Eudragit S100 coated microsponges for Colon targeting of prednisolone

Context: Microsponge is a novel approach for targeting the drug to the colon for the management of colon ailments such as inflammatory bowel disease.

Objective: Prednisolone loaded microsponges (PLMs) were prepared and coated with Eudragit S 100 (ES) and evaluated for colon-specific drug delivery.

Materials and methods: PLMs were prepared using quasi emulsion solvent diffusion technique using ethyl cellulose, triethylcitrate (1% v/v, plasticizer) and polyvinyl alcohol (Mol. Wt. 72?kDa, emulsifying agent). The developed microsponges were compressed into tablets via direct compression technique using sodium carboxymethyl cellulose (Na CMC) and magnesium stearate as super-disintegrant and lubricant, respectively. The tablets were then coated with ES to provide protection against harsh gastric environment and manifest colon-specific drug release.

Results: PLMs were found to be nano-porous spherical microstructures with size around 35?µm and 86% drug encapsulation efficiency. Finally, they were compressed into tablets which were coated with Eudragit S 100 In vitro drug release from ES coated tablets was carried out at various simulated gastrointestinal fluids i.e. 1?hr in SGF (pH 1.2), 2 to 3?h in SIF (pH 4.6), 4–5?h in SIF (pH 6.8), and 6–24?h in SCF (pH 7.4) and the results showed the biphasic release pattern indicating prolonged release for about 24?h.

Discussion and conclusion: In vitro drug release studies revealed that drug starts releasing after 5?h by the time PLMs may enter into the proximal colon. Hence maximum amount of drug could be released in the colon that may result in reduction in dose and dose frequency as well as side effects of drug as observed with the conventional dosage form of prednisolone.     

QoS and resource management in distributed interactive multimedia environments

Quality of Service (QoS) is becoming an integral part of current ubiquitous Distributed Interactive Multimedia Environments (DIMEs) because of their high resource and real-time interactivity demands. It is highly influenced by the management techniques of available resources in these cyber-physical environments. We consider QoS and resource management influenced by two most important resources; the computing (CPU) and networking resources. In this paper, we survey existing DIME-relevant QoS and resource management techniques for these two resources, present their taxonomy, compare them, and show their impacts on DIMEs. Finally, we discuss appropriateness of those techniques in a sample DIME scenario.     

Interplay of spin,lattice, vibration,and charge degrees of freedom: Magneto-dielectricity in Ca3Mn2O7

From low-temperature Synchrotron X-ray diffraction, a precise thermal characterization of octahedral distortions in single-phase Ruddlesden-Popper Ca₃Mn₂O₇ is performed. Highly sensitive close-steps temperature dependences of Mn-O-Mn bond angles connecting MnO₆ octahedra clearly reveal the signature of spin ordering in the system. Spin-lattice coupling is thus revealed via the structural distortions, responsible for the evolution of the magnetic state. Further, benchmark temperature anomalies observed in the unit cell volume and its polarization-measure highlight the interplay between spin, lattice, and charge degrees of freedom. Strong spin-lattice coupling is supported by the Raman spectroscopy results across the magnetic ordering. Dielectric study on Ca₃Mn₂O₇ features relaxor-like segmented dynamics below the antiferromagnetic ordering. Dipolar relaxations of different origins are spectrally resolved, exhibiting distinct H-field alterations which identify their allegiance to different magnetic subphases. Dipole-relaxation characteristics examined under applied magnetic field and the ensuing magneto-dielectricity consistently correlate with the concurrent magnetic, structural, and vibrational features.     

Influence of Hydrogenation on Electronic and Magnetic Properties of PrNi: A First Principles Study

Electronic and magnetic properties of PrNi and PrNi–H have been investigated by using first principles approach. Calculations are performed using full potential linearized augmented plane wave plus local orbitals method including spin-polarization within the frame work of density functional theory. The electronic exchange–correlation energy is described by generalized gradient approximation. The ground state of both the compounds is base-centered orthorhombic CrB structure. The hydrogen stored in PrNi, i.e., PrNi–H has been studied to analyze the effective changes in magnetic moments and electronic structures in comparison with PrNi. The total cell energy of the hydrogenated PrNi compound has been found to be lower than in PrNi compound. The decrease in the cell energy shows more stability of the hydrogenated PrNi at ambient conditions. The values for total and local magnetic moments decrease on hydrogen insertion in PrNi. A comparative study of the projected density of states in both the compounds has also been presented. Both the compounds are found metallic in nature.     

