Number concentration dependence of ultrasonic disruption ratio of diameter-sorted microcapsules

The use of ultrasound to destroy microcapsules in microbubble-assisted drug delivery systems (DDS) is of great interest. In the present study, the disruption ratios of capsule clusters were measured by observing and experimentally analyzing microcapsules with polymer shells undergoing disruption by ultrasound. The microcapsules were dispersed in a planar microchamber filled with a gelatin gel and sonicated using 1 MHz focused ultrasound. Different capsule populations were obtained using a filtration technique to modify and control the capsule sizes. The disruption ratio as a function of the concentration of capsules was obtained through image processing of the recorded photomicrographs. We found that the disruption ratio for each population exponentially decreases as the particle number concentration (PNC) increases. The maximum disruption ratio of the diameter-sorted capsules was larger than that of polydispersed capsules. Particularly, for resonant capsule populations, the ratio was more than twice that of polydispersed capsules. Furthermore, the maximum disruption ratio occurred at higher concentrations as the mean particle diameter of the capsule cluster decreased.

Research on Energy Dissipation Laws of Coal Crushing under the Impact Loads

Dynamic crushing characteristics of coals are closely related with energy absorption and release of coals under certain strain rate. Hence, it is necessary to investigate energy dissipation laws of coal crushing under the impact loads with different strain rates. Based on the dynamic and static mechanical tests, crushing energy, total absorption energy, total releasable elastic latent energy, and relations between fractal feature of fragments, mean particle diameter and energy during crushing behaviors of outburst coal and nonoutburst coal were investigated. According to research results, crushing energy, total absorption energy, and releasable elastic latent energy of outburst coal and nonoutburst coal are related with strain rate, and they present exponential growths with the increase of the strain rate. However, the energy dissipation rate (ratio of crushing energy and incident energy) was basically constant at about 10%∼20%, that is, energy dissipation rate is a variable unrelated with strain rate. There is a good logarithmic relationship between the dynamic compressive strength of coals and the absorption energy density and elastic latent energy density, and dynamic comprehensive strength of coals has important impacts on energy absorption. The fractal features of coal fragments were obvious under dynamic impacts. The higher fractal dimension of fragment and the smaller mean particle diameter of experimental fragments bring the greater energy needed.

Analytical Solutions for Characterizing Fluid Flow through Sand-Pack in Pipes

When fluid flows through a pipe that is packed with sand particles, the fluid will bear the resistance from the sand-pack, as well as the viscous shear from the pipe wall. If the viscous shear from the pipe wall can be neglected, the fluid flow will obey Darcy’s law, and one can think the equivalent permeability of the packed-pipe equals the permeability of the sand-pack. However, if the viscous shear from the pipe wall cannot be neglected, the fluid flow will obey the Brinkman equation, and the permeability of the packed-pipe will be less than that of the sand-pack due to the additional viscous drag. In this work, on the basis of the Brinkman equation, we derived a series of analytical solutions for characterizing the fluid flow in packed-pipes. These solutions can be used to depict the velocity profiles, estimate the flux rate, and calculate the equivalent permeability of a packed-pipe. On the basis of these analytical solutions, we found that Poiseuille’s law is a special form of the derived equivalent permeability solution. We further divided the fluid flow in a packed-pipe into three regimes, including N-S flow, Brinkman flow, and Darcy flow. During the regime of Brinkman flow, the dimensionless flow velocity at the pipe center is 1, and the dimensionless flow velocity is gradually decreased to 0 at the pipe wall. We also investigated the effects of sorting, sand particle size, and sand-pack porosity on the packed-pipe permeability. The calculated results show that a more uniform size of the sand particles or a smaller mean particle diameter can lead to lower packed-pipe permeability. Compared to the sorting and mean particle diameter, the sand-pack porosity exerts a more significant effect on the packed-pipe permeability.

Influence of combined hydrolyzed collagen and maltodextrin as carrier agents in spray drying of cocona pulp

This work aimed to evaluate the effect of carrier agents containing maltodextrin and protein, represented by hydrolyzed collagen on the spray drying process of cocona (Solanum sessiliflorum Dunal), and on the properties of the resulting powders. We used pre-established proportions between the solids of cocona pulp and the carrier agents (P:CA), and among carrier agents themselves, maltodextrin and hydrolyzed collagen, (MD:HC). The process was carried out in a spray dryer at an inlet air temperature of 120 ºC. We prepared twelve feed solutions containing 20% of total solids, with P:CA ratios of 1:3, 1:4, 1:5 and 1:6, and MD:HC ratios of 0:100, 50:50, and 100:0. Solids recovery was obtained for the evaluation of the spray drying process. The cocona pulp powders were analyzed for moisture content, water activity, particle size distribution, mean particle diameter, chemical structure (FTIR) and color. For a P:CA of 1:6, for the sample formulated with hydrolyzed collagen only, solids recovery (96.2%) was much higher than that of the sample with maltodextrin only (39.2%). The chemical structure of cocona powders can be considered a sign of a good encapsulation process. The color of the cocona pulp powder was similar to that of the carrier agents. The formulation with highest content of hydrolyzed collagen improved the recovery of solids, guaranteed the cocona pulp encapsulation, and obtained fruit powders with bioactive properties.

