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The 3.9 106 cells/mL seeding density also managed high viability (98%) on day 6 (Number 5C), which is desirable for transfer to the production step. probe to instantly adjust the perfusion rate based on real-time VCD measurements. The capacitance measurements correlated linearly with the offline VCD whatsoever cell densities tested (i.e., up to 130 106 cells/mL). Online control of the perfusion rate via the cell-specific perfusion rate (CSPR) decreased press usage by approximately 25% when compared with a platform volume-specific perfusion rate approach and did not lead to any detrimental effects on cell growth. This PAT tool was applied to six mAbs, and a platform CSPR of 0.04 nL/cell/day time was selected, which enabled rapid growth and maintenance of high viabilities for four of six cell lines. In addition, small-scale capacitance data were used in the scaling-up of N-1 perfusion processes in the pilot flower and in the GMP developing suite. Implementing a platform approach based on capacitance measurements to control perfusion rates led to efficient process development of perfusion N-1 for assisting high-density CHO cell ethnicities for the fed-batch process intensification. strong class=”kwd-title” Keywords: perfusion N-1, process intensification, capacitance, process analytical systems (PAT), cell-specific perfusion rate (CSPR), platform, scale-up, in-line probe, monoclonal antibody (mAb), Chinese hamster ovary (CHO) 1. Intro Despite much interest from your biopharmaceutical market in continuous upstream manufacturing processes, fed-batch processes remain the standard mode of production for stable proteins such as monoclonal antibodies (mAbs). A conventional fed-batch process is usually inoculated with an initial viable cell denseness (VCD) of 1 106 cells/mL. The volumetric productivity and developing throughput of a fed-batch process can be improved by inoculating the production bioreactor at a higher initial VCD (e.g., 2C8 106 cells/mL), therefore shortening the initial growth phase and total tradition period [1,2,3,4]. Furthermore, an even higher initial VCD (e.g., 10C20 106 cells/mL) can double fed-batch cell tradition titers [5,6], which are comparable to the high end of the best titers reported in the current literature [7]. Inoculation of the Eicosatetraynoic acid production bioreactor at a higher initial VCD requires the N-1 to accomplish a higher final VCD (e.g., 14C30 106 cells/mL), which can be accomplished through intensification of the N-1 with non-perfusion [8] or perfusion Eicosatetraynoic acid strategies [1,2]. However, only perfusion N-1 offers shown the feasibility of achieving final VCDs of greater than 60 to 100 106 cells/mL [9], enabling inoculation VCDs in the production bioreactor of greater than 10 106 viable cells/mL [5,6]. Because the fed-batch process intensification can achieve a great titer improvement or shortened tradition period by N-1 perfusion while remaining cost effective compared to traditional fed batch (overall press USD/g mAb) [10], the N-1 perfusion strategy has been widely used for mAb production in the cell tradition market [11,12]. One common method of controlling perfusion rate is definitely to perfuse a fixed volume that changes at a pre-defined rate with time, typically normalized to the working volume of the bioreactor and reported in vessel quantities per Eicosatetraynoic acid day (VVD). While this volume-specific exchange rate strategy is definitely relatively straightforward in implementation, this strategy tends to perfuse more press than the cells require to keep up in a healthy state to avoid the alternative condition where the perfused volume is too low, leaving the cells deficient in required nutrients [12]. The perfusion of extra media is problematic Rabbit Polyclonal to EPHB6 during scale-up of perfusion processes, where preparation and storage of large press quantities is challenging and is often limited by the size of the equipment in the manufacturing facility [13]. An elegant answer to this problem is definitely to perfuse on a cell-specific basis rather than a volume-specific basis [14]. The cell-specific perfusion rate (CSPR) describes the required amount of new media supplied to the culture on a per-cell basis and the equivalent amount of spent press perfused out through the cell retention device [15]. A perfusion strategy based on the.