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Antiviral Nanomaterials as Potential Targets for Malaria Prevention and Treatment
Published in Devarajan Thangadurai, Saher Islam, Charles Oluwaseun Adetunji, Viral and Antiviral Nanomaterials, 2022
Kantrol Kumar Sahu, Sunita Minz, Madhulika Pradhan, Monika Kaurav, Krishna Yadav
After that, a large quantity of aqueous medium is applied to the emulsion (o/w) to enable the solvent to diffuse into the aqueous phase and form nanoparticles. Crossflow filtration is used to eliminate the salting-out agent and solvent. This method offers various advantages, including high efficiency, ease of scale-up, and utility for heat-sensitive substances. The disadvantages include the need to extensively wash NPs and the limited applicability for lipophilic drugs.
Membrane Filtration Technology in Plasma Exchange*
Published in James L. MacPherson, Duke O. Kasprisin, Therapeutic Hemapheresis, 2019
Robert R. Stromberg, R. Alan Hardwick, Leonard I. Friedman
In plasma exchange, the process is called “cross-flow” filtration, which differs significantly from “dead-end” filtration. As shown in Figure 1, in cross-flow filtration the blood passes parallel to the surface of the membrane, while the substances to be removed from the blood pass perpendicularly through the membrane into the filtrate compartment. Filtration efficiency is governed by many parameters. These include: blood flow rate, pressure difference across the membrane, geometry of the blood flow path, composition and physical structure of the membrane, and the physicochemical nature of the substances that pass through the membrane. In addition to these parameters, consideration must be given to module biocompatibility, sterilizability, and cost. Filtration module operating conditions must be such that cellular and noncellular damage to the blood is avoided.
Biologic Drug Substance and Drug Product Manufacture
Published in Anthony J. Hickey, Sandro R.P. da Rocha, Pharmaceutical Inhalation Aerosol Technology, 2019
Ajit S. Narang, Mary E. Krause, Shelly Pizarro, Joon Chong Yee
In this step, the cell culture harvest, consisting of target protein in the dissolved state and suspended solids such as cells and cell debris, is subjected to sedimentation, centrifugation, deep bed or depth filtration, and one or more steps of microfiltration. Sedimentation and centrifugation: Gravitational and centrifugal rotational settling of particulate matter allows initial separation of most of the particles from the fluid for initial clarification.Depth filtration or deep bed filtration consists of a porous filtration medium that retains particles throughout the medium, rather than just on the surface. This process is particularly suitable for fluids with high particle load since the filter can retain a large mass of particles before getting clogged. Depth filters provide high surface area and adsorptive surface. In addition to adsorbing impurities from cell culture supernatants, depth filters can also remove viruses (Yigzaw et al. 2006).Microfiltration involves passing the fluid through a specific pore size membrane to effect removal of microorganisms and suspended particles. Suspended particles are retained (“retentate”) on the feed side of the membrane, while the dissolved liquids, including the protein of interest, passes through (“permeate”). A cross-flow filtration process, where the fluid is moved in a direction tangential to the membrane surface, is preferred compared to the dead-end filtration (where the fluid is forced through the membrane surface at a dead end to the direction of flow).
Virus-like particle-based nanocarriers as an emerging platform for drug delivery
Published in Journal of Drug Targeting, 2023
Bingchuan Yuan, Yang Liu, Meilin Lv, Yilei Sui, Shenghua Hou, Tinghui Yang, Zakia Belhadj, Yulong Zhou, Naidan Chang, Yachao Ren, Changhao Sun
To produce VLPs for clinical use, purification is required. The main purpose of purification is to remove host cell proteins and process-derived impurities from the VLP concentrate [129]. Super-centrifugal purification methods in sucrose or CsCl gradients are usually sufficient to obtain suitable VLPs for subsequent application, especially on a laboratory-scale or using small-scale processes. Hillebrandt et al. reported a new purification method known as crossflow filtration [143]. The application of a super-centrifugal method is limited in industrial production because of the risk of VLP aggregation, high labour intensity and the lack of scalability [138]. Therefore, it is necessary to purify VLPs using special chromatography techniques rather than super-centrifugation. Depending on the VLP properties, different ion exchange-, affinity- and size-exclusion columns can be used for purification. Diafiltration and tangential flow filtration are also used to scale up VLP production.
Long-acting injectable formulation technologies: challenges and opportunities for the delivery of fragile molecules
Published in Expert Opinion on Drug Delivery, 2022
Andrea Gonella, Sylvestre Grizot, Fang Liu, Adolfo López Noriega, Joël Richard
Sterilization strategies are product dependent and differ based on the type of protein and formulation. However, some key points can be highlighted considering dried formulations of PLGA microparticles, implants, and ISFDs. As for peptides, sterilization by filtration is not possible with microparticle-based products but can be envisioned with ISFDs, a fact which further reinforces the interest around the use of these types of formulations. However, special attention should be paid when scaling-up filtration methods: during cross-flow filtration, for example, proteins may be exposed to high shear rates while passing through membranes, leading to potential denaturation. The passage through pumps and valves may also cause microcavitation, leading to the formation of bubbles, which, upon collapse, create microscopic regions at high local temperature and pressure which may contribute to the generation of hydrogen and hydroxyl radicals and lead to the formation of protein aggregates and particles [87,88].
Advances in influenza virus-like particles bioprocesses
Published in Expert Review of Vaccines, 2019
Laurent Durous, Manuel Rosa-Calatrava, Emma Petiot
Membrane-based processes of clarification emerged as a reliable alternative to centrifugation methods, especially for large production volume. Indeed, they present increased scalability and better control of the shear stress applied to the product [84]. Normal-flow filtration (NFF, or dead-end filtration) and tangential-flow filtration (TFF, or cross-flow filtration) with micrometer scale cutoff filters are used. Depending on the filter’s material and their dimensional arrangement, depth filters can advantageously partially absorb HCP and DNA [12,84]. Thus, several academic and industrial studies applied membrane-based processes for clarification. 0.2 µm NFF sterile microfiltration was sued for bulk clarification of influenza-VLP bioreactor batches [30,43,64] and Redbiotec implemented disposable depth filters thus reaching 90% recovery of HA antigens [58] (Table 2).