Komuczki D, Hesse N, Schmidt J, Satzer P. A step closer to continuous buffer preparation from solids: Predicting powder compaction and how to prevent it.
N Biotechnol 2023;
76:98-105. [PMID:
37230177 DOI:
10.1016/j.nbt.2023.05.003]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Revised: 05/13/2023] [Accepted: 05/18/2023] [Indexed: 05/27/2023]
Abstract
The preparation of buffer solutions used in the biopharmaceutical industry is typically performed manually by the addition of one or multiple buffering reagents to water. Recently, the adaptation of powder feeders for continuous solid feeding was demonstrated for continuous buffer preparation. However, the intrinsic characteristics of powders can change the stability of the process, due to the hygroscopic nature of some substances and humidity induced caking and compaction behavior, but there is no simple and easy methodology available predicting this behavior for buffer species. To predict which buffering reagents are suitable without special precautions and investigate their behavior, force displacement measurements were conducted with a customized rheometer over 18hours. While most of the eight investigated buffering reagents indicated uniform compaction, especially sodium acetate and dipotassium hydrogen phosphate (K2HPO4) showed a significant increase in yield stress after 2hours. Experiments conducted with a 3D printed miniaturized screw conveyor confirmed the increased yield stress measurement by visible compaction and failure of the feeding. By taking additional precautions and adjusting the design of the hopper, we demonstrated a highly linear profile of all buffering reagents over a duration of 12 and 24hours. We showed that force displacement measurements accurately predict the behavior of buffer components in continuous feeding devices for continuous buffer preparation and are a valuable tool to identify buffer components that need special precautions. Stable, precise feeding of all tested buffer components was demonstrated, showing the importance of identifying buffers that need a specialized setup with a fast methodology.
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