Xcellerex XDUO Quad
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Characterization of Xcellerex™ XDM and XDUO 100 single-use mixers This application note describes mixing and heatingcooling characterization data for the Xcellerex XDM/ XDUO 100 single-use mixer. A design of experiments (DoE) approach to liquid-liquid mixing was successfully used to establish a statistical model to predict the mixing time throughout the working range. Liquidliquid mixing times as low as 13 s were observed at the nominal volume (100 L) and highest viscosity tested (20 cP). Further, mixing of two different solids, PBS and saline, was tested. Mixing to 95% homogeneity (tm95) of both solids was reached within 50 s. Heating of liquid from 5°C to 20°C and 20°C to 37°C was achieved within 1.4 h for all tested volumes (30, 65, and 100 L). Cooling from 37°C to 20°C and 20°C to 5°C was achieved within 1.5 h except cooling from 20°C to 5°C at 30 L, which took 2.0 h. Introduction Xcellerex single-use mixers (XDM and XDUO) are available in several different configurations. In terms of mixing capability, the XDM and XDUO are identical. XDUO, however, offers more powerful automation capabilities than XDM. The XDM mixers range in size from 50 to 1000 L, while XDUO mixers are available from 100 to 2500 L. In common for all configurations is the robust mixing performance and ease of use. The mixers are designed for process development, commercial and clinical production of biopharmaceuticals, vaccines, and other biologics. Xcellerex mixers support upstream and downstream applications for preparation of buffer, media, product and intermediates, as well as other process fluids. The aim of this study is to give a detailed description of the physical characteristics of XDM/XDUO 100 in terms of mixing and heating-cooling. The mixing properties of XDM/XDUO 100 were investigated regarding both liquids and different types of solids. For mixing of liquids, a DoE approach was applied where liquid volume, viscosity, and impeller speed were varied to create a statistical model predicting the mixing time across the working range. In addition to liquid mixing, mixing of solids was investigated by preparation of two model solutions; PBS and saline, to show the mixer’s ability to handle solids. Heating and cooling times for different temperature intervals were investigated for minimum, middle, and nominal liquid volumes (30, 65, and 100 L). The characterization data presented in this application note is essential for optimizing the mixing or heating-cooling protocol of XDM/XDUO 100 for bioprocess applications, and for effective scale-up. Materials and methods System setup The mixer was equipped with an XDM 100 Plus bag and an Xcellerex temperature probe. A temperature control unit (TCU) was used to control the temperature of the liquid (Polyscience, 3 kW). External pH (ProMinent), temperature, and conductivity probes (Ahlborn) were used for logging of data via a data logger (Ahlborn). Liquid-liquid mixing The liquid-liquid mixing time was assessed by adding pulses of acid and measuring the pH change at different positions in the mixer (Fig 1). The tests were performed according to DoE where impeller speed, volume, and viscosity were varied simultaneously. The factorial design was a central composite design. The mixer bag was filled with liquid to the volume to be tested (30, 65, and 100 L). For the tests at 1 cP viscosity, the liquid consisted of 0.1 M NaCl in purified water. For tests at 10 and 20 cP, sucrose and NaCl were dissolved in water to generate a viscous liquid with a final NaCl concentration of 0.1 M. The impeller was set to rotate in a counterclockwise (CCW) direction giving an upward pumping mixing pattern. The temperature was controlled at 20°C. For pH

(0.2 M HCl in purified water, 10 or 20 cP sucrose) was added at a ratio of 1:2667 for 1 cP and 1:1000 for 20 cP of the liquid volume in the mixer. The ratios were chosen to induce a pH step change of approximately 1 pH unit. The pH was recorded at nine positions in the mixer at 100 L (Fig 1). The probes were arranged to cover all areas where poor mixing could be expected to occur. The pH probes were connected to an external data logger for logging of data. The number of probes was reduced as the liquid volume was lowered. The mixing time was assessed by calculating the time to reach 95% of...

The tm95 varied between 8 and 25 s for the tested conditions (Fig 2). The mixing time decreased with decreasing volume and increasing impeller speed. Mixing was generally faster at the lower viscosities. The average difference in tm95 for the fastest and slowest probe position for each run was 6 s, indicating that mixing is fast and efficient throughout the whole mixer volume. The resulting tm95 from the slowest probe position were evaluated using the statistical software MODDE. A multiple linear regression (MLR) model was created from the central composite test design. The investigated...

Ordering information Product Product code Xcellerex XDM-T Jacketed Stainless Steel Mixing System Xcellerex XDUO-T Jacketed Stainless Steel Mixing system Fig 6. t95 results from the heating-cooling tests for different temperature ranges. The error bars display one standard deviation. Conclusions This characterization study demonstrates the ability of Xcellerex XDM/XDUO 100 single-use mixers in the preparation and handling of solutions in multiple applications and conditions. Robust liquid-liquid mixing times as low as 13 s were observed at the maximum volume and viscosity tested. The mixing...