High-responsivity (Ga2Ge)100−x(Ga3Sb2)x (x = 15, 30, 45, 60) photodetection sensor for optoelectronic applications

Journal of Materials Science: Materials in Electronics - Electromagnetic signal detection for applications such as astronomy, product quality monitoring, health, and necessitates systems that are...     

The Effect of Heat Treatment of TiO2 Nanoparticles on Photovoltaic Performance of Fabricated DSSCs

The present work focuses on the synthesis of mixed phase TiO₂ nanoparticles with reduced band gaps without even being doped. The synthesis was carried out by chemical route followed by heat treatments at different temperatures to favor rutile incorporation in anatase network. The significance of different heat treatment temperatures on the phase composition of TiO₂ nanoparticles and its effect on optical band gap and the photovoltaic performance are analyzed. The thermal analysis, phases, morphology, and energy band gap of as-synthesized TiO₂ nanoparticles have been characterized by DTA/TG, x-ray diffraction, field-emission scanning electron microscope, transmission electron microscope, and UV-Vis-NIR, respectively. The results show the presence of rutile (~15 nm) and anatase phases (~17 nm) in “as-synthesized” TiO₂ nanoparticles. TiO₂ nanoparticles are heat treated for 2 h at 200, 400, and 600 °C in air. It is observed that heat treatment results in higher photoactivity in visible region of the solar radiation and the material demonstrated high photovoltaic performance in conjunction with N-719. The optical band gap values are found to be in the range of 2.59-2.88 eV. The dye-sensitized solar cells (DSSCs) fabricated by TiO₂ nanoparticles, heat treated at 600 ºC show the energy conversion efficiency (η) of 6.08% with high photo current density (J _sc) of 11.76 mA/cm². The work highlighted in this paper represents the realization of simple method of achieving low band gap semiconductors without being doped, for DSSCs applications.     

Development of a Spectrophotometric Biphasic Assay for the Estimation of mPEG-maleimide in Thiol PEGylation Reaction Mixtures

Methoxy(polyethylene glycol)-maleimide (mPEG-mal) is a PEG derivative used for thiol PEGylation of protein molecules and finds application in drug delivery studies. The maleimide group undergoes degradation in aqueous media, resulting in the difficult quantitative analysis of mPEG-mal. Routinely employed methods for separation and estimation of mPEG-mal include tedious chromatographic methods like ion exchange, high-performance liquid chromatography with refractive index detector and techniques like mass spectrometry and proton nuclear magnetic resonance. We present a direct and reproducible spectrophotometric method to quantify free and protein bound mPEG-mal in thiol PEGylation reaction mixtures. This method is based on the partitioning of a PEG bound chromophore between an aqueous ammonium isoferrothiocyanate phase to a chloroform phase in the presence of mPEG-mal. Several important parameters influencing the partitioning and stability of the chromophore, volume ratios of liquid phases, ethylenediaminetetraacetic acid concentration in the reaction mixture, mixing time, and chlorinated solvents used for partitioning have been studied.     

Optimization of carboxylate-terminated poly(amidoamine) dendrimer-mediated cisplatin formulation

Cisplatin is mainly used in the treatment of ovarian, head and neck and testicular cancer. Poor solubility and non-specific interactions causes hurdles in the development of successful cisplatin formulation. There were few reports on poly(amidoamine) (PAMAM) dendrimer–cisplatin complexes for anticancer treatment. But the earlier research was mainly focused on therapeutic effect of PAMAM dendrimer–cisplatin complex, with less attention paid on the formulation development of these complexes. Objective of the present study is to optimize and validate the carboxylate-terminated, EDA core PAMAM dendrimer-based cisplatin formulation with respect to various variables such as dendrimer core, generation, drug entrapment, purification, yield, reproducibility, stability, storage and in-vitro release. Dendrimer–cisplatin complex was prepared by an efficient method which significantly increases the % platinum (Pt) content along with the product yield. Dendrimers showed reproducible (～27%) platinum loading by weight. Variation in core and generations does not produce significant change in the % Pt content. Percentage Pt content of dendrimeric formulation increases with increase in drug/dendrimer mole ratio. Formulation with low drug/dendrimer mole ratio showed delayed release compared to the higher drug/dendrimer mole ratio; these dendrimer formulations are stable in room temperature. In vitro release profiles of the stored dendrimer–cisplatin samples showed comparatively slow release of cisplatin, which may be due to formation of strong bond between cisplatin and dendrimer. This study will contribute to create a fine print for the formulation development of PAMAM dendrimer–cisplatin complexes.