Analysis of the Shear Stresses in a Filling Line of Parenteral Products: The Role of Tubing

Parenteral products appear to be sensitive to process conditions in bioprocessing steps, such as interfacial stress and shear stress. The combination of these elements is widely believed and proven to influence product stability, but the defined roles of these players in the product damage process have not yet been identified. The present work addresses a current industrial problem, by focusing on the analysis of shear stress on protein-based therapeutics flowing in tubing by means of Computational Fluid Dynamics simulations. The purpose of this article is not to pinpoint the mechanism triggering the damage of the product, but it represents the first step towards wider experimental investigations and introduces a new strategy to quantify the average shear stress. The field of scale-down approaches, used to scale the commercial process down to the laboratory level, is also explored. Since quality control is critical in the pharmaceutical realm, it is essential that the scale-down approach preserves the same stress exposure as the commercial scale, which in the present work is considered to be that resulting from shear effects. Therefore, a new approach for scaling down the commercial process is proposed, which has been compared with traditional approaches and shown to provide greater representativeness between the two scales.

In-vial printing and drying of biologics as a personalizable approach

This study addressed the need for a flexible (personalizable) production of biologics, allowing their stabilization in the solid state and processing of small batch volumes. Therefore, inkjet printing into vials followed by a gentle vacuum drying step at ambient temperature was investigated by screening different formulations with a 2²-full factorial design of experiments regarding printability. Human Serum Albumin (HSA) was used as a model protein in a wide range of concentrations (5 to 50 mg/ml), with (10 w/v%) and without the surfactant polysorbate 80 (PS80). PS80 was identified to positively affect the formulations by increasing the Ohnesorge number and stabilizing the printing process. The dispensed volumes with a target dose of 0.5 mg HSA were dried and analyzed concerning their residual moisture (RM) and protein aggregation. All investigated formulations showed an RM < 10 wt% and no significant induced protein aggregation as confirmed by Size Exclusion Chromatography (<2.5%) and Dynamic Light Scattering (Aggregation Index ≤ 2.5). Additionally, long-term printability and the available final dose after reconstitution were investigated for two optimized formulations. A promising formulation providing ∼93% of the targeted dose and a reconstitution time of 30 s was identified.

2D and 3D inkjet printing of biopharmaceuticals - A review of trends and future perspectives in research and manufacturing

There is an ongoing global shift in pharmaceutical business models from small molecule drugs to biologics. This increase in complexity is in response to advancements in our diagnoses and understanding of diseases. With the more targeted approach coupled with its inherently more costly development and manufacturing, 2D and 3D printing are being explored as suitable techniques to deliver more personalised and affordable routes to drug discovery and manufacturing. In this review, we explore first the business context underlying this shift to biopharmaceuticals and provide an update on the latest work exploring discovery and pharmaceutics. We then draw on multiple disciplines to help reveal the shared challenges facing researchers and firms aiming to develop biopharmaceuticals, specifically when using the most commonly explored manufacturing routes of drop-on-demand inkjet printing and pneumatic extrusion. This includes separating out how to consider mechanical and chemical influences during manufacturing, the role of the chosen hardware and the challenges of aqueous formulation based on similar challenges being faced by the printing industry. Together, this provides a review of existing work and guidance for researchers and industry to help with the de-risking and rapid development of future biopharmaceutical products.

The use of a surface active agent in the protection of a fusion protein during bioprocessing

The bioprocessing of a fusion protein is characterised by low yields and at a series of recovery and purification stages that leads to an overall 90% loss. Much of this apparent loss is due to the denaturation of a protein, missing a vital affinity ligand. However, there is evidence of the protection of degradation products which occurs in the presence of shear plus air/liquid interfaces. This study seeks out to characterise the loss and use ultra‐scale‐down studies to predict its occurrence and hence shows these may be diminished by the use of protective reagents such as Pluronic F68.

Synthesis of isomaltooligosaccharides and oligodextrans in a recycle membrane bioreactor by the combined use of dextransucrase and dextranase

A recycle ultrafiltration membrane reactor was used to develop a continuous synthesis process for the production of isomaltooligosaccharides (IMO) from sucrose, using the enzymes dextransucrase and dextranase. A variety of membranes were tested and the parameters affecting reactor stability, productivity, and product molecular weight distribution were investigated. Enzyme inactivation in the reactor was reduced with the use of a non-ionic surfactant but its use had severe adverse effects on the membrane pore size and porosity. During continuous isomaltooligosaccharide synthesis, dextransucrase inactivation was shown to occur as a result of the dextranase activity and it was dependent mainly on the substrate availability in the reactor and the hydrolytic activity of dextranase. Substrate and dextranase concentrations (50-200 mg/mL(-1) and 10-30 U/mL(-1), respectively) affected permeate fluxes, reactor productivity, and product average molecular weight. The oligodextrans and isomaltooligosaccharides formed had molecular weights lower than in batch synthesis reactions but they largely consisted of oligosaccharides with a degree of polymerization (DP) greater than 5, depending on the synthesis conditions. No significant rejection of the sugars formed was shown by the membranes and permeate flux was dependent on tangential flow velocity.

Effect of high shear rate on stability of proteins: kinetic study

Size-exclusion chromatography (SEC) was used to monitor the time-course of protein degradation induced by high shear rates during the formulation and manufacture of controlled-release pharmaceutical dosage forms. SEC with multi-angle laser light-scattering (MALLS) detection was used to characterize the aggregation products, determining their absolute molecular weight. A stability-indicating method was developed and validated to obtain reliable drug degradation data. The results obtained according to the ICH guidelines confirm that the system and methods proposed are suitable for their intended use. The degradation kinetics are influenced by the type of protein and the effect of the shear rate on their stability. Reversible pseudo-first order degradation kinetics were observed for bovine beta-lactoglobulin, whereas for human (HSA) and bovine serum albumin (BSA), a monomer-dimer transition was observed, independently of the rate of shear. However, trimer formation was also observed for HSA, especially at high shear rates. The kinetic model may thus be described as a two-step process: a monomer-dimer, and dimer-trimer transition.

Effect of operating variables on the yield of recombinant trypsinogen for a pulse-fed dilution-refolding reactor

The inclusion body process route for manufacturing proteins offers distinct process advantages in terms of expression levels and the ease of initial inclusion body recovery. The efficiency of the refolding unit operation, however, does determine the overall economic feasibility of a process. Dilution refolding is the simplest and most extensively used refolding operation, although significant yield losses often occur due mainly to aggregation. Operating variables may have a significant effect on the degree of aggregation, but a systematic study has not been reported. This study investigates the effect of operating variables on the dilution refolding of solubilized r-trypsinogen inclusion bodies in a pulse-fed stirred reactor. Variables investigated were inclusion body washing, stirring speed, feed rate, concentration of solubilized r-trypsinogen, and concentration of urea during solubilization of the inclusion bodies. Additionally, the effect of baffles in the reactor was investigated. The yield of renatured r-trypsinogen varied between 12 +/- 0.2% and 21 +/- 1.0% depending on the specific combination of operating variables employed. It is clear that a suboptimal operating strategy can significantly reduce protein yield. In particular, we note that an increased intensity of mixing adversely affected yield in contrast to previous reports indicating that enhanced dispersion increases yield. We conclude that yield is determined not only by the efficiency of dispersion, but also by the local chemical environment of the protein as it folds, and the rate of change of this environment. This will be controlled by micromixing effects, and hence the intensity of agitation, in a complex manner requiring further characterization.