Effect of Formulation Variables on the Preparation and in Vitro-in Vivo evaluation of Cimetidine Release from Ethyl Cellulose Micropellets

Ethyl cellulose embedded prolonged release microparticles containing cimetidine was designed by dispersing the drug-ethyl cellulose mixture in acetone, into a medium of mineral oil and subsequent rigidization of the ethyl cellulose matrix. Significant reproducibility of the manufacturing process was observed. In vitro-in vivo correlation revealed the the dissolution process is the rate determining step in drug absorption and the significant in vivo efficiency of the dosage form is well expected.     

A Comprehensive Survey of Emergency Communication Network and Management

Wireless Personal Communications - The performance of wireless communication network is important in emergency rescue operations while ensuring optimum usage of limited wireless resources. Due to...     

Effects of Solvents, Temperature, and Plasticizer on Film Coating of Tablets

The effects of solvent composition, temperature, solvent retention, plasticizers, and polishing on the disintegration and percent dissolution of various nonaqueous film coated tablets were studied. A mixture of isopropanol-dichloromethane used as solvent systems for the film coating of ranitidine hydrochloride tablets resulted in reduced film peel-off time, decreased disintegration time, and increased percent dissolution. The effect of prewarming the coating bed of cimetidine tablets revealed an increase in percent dissolution compared to no prewarming condition. In contrast, an increase in temperature of the tablet bed resulted in higher disintegration time and lower percent dissolution of ibuprofen tablets. Ranitidine hydrochloride film coated tablets polished with polyethylene glycol showed lower disintegration time and higher percent dissolution than those polished with beeswax. The presence of plasticizer in the coating solution resulted in decreased disintegration time and higher percent dissolution for norfloxacin tablets.     

Photomechanical degradation of thermoplastic elastomers

The photodegradation of thermoplastic elastomers designed for outdoor applications was studied with laboratory ultraviolet (UV) exposure in the unstrained state and under tensile strain (25 and 50%). Strained exposure caused a reduction of the strain to failure in subsequent tensile tests. For some combinations of material and exposure conditions, some recovery of extensibility occurred between 2 and 4 weeks. Microscopic examination revealed that this was probably due to embrittlement of the surface region that was sufficiently severe that surface cracks did not propagate into the interior and that the observed recovery did not correspond to repair or improvement of the material. Shielding the sample surface from UV irradiation reduced the formation of surface cracking very significantly, and it was deduced that the principal cause of degradation was photooxidation rather than ozone attack. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 150–161, 2006     

Analytical method to detect adulteration of ground roasted coffee

In this work, an HPLC-based detection method for identification of coffee powder adulterated with roasted barley, wheat and rice powders was developed by using various chemical indices such as monosaccharides (mannose, rhamnose, glucose, galactose, xylose and arabinose), trigonelline and nicotinic acid. As a quality assurance, the recovery efficiencies were 84.1%–90.2% for the monosaccharides, 113.6% for trigonelline and 114.9% for nicotinic acid. The limits of detection were 0.047–0.070 mmol kg⁻¹ for the monosaccharides, 0.209 mg kg⁻¹ for trigonelline and 0.117 mg kg⁻¹ for nicotinic acid. The glucose concentration in coffee samples adulterated with roasted barley, wheat and rice at 99:1 (w/w) mixing ratio was significantly different from the control coffee sample. The limit of discrimination from adulterated coffee samples was 1% (w/w) when glucose was used as a chemical index (P < 0.05).     

Highly dispersed platinum nanoparticles on graphitic carbon nitride: A highly active and durable electrocatalyst for oxidation of methanol,formic acid and formaldehyde

Finding efficient electrocatalyst for oxidation of small organic molecules such as methanol (CH₃OH), formic acid (HCOOH), formaldehyde (HCHO) etc. is essential for the development of their respective direct fuel cells. We report here highly dispersed platinum nanoparticles (PtNPs) on carbon nitride (CN_x) were successfully synthesized by the ultrasound mediated sodium borohydride reduction of H₂PtCl₆ in presence of CN_x nanosheets. This platinum–carbon nitride (Pt/CN_x) composite exhibited superior electrocatalytic activity towards oxidation of CH₃OH, HCOOH and HCHO in acid media. The mass activity, onset potential, tolerance to carbon monoxide (CO) poisoning and long term durability for the catalytic oxidation of CH₃OH, HCOOH, HCHO on Pt/CN_x catalyst in acid media is much higher than that of commercial Pt/C catalyst. The mass activity of Pt/CN_x catalyst at ～0.64 V (forward scan) is 310 mA/mg_Pt which is 2.7 time higher than that of commercial Pt/C for methanol oxidation. The electrooxidation of HCOOH on Pt/CN_x occurs via dual mechanism with greatly enhanced oxidation through dehydrogenation pathway in comparison with commercial Pt/C. The mass activity on Pt/CN_x at 0.3 V (vs. NHE) is 25 times higher than that of Pt/C for oxidation of HCOOH. The superior catalytic activity and durability of this Pt/CN_x catalyst can be attributed to high dispersion of PtNPs and strong catalyst support interaction.     

Physical and antimicrobial properties of banana flour/chitosan biodegradable and self sealing films used for preserving Fresh-cut vegetables

Kluai Namwa is a local species of banana grown in Thailand. Flour made from this banana was mixed with chitosan, a by product of the shrimp industry, for casting films as it has valuable characteristics including antimicrobial effects. Utilization of excess banana available in high season and chitosan can from the waste crustacean shells could help reduce waste while making available a value added product. Banana/chitosan films were produced using 0.5–2 g banana flour and 0.5 g chitosan in 100 ml aqueous solution. Film water vapor permeability, tensile properties, solubility and morphology were investigated. The composite yellowish film exhibited great water permeability of 38.81–41.66 g mm/m² day kPa. Tensile strength and elongation were in the range of 5.19–14.22 MPa and 1.64–2.59%, respectively while the solubility obtained was 40.90–64.21%. The presence of starch in the composite film makes possible water soluble and sealable bags or wraps, while the presence of chitosan gives them the antimicrobial property. The composite bags were found to protect asparagus, baby corn and Chinese cabbage against Staphylococcus aureus activity by serving as a good barrier and as a antimicrobial agent. With these properties the edible bag with its contents can be processed together during food preparation making its use very convenient.     

Mixed convective heat transfer enhancement in a ventilated cavity by flow modulation via rotating plate

The present study numerically explores the mixed convection phenomena in a differentially heated ventilated square cavity with active flow modulation via a rotating plate. Forced convection flow in the cavity is attained by maintaining external fluid flow through an opening at the bottom of the left cavity wall while leaving it through another opening at the right cavity wall. A counter-clockwise rotating plate at the center of the cavity acts as an active flow modulator. Moving mesh approach is used for the rotation of the plate and the numerical solution is achieved using arbitrary Lagrangian-Eulerian finite element formulation with a quadrilateral discretization scheme. Transient parametric simulations have been performed for various frequency of the rotating plate for a fixed Reynolds number (Re) of 100 based on maximum inlet flow velocity while the Richardson number (Ri) is maintained at unity. Heat transfer performance has been evaluated in terms of spatially averaged Nusselt number and time-averaged Nusselt number along the heated wall. Power spectrum analysis in the frequency domain obtained from the fast Fourier transform analysis indicates that thermal frequency and plate frequency start to deviate from each other at higher values of velocity ratio (>4).