We have had a successful exhibition at the Ceramics Expo 2017 in Cleveland, OH. Many good and interesting discussions on how to apply Freeze Granulation on diffrent Ceramic powder systems.
Today is the last day of three, if you are here come and say hello at our stand No 126.
Jae-Young Her, Kwang-Geun Lee
The analgesic and physical properties of acetaminophen powder suitable as an inhaled drug produced by spray freeze-drying (SFD) were compared with those of raw acetaminophen. A laser particle size analyzer and scanning electron microscopy (SEM) were applied to estimate physical structure and properties of the particles. A cyclooxygenase (COX) inhibitor screening assay was used to compare the antipyretic and analgesic activity of raw and SFD acetaminophen. According to SEM, SFD acetaminophen particles had various shapes and sizes with porous structures. The optimized conditions for solvent, annealing temperature, and annealing time were water/ethanol mixture (60% water and 40% ethanol), −40°C, and 7 h, respectively. The diameter of optimized acetaminophen powder was 7.33 µm, and the aerodynamic particle size was 3.38 µm. The antipyretic and analgesic activities of acetaminophen after SFD were from 84.3 to 97.1% for COX-1 and from 91.6 to 102.9% for COX-2 compared to those of raw acetaminophen, respectively.
Acetaminophen, inhaled drug, optimized solvent, powder process, spray freeze-drying
Spray freeze granulation of submicrometre α-alumina using ultrasonicati
S. Ghanizadeh, P. Ramanujam, B. Vaidhyanathan, J. Binner
Granulation is a key factor towards improvement of the flowability of fine ceramic powders to make them suitable for industrial dry pressing. Controlled granulation of fine alumina particles with a primary particle size of ∼ 150 nm was carried out using spray-freeze drying, which led to the production of flowable granules with high crushability. The fracture surface of uniaxially die-pressed green bodies made from granules with density values of ≥ 50 % of theoretical showed a uniform microstructure. Sintering experiments were performed using conventional single- and two-stage radiant heating methods followed by density and grain size measurement and characterisation of the final dense compacts to study the efficiency of two-stage sintering in grain growth elimination. The results have been compared with those of alumina bodies prepared using similar suspension by the slip-casting route.
Alumina, granulation, spray-freeze drying, two-stage sintering
Effect of freeze-drying treatment on the optical properties of SPS-sintered alumina
M. Suárez, A. Fernández, J.L. Menéndez, M. Nygren, R. Torrecillas, Z. Zhao
This study looks at the influence of alumina powder processing on the preparation of transparent alumina by Spark Plasma Sintering (SPS). Zeta potential measurements were carried out on alumina suspensions in order to determine the best dispersion conditions. Stable slurries were submitted to a spray freeze drying process and their sintering behavior was compared with the corresponding non spray freeze dried powders. Transparent alumina samples were successfully prepared from alumina powders by Spark Plasma Sintering. An optical model considering pore and grain size distributions has been developed to obtain information about porosity in dense materials. It was found that the final density and, accordingly, the optical properties were improved when spray freeze dried starting powder was used.
A. Sintering; C. Optical properties; D. Al2O3
W.F. Tonnis, J.-P. Amorij, M.A. Vreeman, H.W. Frijlink, G.F. Kersten, W.L.J. Hinrichs
The current hepatitis B vaccines need to be stored and transported under refrigerated conditions (2–8 °C). This dependence on a cold-chain is highly challenging in areas where hepatitis B virus infections are endemic. To decrease the cold-chain dependency, powder formulations of the hepatitis B surface antigen (HBsAg) without aluminum were prepared by spray-freeze drying in the presence of either inulin or a combination of dextran and trehalose. The stability of HBsAg in the amorphous powder formulations was strongly improved during storage both at room temperature and at an elevated temperature (60 °C), compared to a liquid plain and an aluminum hydroxide adjuvanted HBsAg formulation. Immunogenicity studies in mice showed that reconstituted powder formulations induced higher IgG immune responses after intramuscular administration than those induced after administration of unprocessed plain antigen. Although the immune response was not as high as after administration of aluminum adjuvanted HBsAg, the immune response to the reconstituted vaccines shifted towards a more balanced Th1/Th2 response compared to the aluminum containing HBsAg formulation.
