Scale-down of the inactivated polio vaccine production process

The anticipated increase in the demand for inactivated polio vaccines resulting from the success in the polio eradication program requires an increase in production capacity and cost price reduction of the current inactivated polio vaccine production processes. Improvement of existing production processes is necessary as the initial process development has been done decades ago. An up-to-date lab-scale version encompassing the legacy inactivated polio vaccine production process was set-up. This lab-scale version should be representative of the large scale, meaning a scale-down model, to allow experiments for process optimization that can be readily applied. Initially the separate unit operations were scaled-down at setpoint. Subsequently, the unit operations were applied successively in a comparative manner to large-scale manufacturing. This allows the assessment of the effects of changes in one unit operation to the consecutive units at small-scale. Challenges in translating large-scale operations to lab-scale are discussed, and the concessions that needed to be made are described. The current scale-down model for cell and virus culture (2.3-L) presents a feasible model with its production scale counterpart (750-L) when operated at setpoint. Also, the current scale-down models for the DSP unit operations clarification, concentration, size exclusion chromatography, ion exchange chromatography, and inactivation are in agreement with the manufacturing scale. The small-scale units can be used separately, as well as sequentially, to study variations and critical product quality attributes in the production process. Finally, it is shown that the scale-down unit operations can be used consecutively to prepare trivalent vaccine at lab-scale with comparable characteristics to the product produced at manufacturing scale.