Synthesis and Characterisation of Monolacunary Keggin Monovanado-deca-tungstophosphate and Its Complexes with Transition Metal Cations.

Five new complexes with metal cations (Mn2+, Fe3+, Co2+, Ni2+, and Cu2+) of monolacunary Keggin monovanado-deca-tungstophosphate, K8[PVW10O39]·15H2O, have been synthesised. The molar ratio of the combination between metal cations and K8[PVW10O39]·15H2O has been established to be 1:1, and its general molecular formulas were found to be: Kn[MPVW10O39(H2O)]·xH2O (n = 5 for M = Fe3+ and n = 6 for M = Mn2+, Co2+, Ni2+, and Cu2+). Optimal conditions for complexes' synthesis (pH, temperature, and reaction time) have been determined. The characterisation of K8[PVW10O39]·15H2O and of its compounds Kn[MPVW10O39(H2O)]·xH2O have been performed using AAS, TG-DTA-DTG, UV-VIS, IR, Raman, and powder XRD methods. In UV spectra, two maximums of absorption were obtained, at 200 and 250 nm, characteristic of Keggin polycondensate compounds. The coordination of cations Ni2+, Co2+, and Cu2+ through oxygen atoms from K8[PVW10O39]·15H2O in an octahedron system has been reflected with VIS spectroscopy. All these methods have proved the compositions and structures of K8[PVW10O39]·15H2O and Kn[MPVW10O39(H2O)]·xH2O, their similarity with other vanadotungstophosphates, and their achievements in the Keggin class. Additionally, all analysis methods have shown an increase in the degree of structural symmetry and the thermal stability of a polyoxoanion complex after attaching metal cations compared to the monolacunary, K8[PVW10O39]·15H2O.

A Review: Uses of Chitosan in Pharmaceutical Forms.

Chitosan is a natural polysaccharide widespread in nature. It has many unique and attractive properties for the pharmaceutical field: it is biodegradable, safe, hypoallergenic, biocompatible with the body, free of toxicity, with proven anticholesterolemic, antibacterial, and antimycotic action. In this review we highlighted the physical, chemical, mechanical, mucoadhesive, etc. properties of chitosan to be taken into account when obtaining various pharmaceutical forms. The methods by which the pharmaceutical forms based on chitosan are obtained are very extensive, and in this study only the most common ones were presented.

Preparation and Characterization of Chitosan-Alginate Microspheres Loaded with Quercetin.

The aim of this paper was to formulate microspheres based on biodegradable polymers (chitosan and sodium alginate), using the complex coacervation technique. Subsequently, the prepared microspheres were loaded with quercetin (QUE), a pharmacological active ingredient insoluble in water and unstable to light, temperature and air. After preparation, the loaded microspheres underwent several studies for physical chemical characterization (performed by scanning electron microscopy-SEM, laser 3D scanning, and thermal analysis-TA). Furthermore, they were analyzed in order to obtain information regarding swelling index, drug entrapment, and in vitro release capacity. The obtained experimental data demonstrated 86.07% entrapment of QUE into the microspheres, in the case of the one with the highest Ch concentration. Additionally, it was proved that such systems allow the controlled release of the active drug over 24 h at the intestinal level. SEM micrographs proved that the prepared microspheres have a wrinkled surface, with compact structures and a large number of folds. On the basis of the TA analysis, it was concluded that the obtained microspheres were thermally stable, facilitating their usage at normal physiological temperatures as drug delivery systems.

A review: Evolution of enzymatic biofuel cells.

Ever-growing demands for energy, the unsustainability of fossil fuel due to its scarcity and massive impact on global economies and the environment, have encouraged the research on alternative power sources to work upon for the governments, companies, and scientists across the world. Enzymatic biofuel cells (eBFCs) is one category of fuel cell that can harvest energy from biological moieties and has the future to be used as an alternative source of energy. The aim of this review is to summarize the background and state-of-the-art in the field of eBFCs. This review article will be very beneficial for a wide audience including students and new researchers in the field. A part of the paper summarized the challenges in the preparation of anode and cathode and the involvement of nanomaterials and conducting polymers to construct the effective bioelectrodes. It will provide an insight for the researchers working in this challenging field. Furthermore, various applications of eBFCs in implantable power devices, tiny electronic gadgets, and self powered biosensors are reported. This review article explains the development in the area of eBFCs for several years from its origin to growth systematically. It reveals the strategies that have been taken for the improvements required for the better electrochemical performance and operational stability of eBFCs. It also mentions the challenges in this field that will require proper attention so that the eBFCs can be utilized commercially in the future. The review article is written and structurized in a way so that it can provide a decent background of eBFCs to its reader. It will definitely help in enhancing the interest of reader in eBFCs.

Antimicrobial activity of fusidic acid inclusion complexes.

OBJECTIVES: To synthesize and characterize the inclusion complexes of fusidic acid with ß - cyclodextrin, followed by the evaluation of their antimicrobial activity against pure strain (Staphylococcus aureus ATCC 25,923) and isolated Staphylococcus from clinical cases. METHODS: The desired compounds were synthesized using molar ratio of fusidic acid: ß-cyclodextrin of 1:1. Synthesized compounds were analyzed by Fourier Transform Infrared Spectroscopy (FTIR), X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and Thermal Analysis, and the results confirmed the formation of inclusion compounds by fusidic acid with ß-cyclodextrin. RESULTS: Physical-chemical characterization confirmed the preparation of desired inclusion compounds, and the antimicrobial test confirmed that all compounds obtained have antimicrobial activity. Antimicrobial activity of freeze-drying complex againstS. aureus is similar with pure fusidic acid activity, being better than the cefoxitin one. Similar behavior was observed against methicillin-resistant S. aureus and S. epidermidis. CONCLUSIONS: In the present work, three different inclusion complexes of fusidic acid were prepared using three different preparation methods. All inclusion complexes obtained presented good antimicrobial activity against differentS. aureus strains. Antimicrobial activity of these new prepared compounds was observed to be better than that of cefoxitin.