Hepatitis B surface antigen; Stabilization; Powder formulation; Inulin; Dextran; Trehalose
Yibin Deng, Roman Mathaes, Gerhard Winter, Julia Engert
Epidermal powder immunisation (EPI) is being investigated as a promising needle-free delivery methods for vaccination. The objective of this work was to prepare a nanoparticles-in-microparticles (nano-in-micro) system, integrating the advantages of nanoparticles and microparticles into one vaccine delivery system for epidermal powder immunisation. Cationic mesoporous silica nanoparticles (MSNP-NH2) were prepared and loaded with ovalbumin as a model antigen. Loading was driven by electrostatic interactions. Ovalbumin-loaded silica nanoparticles were subsequently formulated into sugar-based microparticles by spray-freeze-drying. The obtained microparticles meet the size requirement for EPI. Confocal microscopy was used to demonstrate that the nanoparticles are homogeneously distributed in the microparticles. Furthermore, the silica nanoparticles in the dry microparticles can be re-dispersed in aqueous solution showing no aggregation. The recovered ovalbumin shows integrity compared to native ovalbumin. The present nano-in-micro system allows (1) nanoparticles to be immobilized and finely distributed in microparticles, (2) microparticle formation and (3) re-dispersion of nanoparticles without subsequent aggregation. The nanoparticles inside microparticles can (1) adsorb proteins to cationic shell/surface voids in spray-dried products without detriment to ovalbumin stability, (2) deliver antigens in nano-sized modes to allow recognition by the immune system.
Nanoparticles; Microparticles; Mesoporous silica; Vaccination; Nano-in-microparticle system
S. M. Olhero, Ajay Kaushal and J. M. F. Ferreira
The present paper reports the overall benefits of freeze granulation for enhancing the properties of zirconium tin titanate Zr0.8Sn0.2TiO4 (ZST) ceramics in the total absence of sintering additives. The ZST powder was synthesized by solid state reaction and attrition milled in ethanol for 10 h. This starting non-granulated powder (NG-ZST), without and with 1 wt% ZnO as sintering additive, was used to consolidate green bodies by dry pressing. The pure ZST powder was also dispersed in aqueous media to obtain stable suspensions with high solid loadings. Free flowing spherical homogeneous granules were prepared by freeze granulation and used to consolidate ZST green bodies by dry pressing (FG-ZST). The effects of processing variables and sintering temperature (1300–1450 °C) on densification and on the structural, mechanical and electrical properties of ZST ceramics were systematically investigated. Our study clearly reveals the superior properties of FG-ZST ceramics, which derive from an enhanced sintering behaviour associated with the absence of sintering additives.
Spray-Freeze-Drying approach for soluble coffee processing and its effect on quality characteristics
S. Padma Ishwarya, C. Anandharamakrishnan
The suitability of Spray-Freeze-Drying (SFD) technique for soluble coffee processing was evaluated. The resultant product characteristics were compared against its spray-dried (SD) and freeze-dried (FD) counterparts. SFD and FD coffee powders exhibited a comparable aroma profile as indicated by the electronic nose analysis. SFD resulted in higher volatile retention (93%) than FD (77%) and SD (57%), as inferred from GC–MS analysis. SFD coffee showed instantaneous solubility due to its highly porous nature as observed in morphology studies. SFD coffee depicted monomodal particle size distribution with mean diameter (91.1 μm) ranging between SD (50.41 μm) and FD (636.8 μm) particles. SFD resulted in higher free (ρB, 0.612 g/mL) and tapped (ρT, 0.679 g/mL) bulk densities of the product against SD (ρB: 0.328 g/mL; ρT: 0.388 g/mL) and FD (ρB: 0.345 g/mL; ρT: 0.361 g/mL). SFD coffee exhibited free flowing characteristics as indicated by its Hausner ratio (1.11) and Carr index (10%).
Soluble coffee; Spray-Freeze-Drying; Volatile retention; Morphology; Bulk density; Tap density
Dalia R. Abd El-Hafiz, Mohamed A. Ebiad
Ultra-fine Ce–Co and Cox/Ce–La (x = 4 and 10%) solid solutions (SS) were prepared for the first time by spray freezing technology, and evaluated in bio-ethanol steam reforming reaction for H2 production. The catalysts were characterized by DLS, XRD, BET and TEM, in order to reveal the structure activity relationship. It was shown that, the addition of La3+ cation to Ce–Co catalyst lead to 100% ethanol conversion at lower reaction temperature (300 °C). Hydrogen selectivity was higher on Ce–Co catalyst than on Cox/Ce–La and increase by increase Co content. Moreover, Cox/Ce–La catalysts provided highest deactivation resistant during 15 h. Characterization of spent catalysts revealed that, the addition of La as a promoter to Ce–Co catalyst preventing sintering at high temperatures. TGA analysis indicates the formation of very small amounts of amorphous carbon on Co10/Ce–La catalyst, while CNT was formed on Ce–Co which responsible for deactivation processes. Both oxygen vacancy and La2O2CO3 acted as carbon scavengers during ESR reaction over Cox/Ce–La.
Cobalt; Ceria; Lanthanum; Nano-structures; Spray freeze drying; Hydrogen production
