Tuesday, April 26, 2016

Cell Culture Media: Balancing Resources with Results

Why does medium matter?

It all starts with media. Without an appropriate growth medium, no biopharmaceutical process would exist. The proper medium allows for cells to grow and generate product. Going beyond the fact that cell culture processes would simply not exist without cell culture media, the medium (and associated feeds for fed-batch processes) represents a large portion of the cost of a biopharmaceutical process. Cell culture media are complex entities that encompass large quantities of raw materials as well as a high level of technical expertise, driving up the cost per litre.

What are the advantages of an optimized medium formulation compared to an off the shelf product? 

Many people will choose to start with standard off the shelf products for their cell culture processes. While there are a wide variety of products available on the market, there are several important reasons to consider using an optimized medium formulation instead. The first is to tailor a medium formulation specifically for your own cell line. Every cell line will respond differently to standard products, and optimizing a medium formulation is the best way to ensure that you use a medium that works best for your application and requirements. Additionally, as you generate different cell lines with varying genetic constructs for new products, your cells may begin to respond differently. Having an optimized medium formulation allows you to adapt to these changes while maintaining growth and productivity. Using a standard product also means you are bound to a single vendor with no access to proprietary formulations. With your own optimized medium, you have full access to the formulation, with the ability to manufacture it with a vendor of your choice.

What factors should I consider when developing an optimized medium?

As discussed previously, optimizing a medium formulation to get you the best growth and productivity is the main driving factor, and allows you to minimize the amount of medium used and therefore your overall COGS. It is important to also consider what the criteria are for your optimized medium. For many industries, having a fully chemically defined, non-animal origin medium is critical. This minimizes lot to lot variability and is highly desirable from a regulatory standpoint. Ease of use is also important to consider. This encompasses storage aspects, such as shelf life, and shipping and handling conditions. Ease of use also involves simplifying the process for the operator. As media and feeds become increasingly complex, how difficult does it become to formulate? Will operators have to perform risky pH adjustments with large volumes of corrosive reagents? Will high temperatures be needed to dissolve certain components, and can these high temperatures be achieved as the industry moves towards more single-use technologies? These and other factors must be considered when developing an optimized medium formulation.

What resources are required to develop an optimized medium?

The actual raw materials that form the bulk of a cell culture medium are generally inexpensive. The resources required for an optimized medium formulation that drive up the ultimate cost per liter are time, personnel, equipment, and expertise. With the increasing use of multivariate approaches (Design of Experiments, Principal Component Analysis), the use of high throughput systems become highly advantageous, reducing personnel requirements. Finally, expertise in media development is something that comes only with years of experience in the industry and cannot be bought with any amount of money.

So how do I develop an optimized medium formulation?

There are several approaches to media optimization. Some methods include titration, reverse engineering of other media, and metabolomics. While some of these methods are effective, when implemented on their own, they are time consuming, labor intensive, and heavily resource-dependent. A modern, DoE based approach to media development for CHO based processes is the CHOptimizer® Media Builder. CHOptimizer® consists of three distinct phases. The package is designed to be integrated into our ambr™15 system for automation and ease of use. In the first phase, four chemically defined, non-animal origin based media are blended in different ratios, according to a mixtures design DoE approach. Subsequent phases incorporate spent media analysis and fractional factorial DoE approaches to develop an optimized medium formulation, feed formulation, and corresponding feeding strategy. CHOptimizer® base media are developed using the expertise of Lonza Biologics, and combines a modern, high throughput approach with traditional ideas to deliver an optimized medium in a short timeline, with field based support. It also offers full access to the formulation for ultimate flexibility in the future.

To learn more about CHO media optimization join Sartorius Stedim Biotech’s workshop, chaired by Dr. Michael Gillmeister, Lonza at the IBC Cell Line Development & Engineering Conference, San Francisco, 13th June at 11.45am.

About the author:
Dr. Michael Gillmeister received his Ph.D. in Chemical and Biomolecular Engineering from the Johns Hopkins University in collaboration with the University of Maryland School of Medicine specializing in glycosylation, transient protein production, and neurobiology. In 2009, Mike joined the Gibco® research and development group and was responsible for next-generation media and sera projects. He then led media and process development projects to modulate product quality and maximize titer for PD-Direct® Custom Media Services using high-throughput and bioreactor technologies. Currently, Mike leads Protein Expression Media R&D and the CHOptimizer™ media optimization service for Lonza Walkersville.

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