Microstructure of spray freezing dried powders affected by the presence of inert particles

2020 ◽  
Vol 16 (7) ◽  
Author(s):  
Fan Zhang ◽  
Linsong Wang ◽  
Xiaoyu Ma ◽  
Qing Xu ◽  
Wei Tian ◽  
...  
Keyword(s):  
Freeze Drying ◽  
Great Influence ◽  
Freezing Process ◽  
Drying Time ◽  
Dry Powders ◽  
Spray Freezing ◽  
Spray Freeze Drying ◽  
The Difference ◽  
Droplet Morphology ◽  
Drying Chamber

AbstractSpray freeze-drying is a process to directly produce high quality powders with short drying time. The difference of microstructures has a great influence on the physical properties of powders. However, during the spray freeze-drying process, the freezing degree of droplets in the drying chamber will change the product structure and affect the powder quality. In this study, the surface structure and morphology of dry powders were observed using scanning electron microscopy. The formation mechanism of droplet morphology during spray freeze-drying was analyzed. The results show that the rapid freezing process can produce finer microstructures.

Bulk Dynamic Spray Freeze-Drying Part 2: Model-Based Parametric Study for Spray-Freezing Process Characterization

2019 ◽  
Vol 108 (6) ◽  
pp. 2075-2085 ◽  
Author(s):  
Israel B. Sebastião ◽  
Bakul Bhatnagar ◽  
Serguei Tchessalov ◽  
Satoshi Ohtake ◽  
Matthias Plitzko ◽  
...  
Keyword(s):  
Parametric Study ◽  
Freeze Drying ◽  
Freezing Process ◽  
Model Based ◽  
Process Characterization ◽  
Spray Freezing ◽  
Spray Freeze Drying

scholarly journals The effect of excipients on the stability and aerosol performance of salmon calcitonin dry powder inhalers prepared via the spray freeze drying process

2016 ◽  
Vol 66 (2) ◽  
pp. 207-218 ◽  
Author(s):  
Narges Poursina ◽  
Alireza Vatanara ◽  
Mohammad Reza Rouini ◽  
Kambiz Gilani ◽  
Abdolhossein Rouholamini Najafabadi
Keyword(s):  
Salmon Calcitonin ◽  
Freeze Drying ◽  
Tween 80 ◽  
Drying Process ◽  
Dry Powders ◽  
Aerosol Performance ◽  
Inhalation Delivery ◽  
Spray Freeze Drying ◽  
The Stability ◽  
Structurally Stable

Abstract Spray freeze drying was developed to produce dry powders suitable for applications such as inhalation delivery. In the current study, the spray freeze drying technique was employed to produce inhalable salmon calcitonin microparticles. Effects of the carrier type, concentration of hydroxyl propyl-β-cyclodextrin and the presence of Tween 80 on the chemical and structural stability, as well as on the aerosol performance of the particles were investigated. The results indicated that hydroxyl propyl-β-cyclodextrin had the most important effect on the chemical stability of the powder and strongly increased its stability by increasing its concentration in the formulation. Chemically stable formulations (over 90 % recovery) were selected for further examinations. Fluorescence spectroscopy and circular dichroism suggested that the formulations were structurally stable. Aerosol performance showed that the Tween-free powders produced higher fine particle fraction values than the formulations containing Tween (53.7 vs. 41.92 % for trehalose content and 52.85 vs. 43.06 % for maltose content).

Porous and highly dispersible voriconazole dry powders produced by spray freeze drying for pulmonary delivery with efficient lung deposition

2019 ◽  
Vol 560 ◽  
pp. 144-154 ◽  
Author(s):  
Qiuying Liao ◽  
Long Yip ◽  
Michael Y.T. Chow ◽  
Shing Fung Chow ◽  
Hak-Kim Chan ◽  
...  
Keyword(s):  
Freeze Drying ◽  
Pulmonary Delivery ◽  
Lung Deposition ◽  
Dry Powders ◽  
Spray Freeze Drying

Development of a Compact Vacuum Freeze Drying for Jelly Fish (Schypomedusae)