Effect of PVP on the Morphology and Growth of Cu Hierarchical Nanostructures Prepared by Electroless Deposition

Octahedral Cu hierarchical nanostructures were prepared by electroless deposition in aqueous solution at 80 °C. Polyvinyl pyrrolidone (PVP) was employed as the protective and structure directing agent to prevent oxidation and agglomeration of the Cu products. Addition of higher amounts of PVP (about 1.275 g) resulted in smaller but irregularly-shaped Cu nanoparticles. The Cu nanoparticles have a mean particle diameter of about 200 nm with excellent size distribution. On the other hand, Cu octahedrals were produced when 0.425 to 0.850 g PVP was used. In situ mixed potential monitoring of the solution during electroless deposition revealed that the mixed potential was more positive at larger amounts of PVP. This can be attributed to slower reduction rate due to the decrease in the activity of Cu(II) ions. Consequently, smaller Cu nanoparticles were produced.

Influence of nucleating agent type on the morphology of extruded polyetherimide foam for printed circuit boards*

This work focuses on the development of foamed high temperature thermoplastic substrates for printed circuit boards. For this application it is necessary to achieve mean cell diameters smaller than 30 µm in order to be able to realize vias and high packaging densities (miniaturization). Different additives as nucleating agents, namely macro- and micro-crystalline talc, silica, calcium carbonate, and wollastonite, were melt-compounded with polyetherimide using a twin-screw extruder. Foamed samples are prepared by foam extrusion using a slit die and CO2 as physical blowing agent. The aim of this study is to analyze the influence of the mean particle size and the particle surface tension on the mean cell diameters. Therefore, the shape of the additives, the foam morphology, and the elongational viscosity were considered. The additives with a suitable particle size and surface tension exhibit a positive influence on the foam morphology, resulting in smaller cell diameters (<30 µm), a narrower cell size distribution and a foam density lower than 900 kg/m3. If the mean particle diameter of the nucleating agents is lower than 0.6 µm in this study, no nucleation effect could be observed. This is related to the fact that no heterogeneous nucleation occurs, if the particle diameter is too small. If the mean particle diameter of the used additives is larger than 1.5 µm, which could be demonstrated in this study in case of polyetherimide, then the additive acts as nucleating agent and heterogeneous nucleation occurs. Furthermore, it was observed that the mean cell diameter was affected by the different surface tensions of the studied nucleating agents.

Preparation and Evaluation of Chitosan Loaded Naproxen Nanoparticles by Emulsion Interfacial Reaction Method

Aim: The aim of this investigation was to develop and characterize naproxen loaded chitosan nanoparticles by emulsion interfacial reaction method. Methodology: For emulsion interfacial reaction method chitosan was used as a polymer. In this method, eight formulations were prepared by varying drug to polymer concentration. Discussion: Out of eight formulations prepared using emulsion interfacial reaction method EI8 formulation was found to be the best formulation. The drug content was observed as 94.4%, entrapment efficiency and loading capacity were found to be 87.5% and 75%, respectively. The mean particle diameter was measured as 324.6nm and the Zeta potential value was found to be -42.4mv. In vitro drug release data showed 97.2% of drug release rate sustained up to 12hrs. Conclusion: The results clearly reveal that EI8 formulation having the highest amount of drug was considered as the best formulation because of its small mean particle diameter, good entrapment efficiency, and stability.

Improving Relative Bioavailability of Oral Imidazolidinedione by Reducing Particle Size Using Homogenization and Ultra-Sonication

Particle size is an important determinant of gastrointestinal absorption of compounds administrated orally. The present study evaluates the effect of a reduction in particle size assessed by homogenization, sonication, and homogenization plus sonication on the bioavailability of imidazolidinedione (IZ), an antimalarial compound with known causal prophylactic activity and radical cure of relapsing malaria. Formulations were administrated intragastrically to mice, and blood samples were collected for LC-MS/MS analysis. The homogenization method manually decreased particle size with minimal variance, resulting in a mean particle diameter of 42.22 μm, whereas the probe sonication method evenly distributed pulses of sound to break apart particles, resulting in a mean diameter of 1.50 μm. Homogenization plus sonication resulted in a mean particle diameter of 1.44 μm, which was similar to that of the sonication method alone. The compound suspensions did not show a significant difference in mean particle size between the different vehicles. The sonically engineered microparticle delivers high sonic energy to the suspension leads to faster breakdown and stabilizing of the micronized particles when compared with homogenizer. The bioavailability of the small particle IZ formulation was 100%, compared to the 55.79% relative bioavailability of IZ with larger particle size. These initial data clearly show that a reduction in particle size of orally administered IZ with probe sonication could significantly increase bioavailability in rodent animals that is affected by a high first-pass effect.

