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Value-Added Products and Bioactive Compounds from Fruit Wastes
Published in Megh R. Goyal, Arijit Nath, Rasul Hafiz Ansar Suleria, Plant-Based Functional Foods and Phytochemicals, 2021
Ranjay Kumar Thakur, Rahel Suchintita Das, Prashant K. Biswas, Mukesh Singh
Supercritical fluid extraction (SFE) is performed by applying temperature and pressure that transforms the gas in the supercritical fluid to a point, where the gas and liquid phases cannot be distinguished. The extraction is fast, selective without any need of further cleaning and can be performed with small samples [123]. It is a mass transfer operation, with convection occurring between the solid surface and fluid phase [157]. The steps in the process are: (a) solubilization of the compounds, which are in the solid matrix and subsequently, and separation in the supercritical solvent, (b) the solvent passes through the packed bed and extracts solubilized compounds from the matrix, and (c) solvent then exits the extractor and by pressure reduction and temperature increase, it transforms to a solvent-free extract [158].
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
High-gravity precipitation can be operated in two modes, depending on the liquid streams distributing into the rotating packed bed (see Fig. 7.4): high-gravity antisolvent precipitation (HGAP) or high-gravity reactive precipitation (HGRP). In HGAP, two liquid streams (drug solution and antisolvent) are mixed at the centre of a rotating packed bed, where the mixture is subjected to high gravity due to centrifugal forces. The mixture is forced to pass the packed bed before leaving the reactor [77, 111, 114–117]. This method normally uses organic solvents. In the alternative HGRP process, which is applied to acidic drugs for instance, a basic aqueous drug solution and an acid aqueous solution are mixed, generating, in situ, the acidic form of the drug. Very recently, Zhang et al and Kuang et al. achieved sizes smaller than 100 nm with both approaches [74, 78].
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
An alternative to expanded/fluidized bed capture without clarification is the use of packed bed of large size beads. In this case, the cell culture medium is made to pass down a packed bed of high-efficiency large diameter particles, so that both the cells and the liquid can pass through while the target protein is adsorbed on the adsorbent. This process is less sensitive to feed viscosity, but also less efficient due to the lower surface area of large size adsorbent particles.
Mechanics of tablet formation: a comparative evaluation of percolation theory with classical concepts
Published in Pharmaceutical Development and Technology, 2019
Saurabh M. Mishra, Bhagwan D. Rohera
The elucidation of processes underlying compression and consolidation of powders has been a challenge for a long time. It gets much more complex since theories proposed to explain the mechanical behavior of continuum bodies fail to satisfactorily explain the behavior of particulate bodies (Holman 1991). The application of percolation theory in the present work is based on the critical observation of powder compression and compaction, and various stages involved in the formation of a tablet. During the tableting process, at zero pressure, the die contains loosely packed powder particles or granules. At the onset of compression, particles within loosely packed bed undergo some rearrangement in their packing state reducing particle-particle contact distance (Leuenberger and Rohera 1986a). Further, with increasing compression load, depending on their properties, elastic/plastic deformation or fracture of particles occurs. Thus the process of tablet formation can be defined in two stages of relative densities. Initially, at low compression pressure, the transition of a loosely packed bed to a loose compact occurs which is mechanically unstable. Further, with an increase in the compression pressure, the loose compact transitions to a dense compact which is mechanically stable. In terms of percolation phenomenon, the transition of loosely packed bed to a dense compact can be expressed as bond percolation threshold, ρcb, and site percolation threshold, ρcs, representing the formation of the loose and the dense compact, respectively (Leuenberger and Leu 1992).
Developments and opportunities in continuous biopharmaceutical manufacturing
Published in mAbs, 2021
Ohnmar Khanal, Abraham M. Lenhoff
Following mAb capture, viral inactivation is typically carried out in batch processing by holding the low-pH Protein A eluate in a large tank for approximately 1 hr. This can also be performed continuously, as shown recently using a continuous reactor with a narrow RTD, where significant viral inactivation was observed after just 15 mins.46 To ensure an appropriate minimum residence time, the FDA recommends evaluating the RTD for continuous viral inactivation.85 To this end, three viral inactivation reactor designs have been proposed: a coiled flow inverter,86,87 a tubular reactor called jig-in-a-box,88,89 and a packed-bed reactor46,47 (Figure 1c). Radial mixing is enhanced in the first two designs due to the presence of helical structures and alternating 270° turns, respectively. In the packed-bed reactor, nonporous particles ensure a narrow RTD. Collectively, these advances demonstrate that viral inactivation may be adapted for continuous manufacturing. However, challenges remain to be overcome in the integration of continuous viral inactivation reactors with multicolumn chromatography methods that process sample periodically.46 The variation in the pH and concentration of the affinity eluate over time may also hinder the performance of continuous viral inactivation, requiring an additional hold step.46 In addition to viral inactivation, viral filtration may also be carried out continuously90 under a lower pressure over an extended duration. Filters appropriate for such an operation must be carefully chosen,90 and multiple filter set-ups may be considered.
On the potential of micro-flow LC-MS/MS in proteomics
Published in Expert Review of Proteomics, 2022
Yangyang Bian, Chunli Gao, Bernhard Kuster
Chromatographic columns are at the center of LC separations, and high-quality column performance is also essential in proteomics because of the vastness in molecular complexity of a proteomic sample. Nano-LC separations are very well established, and columns for this flow range will not be specifically discussed in this review. Currently, three types of columns are used in the literature: (1) packed-bed particle; (2) monolithic; and (3) microchip-based pillar arrays (μPAC). Table 1 provides an overview of the columns used in capillary-, micro- and analytical-flow LC-MS/MS. Packed-bed columns are most broadly used and these can be categorized as ‘core-shell’ and ‘fully porous’ materials. As a consequence of narrower peaks, columns packed with core-shell particles usually demonstrate higher sensitivity. The surface area of core-shell particles, however, is much lower than that of fully-porous particles, which results in a reduced sample loading capacity. Therefore, columns packed with fully porous materials may be more suitable for samples with extreme protein abundance differences, e.g. plasma or other body fluids. Monolithic columns are interesting as, even at elevated flow rates, these feature high separation efficiency and low back pressure but also have limited loading capacity. The Huber laboratory fabricated micropellicular poly(styrene/divinylbenzene) (PS/DVB) reversed-phase monolithic columns that enable the rapid and highly efficient separation of peptides and proteins [81–83]. This technology was later commercialized under the names PepSwift/ProSwift and various internal diameter columns are available. Monolithic columns have usually been adopted for intact protein analysis and top-down proteomics; two areas that are not covered in this review [84–87].