrid monomer, forming Si-O backbones. The experimental results show that the strong luminescence of rare-earth ions substantiates the optimum energy match and effective intramolecular energy transfer between the triplet state energy of coordination complex and the emissive energy level of the rare-earth ions. The hybrid material systems are expected to have potential applications in photophysical sensors.
Nadarajan Viju, Nagarajan Ezhilraj, Chellamnadar Vaikundavasagom Sunjaiy Shankar, Stanislaus Mary Josephine Punitha and Sathianeson Satheesh
Bacteria associated with surfaces have been frequently cited as a potential source for the isolation of bioactive metabolites. In this study, bacteria associated with marine gastropod, Babylonia sp. were isolated and screened for antibacterial activity against biofilm-forming bacteria. The antibiofilm and antifouling effect of the selected surface- associated bacterial strains were examined under in vitro and in vivo conditions. Results showed that the extracellular polymeric substances (EPS) of the bacterial strain CML associated with gastropod species considerably reduced the adhesion of biofilm-forming bacteria on glass coupons. Besides, the antifouling coat prepared by incorporating of this EPS into polyurethane varnish prevented the settlement of biofoulers on test substratum submerged in marine waters. The functional groups present in the EPS were analyzed using FT-IR. The bacterium responsible for the production of the bioactive EPS was identified as Bacillus subtilis subsp. by 16S rRNA gene sequencing. More detailed characterization of the identified bioactive EPS could lead to the isolation of a novel natural antifouling product.
Nasrul Haque Mia, Sardar Masud Rana, Firoz Pervez, Mohammad Reefaz Rahman, Khalid Hossain, Abdul Al Mortuza, Mohammad Khairul Basher and Mahbubul Hoq
Zinc oxide thin films with different thicknesses were prepared on microscopic glass slides by sol-gel spin coating method, then hydrothermal process was applied to produce zinc oxide nanorod arrays. The nanorod thin films were characterized by various spectroscopic methods of analysis. From the images of field emission scanning electron microscope (FESEM), it was observed that for the film thickness up to 200 nm the formed nanorods with wurtzite hexagonal structure were uniformly distributed over the entire surface substrate. From X-ray diffraction analysis it was revealed that the thin films had good polycrystalline nature with highly preferred c-axis orientation along (0 0 2) plane. The optical characterization done by UV-Vis spectrometer showed that all the films had high transparency of 83 % to 96 % in the visible region and sharp cut off at ultraviolet region of electromagnetic spectrum. The band gap of the films decreased as their thickness increased. Energy dispersive X-ray spectroscopy (EDS) showed the presence of zinc and oxygen elements in the films and Fourier transform infrared spectroscopy (FT-IR) revealed the chemical composition of ZnO in the film.
Maria Arshad, Abbas Khan, Zahoor H. Farooqi, Muhammad Usman, M. Abdul Waseem, Sayyar Ali Shah and Momin Khan
Due to their potential application in various fields of science and technology, the eco-friendly bio-synthesis of silver (Ag) nanoparticles (NPs) is a growing area for researchers. In this study, we report the green synthesis of Ag nanoparticles and their characterization by using various techniques. For the preparation of Ag particles, aqueous plant extract of ailanthus altissima was used as a reducing medium for Ag+ ions of silver nitrate to Ag0. UV-Vis spectrophotometry was used to trace the formation of Ag particles by noting their surface plasmon resonance peaks (400 nm to 440 nm). Fourier transform infrared spectroscopy (FT-IR) was employed to reveal the chemical composition of Ag nanoparticles which were capped by plant extract. Scanning electron microscopy (SEM) was used to get the lattice image, morphology and average size of Ag particles. The average size distribution of Ag NPs dispersed in aqueous media was also measured using dynamic light scattering (DLS). It was found that DLS results are in good agreement with those obtained from SEM. The synthesized particles were then subjected to the antibacterial and antifungal activities by studying them against various species, such as bacillus cereus, staphylococcus aureus, pseudomonas aeruginosa, E. coli and A. parasiticus, A. niger and A. flavus fungi. It was noted from the growth curves of both bacteria and fungi that in the presence of silver nanoparticles they show more in-zone growth as compared to the plant extract.
Puyou Jia, Meng Zhang, Caiying Bo, Lihong Hu and Yonghong Zhou
Poly(vinyl alcohol) films were prepared with manganous chloride (MnCl2 · 4H2O) and glycerin as complex plasticizer. The micro morphology of pure PVA film and complex plasticizer plasticized PVA films was observed by scanning electron microscope (SEM). The interaction between complex plasticizer and PVA molecules was investigated by Fourier transform infrared spectroscopy (FT-IR). The influence of complex plasticizer on crystalline, thermal and mechanical properties of PVA films was studied by X-ray diffraction (XRD), differential scanning calorimetry (DSC), thermogravimetric analysis (TG), and tensile testing, respectively. The results showed that the complex plasticizer of MnCl2 · 4H2O/glycerin could interacted with PVA molecular and then effectively destroy the crystals of PVA. PVA films plasticized with complex plasticizer of MnCl2 · 4H2O/glycerin became soft and ductile, with lower tensile strength and higher elongation at break compared with PVA films. This is an important cause of plasticization of the complex plasticizer of MnCl2 · 4H2O/glycerin on PVA films.
Ali N. Siyal, Saima Q. Memon, Mahar Amanullah, Tajnees Pirzada, Sajida Parveen and Naveed A. Sodho
In the present study, jamun seed waste has been explored for the removal of Pb(II) ions from aqueous solution. The multi-variant sorption optimization was achieved by the factorial design approach. 99.91% of Pb(II) ions was removed from aqueous solution. The results predicted by the model were in good agreement with the experimental results (the values of R2 and R2adj. were found to be 99.89% and 99.95%, respectively). Langmuir and D-R isotherm studies were carried out to find adsorbent’s capacities (183.9 ± 0.31 mg/g and 184.5 ± 0.16 mg/g respectively), sorption free energy 13.17 ± 0.16 and RL values in the range of 0.05-0.77, suggested the favorable chemical and/or ion exchange nature of the sorption process. The FT-IR study was carried out for unloaded and Pb(II) ions loaded jamun seed, indicated, Pb(II) ions associated with nitrogen and oxygen of jamun seed containing moieties during the adsorption process. The proposed method was successfully validated and applied for the treatment of Pb(II) ions contaminating drinking water.