Controlled precipitation for enhanced dissolution rate of flurbiprofen: development of rapidly disintegrating tablets

Objective: The aim of this work was to investigate the potential of controlled precipitation of flurbiprofen on solid surface, in the presence or absence of hydrophilic polymers, as a tool for enhanced dissolution rate of the drug. The work was extended to develop rapidly disintegrated tablets.

Significance: This strategy provides simple technique for dissolution enhancement of slowly dissolving drugs with high scaling up potential.

Methods: Aerosil was dispersed in ethanolic solution of flurbiprofen in the presence and absence of hydrophilic polymers. Acidified water was added as antisolvent to produce controlled precipitation. The resultant particles were centrifuged and dried at ambient temperature before monitoring the dissolution pattern. The particles were also subjected to FTIR spectroscopic, X-ray diffraction and thermal analyses.

Results: The FTIR spectroscopy excluded any interaction between flurbiprofen and excipients. The thermal analysis reflected possible change in the crystalline structure and or crystal size of the drug after controlled precipitation in the presence of hydrophilic polymers. This was further confirmed by X-ray diffraction. The modulation in the crystalline structure and size was associated with a significant enhancement in the dissolution rate of flurbiprofen. Optimum formulations were successfully formulated as rapidly disintegrating tablet with subsequent fast dissolution.

Conclusions: Precipitation on a large solid surface area is a promising strategy for enhanced dissolution rate with the presence of hydrophilic polymers during precipitation process improving the efficiency.     

Determination of antioxidant activity of surface‐treated PET films coated with rosemary and clove extracts

Commercial PET films were surface treated and subsequently coated with either rosemary (RME) or clove (CE) extracts. Surface treatments involved (1) corona treatment, (2) chemical modification, and (3) plasma treatment. Radical scavenging activity (RSA) of both pure plant extracts and coated film extracts were determined using the 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH) method. RME‐coated films showed a % RSA of 25.6%, 22.4%, and 24.1% for plasma, chemical modification, and corona treatment, respectively, at an extract concentration of 1402 ppm, respectively, while pure RME showed a %RSA of 16.0%. Respective %RSA values for CE were 25.0% for plasma, 25.2% for chemically modified, and 25.2% for corona‐treated films at 1402 ppm, while pure CE showed a %RSA of 47.6%. Thiobarbituric acid (TBA) test, performed on ground fish muscle wrapped in all types of employed films, showed a remarkable decrease in the degree of fish oxidation ranging between 50.0 and 80.0% after 6 days of storage. Contact angle measurements confirmed that surface chemically modified films had the highest adhesion strength followed by corona and plasma‐treated films. Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and X‐ray photoelectron spectroscopy (XPS) data also supported contact angle measurements. Finally, the oxygen permeability of surface‐treated films did not differ from untreated films indicating that surface treatment did not affect film barrier properties.     

Rheology and thermal conductivity of calcium grease containing multi-walled carbon nanotube

Recently, nanofluids attract considerable interest for enhanced rheological behavior and thermal performance. The aim of this research is to study the influence of additives Multi-Walled Carbon Nanotubes (MWCNTs) on the rheological behavior and its structure, thermal conductivity, and the influence of shear thinning rate on oil separation at different temperatures for calcium grease. Various concentrations of MWCNTs (0.5, 1, 2, 3, and 4%) have been added to the grease to obtain the best percentages that improve the properties of nanofluid. The microstructure of MWCNTs and nanofluid were examined by X-ray diffraction (XRD), Transmission Electron Microscope (TEM), and Scanning Electron Microscope (SEM). These experimental investigations were evaluated with a Brookfield programmable Rheometer DV-III ULTRA. The results indicated that the optimum concentration of MWCNTs was 3%, and the dropping point increasing about 11%. The rheological behaviors of the nanofluids show that the grease with various concentrations of MWCNTs demonstrates non Newtonian behaviors and the results indicated that the shear stress, apparent viscosity and thermal conductivity increase with the increase of volume concentration of MWCNTs to 65%, 52%, and% 56, respectively.     