Microencapsulation of a Model Oil in Wall System Consisting of Wheat Proteins Isolate (WHPI) and Lactose

Microencapsulation allows for the entrapment, protection, and delivery of sensitive and/or active desired nutrients and ingredients as well as biologically-active agents. The microencapsulating properties of wall solutions (WS) containing 2.5–10% (w/w) wheat proteins isolate (WHPI) and 17.5–10% (w/w) lactose were investigated. Core-in-wall-emulsions (CIWEs) consisting of the WS and soy oil were prepared at a wall-to-core (W:C) ratio ranging from 25:75 to 75:25 (w/w). Microcapsules were prepared by spray-drying the CIWEs. The CIWEs had a mean particle diameter smaller than 0.5 µm and surface excess that ranged from 1.59 to 5.32 mg/m2. In all cases, microcapsules with smooth outer surfaces that exhibited only limited surface indentation were obtained. The core, in the form of protein-coated lipid droplets, was embedded throughout the wall matrices. In all but one case, core retention was higher than 83%, and in 50% of the cases, it was higher than 90%. Core retention was significantly influenced the composition of the WS and by W:C ratio (p < 0.05). Except for two cases, microcapsules exhibited very limited core extractability. The microencapsulation efficiency was >90% and was influenced, to a certain degree, by the composition of the CIWEs. Results indicated the potential for utilizing wall systems consisting of WHPI and lactose as effective and highly functional microencapsulating agents in food and related applications.

Karakterisasi dan Uji Stabilitas Digestif Nanoemulsi β-Karoten yang Dibuat dengan Metode Emulsifikasi Spontan

β-Carotene exhibits a wide range of health benefits, but its application in food formulation is very limited because of its instability and susceptibility to degradation. The stability of β-carotene can be improved by incorporation into an oil-in-water (o/w) emulsions. The objective of this research was to characterize β-carotene loaded nanoemulsions prepared with spontaneous emulsification method using ternary food-grade surfactants (Tween 80, Span 40, Span 80) and palm oil or VCO (virgin coconut oil) as oil phase with the surfactant-oil ratio of 4. The physicochemical stability of β-carotene loaded nanoemulsions during simulated digestions, which consist of the mouth, stomach, and intestine phases, was also evaluated using in-vitro digestion model. The results showed that β-carotene loaded nanoemulsions, prepared either using VCO or palm oil as the oil phase, had neutral pH (6.8±0.1), mean particle diameter of 129 -159 nm, showed monomodal particle size distribution with low polydispersity index (PdI) values (0.214 - 0.266), and were not significantly different in zeta potential values ([-6,59]–[-8,9]). The β-carotene loaded nanoemulsions with VCO as the oil phase had a smaller mean particle diameter than that of palm oil. The physical stability of the β-carotene loaded nanoemulsions against digestive simulation in the mouth, stomach or intestine phases was not influenced by the oil phase type. Both nanoemulsions were stable against simulated digestion in the mouth and stomach phases. After passing through the intestinal phase, the mean particle diameter increased and the particle size distribution changed from monomodal to bimodal. The β-carotene retention after passing through the mouth, stomach and intestinal phases of the β-carotene loaded nanoemulsion prepared using VCO were not significantly different from the palm oil. ABSTRAKβ-Karoten mempunyai berbagai manfaat kesehatan, namun aplikasinya dalam formulasi pangan sangat terbatas karena tidak stabil dan mudah mengalami degradasi. Stabilitas β-karoten dapat ditingkatkan dengan menggabungkannya dalam sistem penghantaran berbasis emulsi minyak dalam air (o/w). Penelitian ini bertujuan untuk melakukan karakterisasi nanoemulsi β-karoten yang dibuat dengan metode emulsifikasi spontan menggunakan kombinasi tiga surfaktan food grade (Tween 80, Span 40, Span 80), minyak sawit maupun VCO (virgin coconut oil) sebagai fase minyak dengan rasio surfaktan-fase minyak 4.. Penelitian ini juga mengkaji stabilitas fisikokimiawi nanoemulsi β-karoten selama pencernaan di mulut, lambung dan usus dengan menggunakan model digesti in vitro. Hasil penelitian memperlihatkan bahwa nanoemulsi β-karoten yang dibuat dengan fase minyak VCO maupun minyak sawit memiliki pH netral (6,8±0,1), rerata diameter partikel 129–159 nm, distribusi ukuran partikel monomodal dengan nilai indeks polidispersitas (polydispersity index, PdI) rendah (0,214–0,266) dan zeta potensial yang tidak berbeda nyata ([-6,59]–[-8,9]). Nanoemulsi β-karoten dengan fase minyak VCO memiliki rerata diameter partikel yang lebih kecil dibanding minyak sawit sebagai fase minyak. Jenis fase minyak tidak berpengaruh terhadap stabilitas fisik nanoemulsi β-karoten selama simulasi pencernaan di mulut, lambung maupun usus. Nanoemulsi β-karoten dengan fase minyak VCO maupun minyak sawit stabil terhadap pencernaan di mulut maupun lambung. Setelah melewati fase usus, terjadi peningkatan diameter partikel rerata dan perubahan distribusi ukuran partikel dari monomodal menjadi bimodal. Retensi β-karoten dalam nanoemulsi VCO setelah melewati simulasi pencernaan mulut, lambung dilanjutkan fase usus tidak berbeda nyata dengan retensi β-karoten dalam nanoemulsi minyak sawit.