2012 ◽  
Vol 58 (2) ◽  
Author(s):  
M. Idrus Alhamid ◽  
M. Yulianto ◽  
Nasruddin M. ◽  
Engkos A. Kosasih
Keyword(s):  
Heat Loss ◽  
Freeze Drying ◽  
Moisture Ratio ◽  
Cold Trap ◽  
Chamber Pressure ◽  
Internal Cooling ◽  
Drying Process ◽  
Drying Time ◽  
Chamber Temperature ◽  
Drying Chamber

A new design of a vacuum freeze drying with internal cooling and heater from condenser’s heat loss was built and tested. The dryer was used to dry jelly fish (scyphomedusae) to study the effect of drying parameter such as temperature within the drying chamber on mass losses (evaporation) during freezing stage and moisture ratio at the end of drying process and also the drying rate of vacuum drying process. The cold trap temperature rise in when activated the heating from condenser’s heat loss. The midili thin layer mathematical drying model was used to estimate and predict the moisture ratio curve base on different drying chamber temperature. The result of this experiment show that mass loss during freezing stage decreased with a decrease in drying chamber temperature with constant pressure. Drying time reduced with an increase in drying temperature. Drying chamber temperature decreasing has a result pressure saturation of material lower than drying chamber pressure have an effect mass transfer should not occurs.

Inhalable clarithromycin liposomal dry powders using ultrasonic spray freeze drying

2017 ◽  
Vol 305 ◽  
pp. 63-70 ◽  
Author(s):  
Tiantian Ye ◽  
Jiaqi Yu ◽  
Qiuhua Luo ◽  
Shujun Wang ◽  
Hak-Kim Chan
Keyword(s):  
Freeze Drying ◽  
Dry Powders ◽  
Ultrasonic Spray ◽  
Spray Freeze Drying

Parameter Optimization of Vacuum Freeze-Drying Processing on Tan Lamb

2014 ◽  
Vol 513-517 ◽  
pp. 4281-4284
Author(s):  
Chen Ji ◽  
Yan Li Fan ◽  
Gui Shan Liu ◽  
Wei Wang ◽  
Rui Ming Luo
Keyword(s):  
Freeze Drying ◽  
Orthogonal Design ◽  
Chamber Pressure ◽  
Drying Process ◽  
Quadratic Regression ◽  
Plate Temperature ◽  
Drying Time ◽  
Material Thickness ◽  
Heating Plate ◽  
Drying Chamber

In this paper, the effects of drying chamber pressure, heating plate temperature and material thickness on the drying time of Tan lamb in vacuum freeze-drying process were studied using quadratic regression orthogonal design. The results showed that the drying time was significantly affected by drying chamber pressure, heating plate temperature and material thickness as well as the interaction of heating plate temperature and material thickness. The optimized parameters were drying chamber pressure 27.9 Pa, heating plate temperature 47.9°C and material thickness 4.3 mm. On these parameters, the drying time was 4.3 h.

scholarly journals Water Vapor Pathways during Freeze-Drying of Foamed Product Matrices Stabilized by Maltodextrin at Different Concentrations

Processes ◽  
2020 ◽  
Vol 8 (11) ◽  
pp. 1463
Author(s):  
Peter Kubbutat ◽  
Annika Tauchnitz ◽  
Ulrich Kulozik
Keyword(s):  
Water Vapor ◽  
Freeze Drying ◽  
Structural Changes ◽  
Vapor Transport ◽  
Water Vapor Transport ◽  
Transport Mechanisms ◽  
Drying Time ◽  
Pathway Length ◽  
Drying Chamber

This study aimed to identify the water-vapor transport mechanisms through an aerated matrix during microwave freeze-drying. Due to the larger surface area and lower water vapor transport resistance of an aerated product compared to the solution, foam structures dry faster. Different foam structures were produced with different maltodextrin (MD) concentrations (10–40%) as a foam-stabilizing agent. Depending on the initial viscosity of the solution prior to foaming, the samples differed in overrun (41–1671%) and pore size (d50 = 58–553 µm). Experiments were partially performed in a freeze-drying chamber of a light microscope to visualize structural changes in-situ. Different mechanisms were identified explaining the accelerated drying of foams, depending on the MD concentration, above or below 30%. At lower MD concentration, high overruns could be produced prior to freezing with big bubbles and thin lamellae with short diffusion pathway length. At 40% MD concentration, the viscosity was too high to integrate much air into the product. Therefore, the foam overrun was low and the bubble size small. Under these conditions, the water vapor generates high pressure, resulting in the formation of channels between bubbles, thus creating the pathways with low resistance for a very fast water vapor mass transfer. In addition, microwave freeze-drying experiments using a pilot plant unit were conducted to validate the findings of the freeze-drying microscope. A reduction of the drying time from 150 min (10% MD) to 78 min (40% MD) was achieved.

