No abstract

The purpose of this work was to develop a multiparticulate system exploiting the pH-sensitive property and biodegradability of calcium alginate beads for intestinal delivery of ceftriaxone sodium (CS). CS was entrapped in beads made of sodium alginate and sodium carboxymethylcellulose (CMC), acacia, HPMC K4M and HPMC K15M as drug release modifiers. Beads were prepared using calcium chloride as a cross-linking agent, followed by enteric coating with cellulose acetate phthalate (CAP). The beads were then evaluated for entrapment efficiency using HPLC, in vitro drug release examined in simulated gastric fluid (pH 1.2) and simulated intestinal fluid (pH 6.8), swellability, particle size and surface characterization using optical microscopy, scanning electron microscopy (SEM), and atomic force microscopy (AFM). Thermal gravimetric analysis (TGA) was utilized to check the polymer matrix strength and thermal stability. The drug entrapment efficiency of the optimized formulation was determined to be 75 ± 5 %. Swelling properties of drug-loaded beads were found to be in a range of 0.9–3.4. Alginate beads coated with CAP and containing CMC as a second polymer exhibited sustained release. The drug release followed first-order kinetics via non-Fickian diffusion and erosion mechanism. The particle size of the beads was between 1.04 ± 0.20 and 2.15 ± 0.36 mm. TGA, AFM, and SEM data showed composition and polymer-dependent variations in cross-linking, thermal stability, surface structure, morphology, and roughness. The physico-chemical properties of the developed formulation indicate suitability of the formulation to deliver CS orally.

The aim of this research was to advance solid lipid nanoparticle (SLN) preparation methodology by preparing glyceryl monostearate (GMS) nanoparticles using a temperature-modulated solidification process. The technique was reproducible and prepared nanoparticles without the need of organic solvents. An anticancer agent, 5-fluorouracil (5-FU), was incorporated in the SLNs. The SLNs were characterized by particle size analysis, zeta potential analysis, differential scanning calorimetry (DSC), infrared spectroscopy, atomic force microscopy (AFM), transmission electron microscopy (TEM), drug encapsulation efficiency, in vitro drug release, and in vitro cell viability studies. Particle size of the SLN dispersion was below 100 nm, and that of redispersed lyophilizates was ~500 nm. DSC and infrared spectroscopy suggested that the degree of crystallinity did not decrease appreciably when compared to GMS. TEM and AFM images showed well-defined spherical to oval particles. The drug encapsulation efficiency was found to be approximately 46%. In vitro drug release studies showed that 80% of the encapsulated drug was released within 1 h. In vitro cell cultures were biocompatible with blank SLNs but demonstrated concentration-dependent changes in cell viability to 5-FU-loaded SLNs. The 5-FU-loaded SLNs can potentially be utilized in an anticancer drug delivery system.

To improve radiative transfer calculations for inhomogeneous clouds, a consistent means of modeling inhomogeneity is needed. One current method of modeling cloud inhomogeneity is through the use of fractal paramdemonstrate both the strengths and weaknesses of these models•

Introduced in the Genesis Flood by Whitcomb and Morris (1961) and fleshed out by Oard (1979) a model for an ice age in the wake of the Genesis flood was used to explain the evidence of glaciation in Canada and the United States without resorting to eons of time. It was proposed that this rapid ice age was the consequence of post flood warm oceans, barren land and volcanic aerosols. The impact of warm oceans was simulated by Vardiman (1998) and Gollmer (2013) using climate models. Although warm oceans increase precipitation in the Arctic, global surface temperatures become unbearably hot unless volcanic aerosols equivalent to the eruption of Toba are used. In addition, with ocean temperatures of 30 ˚C the formation of snow and ice are impossible because air and land temperatures in the Arctic remain above freezing. Using dynamic oceans with a uniform initial temperature of 24 ˚C, climate simulations are performed to explore the impact of aerosol distributions on the position of the jet stream and storm tracks. In previous simulations, precipitation in the Arctic is primarily over the ocean rather than land, thus limiting how quickly ice sheets are able to grow. Although the simulations reported here are still too warm for the accumulation of snow, it is clear that the thermal circulation coming off a cold continent must be offset by other factors in order for sufficient precipitation to fall inland.