The baculovirus expression vector system (BEVS) has emerged as a powerful tool for the production of recombinant proteins used as therapeutics, reagents, and diagnostics. In order to maximize the system’s efficiency and thereby reduce costs, optimizing production parameters is imperative. A critical factor in optimization is the production of a high-quality baculovirus stock with a high-titer, pure clonal population of recombinant virus that is stable over time. Baculovirus stocks may contain alternate varieties of infectious virus due to cross-contamination, outgrowth of non-recombinant virus, and excision of inserts attributable to some recombinant virus production technologies. Since the advent of the BEVS, the “gold standard” for production of pure baculovirus stocks has been plaque purification. Briefly, plaque purification involves infecting a monolayer of cells with dilutions of virus before applying an agarose overlay to the monolayer. After a 5–7 day incubation, isolated plaques can be picked, virus eluted from the agarose plug, and amplified. The drawbacks of plaque purification are: (1) it is time and labor-intensive; (2) the results hinge greatly on the health of the cells and the cell density at infection; (3) identification and picking of isolated plaques is challenging; and (4) the integrity of the procedure is easily compromised by virus diffusion and mass flow of virus-containing liquid beneath the agarose overlay…
Category: <span>Biologics Production</span>
The impact of individual and interactive behaviors of various fermentation process parameters on laccase and peroxidase-free tyrosinase production were investigated by isolated Streptomyces antibioticus RSP-T1. Six key bioprocess factors (medium pH, rpm, incubation time, sodium chloride concentration, complex nitrogen [yeast extract + peptone], and carbon source [maltose]) were selected based on using a one variable at a time methodology. All selected parameters had an impact at individual and interactive levels on tyrosinase production. Only 25% of the improved tyrosinase production was attributed to the optimized fermentation parameters selected. Regarding the nutritional parameters, the complex nitrogen/carbon source concentration (maltose and yeast extract + peptone) was found to have the most significance impact on overall tyrosinase enzyme production. Physiological growth factors (pH, rpm, and incubation time) played key roles at an interactive level. A maximum yield of 12.60 IU/mL tyrosinase production was achieved with optimized medium, adjusted to 7.5 pH, consisting of 0.75% maltose (w/v), 0.2% yeast extract (w/v), 0.2% peptone (w/v), and 1.25% sodium chloride (w/v) at 160 rpm in 24 hours. This study identified the optimum medium component concentrations for improved tyrosinase production by S. antibioticus RSP-T1. This strain requires complex nitrogen sources (yeast extract and peptone) for increased product yield. Overall, a greater than 250% increase in tyrosinase production was achieved using this optimization approach, as compared to conventional methods…
Viral clearance studies are required for pharmaceuticals derived from human and/or animal sources such as recombinant proteins produced in eukaryotic cell lines, human blood products and vaccines, and even for some critical class III medical devices. It is mandatory to demonstrate that steps in the manufacturing process are capable of inactivating or removing potential viral contaminants. For this, a laboratory-scale (downscale) of the process step is developed and challenged with different model virus solutions. The viral concentrations are quantitatively determined in the feed material and the relevant product fraction. The ratio of both defines the reduction in virus and specifies the viral inactivation or viral removal capacity of the investigated process step…
Biosimilars, and related biopharmaceutical biobetters and biogenerics, are still relatively new, but are already starting to impact worldwide biopharmaceutical markets. Most discussions of biosimilars center on developed regions where markets are mature and manufacturing capabilities allow for the cost-efficient manufacture of these complex molecules. This article covers the development of these products outside the United States (US), European Union (EU), and other developed, generally rather affluent and high-technology economy-based countries. To start, we first offer some definitions…
The expansion of stem cells, including mesenchymal stem cells (MSCs), has been successfully demonstrated using microcarrier-based small bioreactors such as spinner flasks. In this study, we explored a simple alternative for microcarrier-based MSC expansion using conventional shake flasks. This method relies on a new type of shaker with built-in CO2 gas control capability, the New Brunswick™ S41i incubator shaker. The expansion of adipose-derived mesenchymal stem cells (AdMSCs) was compared between shake and spinner flasks containing microcarriers. The AdMSCs were seeded at a density of 3 × 103 cells/cm2 in both setups, each containing 0.5 g of plastic microcarriers and 50 mL of stem cell growth medium. The cell culture experiments were conducted over 12 days with samples collected daily for cell growth, biochemistry, and metabolite analysis. The study revealed that AdMSCs cultured under shake flask conditions achieved excellent growth under 12-day batch-culture conditions. Finally, the AdMSCs expanded using the shake flask method retained high quality stem cell characteristics, as indicated by CD44 and CD90 stem cell marker assays, and the ability of these cells to differentiate into either adipocytes or osteocytes…
This paper places the “Quality by Design” (QbD) in an overall context and provides the following straightforward definition so that QbD can be effectively used to solve a wide variety of important problems:
Quality by Design–During the design stage, to achieve a well-defined goal, iteratively apply science and engineering methods to anticipate, identify, understand, resolve, and control problems that will be encountered during testing, operating, and verifying the goal over its lifecycle.
The viewpoint of the paper is to view QbD as “Success by Design.” The definition is based on answering the following question: What will be required to provide assurance that the enabler developed during the design stage will successfully reach the goal over the entire lifecycle before leaving the design stage? The paper argues that QbD should not be implemented as a program, but used as a tool. To provide understanding, the paper explores underlying concepts, the history of QbD, develops a working definition, and then applies it to biopharmaceutical development and manufacturing…
