ABSTRACT
The production of biologicals is subject to strict governmental regulations. These are drawn up in current good manufacturing practices (cGMP), a.o. by the U.S. Food and Drug Administration. To implement cGMP in a production facility, plant automation becomes an essential tool. For this purpose Manufacturing Execution Systems (MES) have been developed that control all operations inside a production facility. The introduction of these recipe-driven control systems that follow ISA S88 standards for batch processes has made it possible to implement cGMP regulations in the control strategy of biological production processes. Next to this, an MES offers additional features such as stock management, planning and routing tools, process-dependent control, implementation of software sensors and predictive models, application of historical data and on-line statistical techniques for trend analysis and detection of instrumentation failures. This paper focuses on the development of new production strategies in which cGMP guidelines are an essential part.
ABSTRACT
A software sensor was developed to determine the volumetric biomass activity of animal cell cultivations on-line. It was based on the on-line estimation of the ATP-production rate from the oxygen uptake and the lactic-acid production rate. The sensor was verified for a batch culture of Vero cells, and a batch and a continuous culture of hybridoma cells. For the hybridoma cells, the sensor showed a good correlation with the biomass concentration. However, this was not the case for the Vero cells. As soon as glutamine was exhausted, the biomass activity stabilized, whereas the amount of biomass almost doubled. Because the sensor developed responds to nutrient limitations much faster than becomes visible through cell density measurements, and because the volumetric biomass activity can be related to the volumetric consumption rates and production rates of important metabolites, it shows excellent possibilities for control purposes.
ABSTRACT
The Batch Control System for Vaccines (BCSV), a new Man Machine Interface (MMI) for the control of cultivations in bioreactors, was developed according to SP-88. SP-88 is the ISA standard for Batch Control Systems. Among others, SP-88 supplied the concept of recipes, which organize and specify the monitoring and control requirements for manufacturing. Process optimisation and compliance to GMP rules and regulations were the main objectives for this development.The most important features of the BCSV interface include: - implementation at production, pilot and R & D scale to assure easy transfer of knowledge and experience at the various stage of process development; - independency of underlying hardware to ensure similar "look and feel" for different pieces of equipment; - in-house development and maintenance of recipes to have maximum control over applications; - interactive communication between operator and BCSV during recipe execution. GMP compliance was assured not only by considering governing sets of GMP regulations, but also by taking up the interface in a overall Information & Automation strategy and by setting up a QA strategy for the entire life cycle of the system.
ABSTRACT
A static method was developed that simultaneously determined the solubility of oxygen and the oxygen-transfer coefficient in a stirred bioreactor. It was based on the static method developed by van Sonsbeek et al. to determine the ka in a liquid-impelled loop reactor. Only physical properties of the liquid were used to determine both parameters using a mass spectrometer. Data about the solubility of oxygen in water are available from the literature. Therefore, the solubility of oxygen in water was used to compare our data with published data. Furthermore, the solubility of oxygen in trypticase soy broth was compared to literature data. No significant deviations between our data and literature data could be observed. Our static method and the commonly applied dynamic method to determine the oxygen-transfer coefficient yielded similar results. The effect of temperature on the oxygen-transfer coefficient could be expressed as the activation energy needed for the transition of oxygen from the gas to the water phase. This was verified using the Arrhenius equation.