Investigating optical,electrical, and mechanical traits of thiourea admixtured KDP single crystals to explore NLO device applications

The 0.5 and 1 mol% thiourea “mixed” potassium dihydrogen phosphate (KDP) crystals have been developed by conventional slow solution evaporation method. The crystallographic parameters of grown crystals have been determined by employing single crystal X-ray diffraction technique. The functional groups of grown crystals were successfully identified by means of FTIR spectral analysis. The optical transmittance is 79%, 84%, and 89% for KDP, 0.5 mol thiourea mixed KDP, and 1 mol thiourea mixed KDP crystal. The energy band gap (E_g) of KDP, 0.5 mol thiourea mixed KDP, and 1 mol thiourea mixed KDP crystal is 3.71 eV, 3.61 eV, and 3.75 eV, respectively. The Kurtz–Perry test has been employed to determine the SHG efficiency and SHG efficiency of 0.5 and 1 mol thiourea mixed KDP crystal is 2.09 and 2.22 times superior to KDP crystal. Effect of thiourea mixing on hardness properties of KDP crystal have been scrutinized using the Vickers microhardness studies. The frequency dependent dielectric behavior of grown crystals has been analyzed at room temperature.

     

Atomically Precise Prediction of 2D Self‐Assembly of Weakly Bonded Nanostructures: STM Insight into Concentration‐Dependent Architectures

A joint experimental and computational study is reported on the concentration‐dependant self‐assembly of a flat C₃‐symmetric molecule on a graphite surface. As a model system a tripodal molecule, 1,3,5‐tris(pyridin‐3‐ylethynyl)benzene, has been chosen, which can adopt either C_3h or C_s symmetry when planar, as a result of pyridyl rotation along the alkynyl spacers. Density functional theory (DFT) simulations of 2D nanopatterns with different surface coverage reveal that the molecule can generate different types of self‐assembled motifs. The stability of fourteen 2D patterns and the influence of concentration are analyzed. It is found that ordered, densely packed monolayers and 2D porous networks are obtained at high and low concentrations, respectively. A concentration‐dependent scanning tunneling microscopy (STM) investigation of this molecular self‐assembly system at a solution/graphite interface reveals four supramolecular motifs, which are in perfect agreement with those predicted by simulations. Therefore, this DFT method represents a key step forward toward the atomically precise prediction of molecular self‐assembly on surfaces and at interfaces.     

Heat and mass transfer characteristics in a spray chamber

This paper presents a one-dimensional mathematical model for heat and mass transfer of water droplets in a spray chamber. The model includes drop size distribution and velocity of the droplets generated by a nozzle of inlet diameter 3.2 mm. By using the conservation of mass and energy, the changes in water temperature, air temperature and humidity along the spray cone in the spray chamber can be calculated. This model is tested with two different water mass flows. The results look reasonable from practical point of view and they also show that higher water mass flow results in a higher air temperature drop and higher humidity.     

Exploration of Advanced Electrode Materials for Approaching High‐Performance Nickel‐Based Superbatteries

The surging interest in high performance, low‐cost, and safe energy storage devices has spurred tremendous research efforts in the development of advanced electrode active materials. Herein, the in situ growth of zinc–iron layered double hydroxide (Zn–Fe LDH) on graphene aerogel (GA) substrates through a facile, one‐pot hydrothermal method is reported. The strong interaction and efficient electronic coupling between LDH and graphene substantially improve interfacial charge transport properties of the resulting nanocomposite and provide more available redox active sites for faradaic reactions. An LDH–GA||Ni(OH)₂ device is also fabricated that results in greatly enhanced specific capacity (187 mAh g^?1 at 0.1 A g^?1), outstanding specific energy (147 Wh kg^?1), excellent specific power (16.7 kW kg^?1), along with 88% capacity retention after >10 000 cycles. This approach is further extended to Ni–MH and Ni–Cd batteries to demonstrate the feasibility of compositing with graphene for boosting the energy storage performance of other well‐known Ni‐based batteries. In contrast to conventional Ni‐based batteries, the nearly flat voltage plateau followed by a sloping potential profile of the integrated supercapacitor–battery enables it to be discharged down to 0 V without being damaged. These findings provide new prospects for the design of high‐performance and affordable superbatteries based on earth‐abundant elements.