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Validation of Recovery and Purification Processes
Published in James Agalloco, Phil DeSantis, Anthony Grilli, Anthony Pavell, Handbook of Validation in Pharmaceutical Processes, 2021
Liquid–liquid extraction occurs with the partitioning of solutes between two immiscible phases. Because few proteins are soluble, let alone stable, in organic solvents, the systems of most interest for biotherapeutics are those created by the addition of certain pairs of hydrophilic polymers to aqueous solutions, causing a phase separation without the presence of any hydrophobic solvent.28 One common system is created by the addition of both polyethylene glycol (PEG) and dextran, the PEG-rich phase being less dense than the dextran-rich phase. Aqueous two-phase systems can also be formed with PEG and various salts. Most proteins, as well as particulate matter and cellular debris, partition into the dextran-rich phase. A breakthrough in the usefulness of phase partitioning came with the attachment of ligands, mainly dyes, to PEG, which attracts specific proteins into the PEG-rich phase in a technique referred to as “affinity partitioning.” By arranging the partitioning to occur in multiple stages, using classical countercurrent distribution, high product purity and yield can be achieved.29
Aqueous Two-Phase Separations
Published in Juan A. Asenjo, Separation Processes in Biotechnology, 2020
Per-Åke Albertsson, Göte Johansson, Folke Tjerneld
Aqueous two-phase systems are useful for separation of a wide range of water-compatible substances (from peptides to cells). The selectivity of the separation normally increases with the size of the partitioned molecules or particles. The partition and separation capacity can be influenced in a number of ways, including electric charge, hydrophobicity, or specific ligand binding. Because of the simpleness in operation and high capacity, aqueous two-phase systems are well suited for large-scale purification of biomaterials such as enzymes and other specific proteins.
Response surface methodology for optimisation of glycyrrhizic acid extraction from Glycyrrhiza glabra in the aqueous two-phase system
Published in Indian Chemical Engineer, 2023
Kavita J. Lanjekar, Virendra K. Rathod
PEG 4000-Sodium citrate ATPS was substantiated to be a successful alternative to extract glycyrrhizic acid from Glycyrrhiza glabra (Licorice). The important parameters affecting the separation of glycyrrhizic acid in an ATPS were PEG molecular weight, PEG concentration, salt concentration, and pH and were optimised by a Central Composite Design. Factor A (PEG molecular weight) had a significant effect on the yield of GA. The predicted model was validated due to the close similarity between experimental and predicted responses. The statistical technique, i.e. Response Surface Methodology, has been successfully utilised for the improvement of the partitioning of glycyrrhizic acid to the PEG-rich top phase in ATPS. Moreover, the ATPS method was more efficient than the conventional Soxhlet extraction based on process time, energy, and solvent requirement, along with higher purity of GA. Besides, the Aqueous Two-Phase System can be investigated on an industrial scale and further explored for a continuous operation mode.
Extractive fermentation for process integration of protease production by Aspergillus tamarii Kita UCP1279 and purification by PEG-Citrate Aqueous Two-Phase System
Published in Preparative Biochemistry & Biotechnology, 2022
Raniele Oliveira Alves, Rodrigo Lira de Oliveira, Osmar Soares da Silva, Ana Lúcia Figueiredo Porto, Camila Souza Porto, Tatiana Souza Porto
Among the extraction and purification methods, the Aqueous Two-Phase System (ATPS) is an interesting alternative. ATPS consists is a liquid-liquid separation technique, based on the simple phenomenon of immiscibility of two aqueous solutions, such as polymer-polymer (e.g, polyethylene glycol PEG and dextran) and polymer salt (e.g., phosphate, citrate, sulfate).[7,8] In addition to conventional polymers and salts, several other components of aqueous systems include smart polymers, polypropylene glycol (PPG), polyethylene oxide sulfide (PEOS), alcohols, organic acids, surfactants, as well as ionic liquids. Aqueous two-phase separation techniques allow the system to be integration with other variants, such as the aqueous two-phase flotation (ATPF) where the mass transfer mode is by solvent sublation, extractive fermentation supports the rapid exclusion of the product in a separate phase, bypassing the inhibition and degradation of the product in a bioprocess.[5,6,9,10]
Injectable hydroxypropyl chitin hydrogels embedded with carboxymethyl chitin microspheres prepared via a solvent-free process for drug delivery
Published in Journal of Biomaterials Science, Polymer Edition, 2021
Jieyu Zheng, Siyao Lv, Yalan Zhong, Xulin Jiang
Biopolymer microspheres have played a special and key role in many important fields due to their special size and structure and they have been widely investigated in drug delivery [20, 21]. The methods used in the preparation of biopolymer microspheres include emulsification [22], electrostatic droplet [23], spray drying [24], and solvent volatilization [25], etc. Among these methods, water-in-oil (W/O) emulsion technology has been widely used because of its simple preparation steps and mild processing conditions [26]. However, microspheres prepared by W/O emulsion method often have organic reagents and surfactant residues, which is not beneficial to biological safety. To address this concern, a novel method based on aqueous two-phase system was invented and applied to prepare microspheres [27–29]. Two different water-soluble polymer aqueous solutions are mixed and the system will be divided into two immiscible phases to form an aqueous two-phase system when the two appropriate polymer systems are chosen [30]. The aqueous two-phase method does not need to use organic solvents and surfactants, so the microspheres obtained after stir and solidification by this method are more environmentally friendly and suitable for biomedical field.