China
Africa
Explore chapters and articles related to this topic
Towards the Importance of Fenugreek Proteins
Published in Dilip Ghosh, Prasad Thakurdesai, Fenugreek, 2022
Drying using spray, freeze, and vacuum oven methods, etc., as a tool for preservation, is the common step of protein isolates’ processing. Although accompanied with more limited changes in proteins’ attributes, freeze drying is less used on an industrial scale owing to the time and energy required. Spray drying, in contrast, is more favored in the industry because of its speed and some characteristics in its final products, including smaller and more uniform particles. Feyzi et al. (2018b) found that while vacuum oven drying resulted in less Lys, Met, and total amino acids content in fenugreek protein isolate, no considerable difference would occur between freeze and spray dried samples. Such phenomena occur as a result of Maillard and oxidation during prolonged vacuum oven procedure. Moreover, results of FTIR proved that freeze and spray drying methods resulted in more retention of α-helix structures compared with vacuum oven procedure. However, bands related to β-sheet structures were more profound in spray dried samples than freeze dried ones, probably due to conversion of α-helix structures to β-sheet ones during the cooling step after heating. Finally, no protein aggregation was detected for three dried fenugreek protein samples based on SDS-PAGE and FTIR results. These findings coincided with those reported about various grass pea protein isolates dried using vacuum oven and freeze drying methods (Feyzi et al., 2018b).
Advances in Wet Granulation of Modern Drugs
Published in Dilip M. Parikh, Handbook of Pharmaceutical Granulation Technology, 2021
Bing Xun Tan, Wen Chin Foo, Keat Theng Chow, Rajeev Gokhale
Although freeze-drying is the mainstay technology and represents the gold standard for stabilization of therapeutic protein formulations with a long line of established commercial products [57], it produces low-density powders, which owing to their high porosity and dispersibility are more suited to be reconstituted for parenteral delivery or to be administered via inhalation. For the processing of dry powders into oral dosage forms, a granulation step is required to impart suitable powder properties to lyophilized powders, namely, flow and compressibility. Dry granulation methods such as slugging are typically employed to minimize the degradation of proteins when exposed to moisture.
Drug Nanocrystals
Published in Carla Vitorino, Andreia Jorge, Alberto Pais, Nanoparticles for Brain Drug Delivery, 2021
M. Ermelinda S. Eusébio, Ricardo A. E. Castro, Joäo Canotilho
A solution containing API and surfactant is sprayed into a cryogenic liquid. The resulting frozen solid particles are collected and lyophilised [63, 101, 102]. Freeze-drying is used to obtain dry powders which can be used in formulations with enhanced shelf lives [103]. Amorphous nanostructures tend to result, as observed in experiments conducted for danazol, in which 100 nm diameter particles were obtained, using a small amount of surfactant [63].
The development and application of a novel reagent for fixing red blood cells with glutaraldehyde and paraformaldehyde
Published in Hematology, 2023
Xinyang Li, Miyang Li, Yuhong Wang, Shengbao Duan, Hongmei Wang, Yong Li, Zhonghe Cai, Ruiyao Wang, Shuang Gao, Yan Qu, Tianxia Wang, Fei Cheng, Tiemei Liu
Red blood cell reagents for reverse typing detection are typically preserved using low temperature storage, freeze-drying, and storage at 4°C [8]. However, each of the three methods listed above has flaws [9–13]. Low-temperature freezing (typically −80°C) requires an ultra-low-temperature refrigerator or a liquid nitrogen tank, which consumes a significant amount of liquid nitrogen or electricity and is challenging to transport [14–16]. The process of rewarming and washing to remove cryoprotectants (typically high-concentration glycerin) is complex, time-consuming, and laborious, and it is difficult to ensure that cryoprotectants can be added and removed without excessive red blood cell loss at a reasonable cost and in a reasonable amount of time [17]. Freeze-drying requires the use of specialized freeze-drying equipment and a freeze-drying protective agent, as well as a labor-intensive and time-consuming operation process [18,19]. Preserving commercial red blood cell reagents at 4°C is a common method that is utilized in clinical practice. However, to date, the shelf life of commercial red blood cell reagents used in ABO reverse typing tests is only 2–3 months under 4°C. After more than three months, commercial red blood cell reagents become hemolyzed easily, and the antigen stability on the surface of commercial red blood cell reagents is poor, which is not conducive to ABO reverse typing test results.
The effect of short-term cryopreservation on the properties and functionality of platelet-rich plasma
Published in Platelets, 2023
Maider Beitia, Diego Delgado, Jon Mercader, Irene Gimeno, João Espregueira-Mendes, Beatriz Aizpurua, Mikel Sánchez
In recent years, several studies have been carried out to analyze different PRP preservation conditions. These studies revealed that room temperature was only valid for the preservation of PRP for a maximum of one week and would not be valid for longer periods.7–9 Meanwhile, freeze-drying facilitates the optimal preservation of platelets and growth factors for long periods of time in vitro10 and in vivo.11 However, freeze-drying involves the use of specific equipment and higher costs. Finally, there is the possibility of freezing PRP, which is simpler, cheaper, and more feasible in clinical practice. Overall, the studies performed comparing fresh and frozen PRP are short-term focused and showed that, although the platelet and plasma growth factor profile may vary, bioactivity remains at similar levels in both groups in in vitro12,13 and in vivo14 research works. Therefore, no long-term studies have been performed, except for one 6-month study with equine PRP, where it was reported that PRP can be frozen at −80ºC for 1 month to keep the concentrations of TGF-B and IGF-1 intact.15
Nanocrystals based pulmonary inhalation delivery system: advance and challenge
Published in Drug Delivery, 2022
Pengfei Yue, Weicheng Zhou, Guiting Huang, Fangfang Lei, Yingchong Chen, Zhilin Ma, Liru Chen, Ming Yang
The process of freeze-drying is to first freeze the liquid solution or suspension under atmospheric pressure and then heat it under vacuum in order to remove ice crystals by sublimation. Finally, the high-porosity powder with low moisture content was obtained. The freeze-drying process consists of three steps: freezing, primary drying, and secondary drying (Siow et al., 2016). Freeze-drying and spray-drying are most commonly used techniques for solidification of nanosuspension as they are easily applied in practice, their scale up production and high industrial acceptability. In order to form inhalable microparticles (NP-agglomerates), El-Gendy et al. (2009) used freeze-drying to solidify the nanosuspension, which was obtained through a controlled flocculation process (protocol under the name NanoClustersΤΜ, owned by Savara Pharmaceuticals, Austin, TX). Budesonide nanocrystals-agglomerates prepared by this method showed enhanced dissolution rate when compared with the raw drug, with an MMAD of 2.1 ± 1.8 µm (mean standard deviation) in terms of aerosolization, which is aided by the penetration of the particles deeper into the lungs.