scholarly journals Influence of Freezing Parameters on the Formation of Internal Porous Structure and Its Impact on Freeze-Drying Kinetics

Processes ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 1273
Author(s):  
Patrick Levin ◽  
Vincent Meunier ◽  
Ulrich Kessler ◽  
Stefan Heinrich
Keyword(s):  
Internal Structure ◽  
Freeze Drying ◽  
Crystal Size ◽  
Single Layer ◽  
Drying Kinetics ◽  
Freezing Process ◽  
Drying Time ◽  
Air Blast ◽  
Temperature Cycles ◽  
Freeze Dried

The main objective of this study was firstly to investigate the influence of freezing process parameters on the formation of the internal structure of frozen coffee granules. It was investigated how these frozen internal structures affect the drying kinetics during freeze-drying. A design of experiment study was carried out using the response surface method to quantify the influence of the freezing step that occurs in a scraped surface heat exchanger (SSHE). Therefore, the coffee extract at a concentration of 30% w/w is entering the SSHE as a liquid and gets partially crystallized up to a weight-based ice content of 0.364. During this step, the influence of factors like cooling temperature, scraper rotation speed and temperature cycles on ice crystal structure was investigated. In a second freezing step, the influence of freezing rates during hardening of the product by air-blast freezing is investigated, where the freezing rate is significantly affected by the cake thickness. The produced frozen granules were freeze-dried in single layer experiments. During drying the influence of internal structure on the drying kinetics was investigated. Results show that all factors have a significant impact on structure parameters for 30% w/w coffee solutions. A lower degree of supercooling during freezing in an SSHE, a higher number of temperature cycles (2 to 8 times) and lower freezing rates during hardening (2 °C/min to 10 °C/min) were leading to increased crystal size. This increase accelerates the primary drying rate and decreases the total drying time. A higher number of temperature cycles leads to a significant increase of crystal size and therefore larger pore size at the end of the primary drying. Furthermore, in combination with temperature cycles in the SSHE, it was found that high freezing rates during air blast freezing generally lead to a second nucleation step of ice crystals.

scholarly journals Intratracheal inoculation of AHc vaccine induces protection against aerosolized botulinum neurotoxin A challenge in mice

npj Vaccines ◽  
2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Changjiao Gan ◽  
Wenbo Luo ◽  
Yunzhou Yu ◽  
Zhouguang Jiao ◽  
Sha Li ◽  
...  
Keyword(s):  
Bronchoalveolar Lavage ◽  
Clostridium Botulinum ◽  
Freeze Drying ◽  
Botulinum Neurotoxin ◽  
Secretory Iga ◽  
Immune Protection ◽  
Dry Powder ◽  
Botulinum Neurotoxin A ◽  
Spray Freeze Drying

AbstractBotulinum neurotoxin (BoNT), produced by Clostridium botulinum, is generally known to be the most poisonous of all biological toxins. In this study, we evaluate the protection conferred by intratracheal (i.t.) inoculation immunization with recombinant Hc subunit (AHc) vaccines against aerosolized BoNT/A intoxication. Three AHc vaccine formulations, i.e., conventional liquid, dry powder produced by spray freeze drying, and AHc dry powder reconstituted in water are prepared, and mice are immunized via i.t. inoculation or subcutaneous (s.c.) injection. Compared with s.c.-AHc-immunized mice, i.t.-AHc-immunized mice exhibit a slightly stronger protection against a challenge with 30,000× LD50 aerosolized BoNT/A. Of note, only i.t.-AHc induces a significantly higher level of toxin-neutralizing mucosal secretory IgA (SIgA) production in the bronchoalveolar lavage of mice. In conclusion, our study demonstrates that the immune protection conferred by the three formulations of AHc is comparable, while i.t. immunization of AHc is superior to s.c. immunization against aerosolized BoNT/A intoxication.

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