blog  •  Aug 30

Importance of Purity Profiles in Metal Salts

Bioprocessing has become a vital method when manufacturing pharmaceuticals. After the development of recombinant DNA technology made large-scale production of therapeutic proteins possible, the need for various nutrients to support cell growth and productivity became apparent. Organic sources such as carbon and nitrogen are obvious necessities, but so too are a range of vitamins, minerals, and trace metals. Metal salts, such as calcium chloride, magnesium sulfate, and ferric nitrate, are just a handful of the many nutrients regularly added to the upstream processing of cell culture media formulations to optimize cell growth, deliver higher downstream titers, and to ultimately create a more robust bioprocess.

The critical role of metal salts in bioprocessing stems from their diverse and essential functions in cellular growth, metabolism, and API formation. Various metal ions are known to act as enzyme cofactors For example, magnesium is essential for many ATP-utilizing enzymes. Others, like calcium, play a significant role in cell signaling, membrane potential, and enzyme activation.

However, bulk or off-the-shelf metal nutrient solutions have been reported to increase the occurrence of cell culture failure due to lot-to-lot and vendor-to-vendor variability in quality, purity, and trace element profiles. Working with a trusted partner with over sixty years of experience in the development and synthesis of custom-tailored, high-purity metal nutrients might be the solution to your bioprocessing woes. Ascensus Specialties exceeds the FDA’s stringent cGMP regulations and its experts are well-versed in the latest process analysis technologies to ensure consistent metal salt purity and our scientists are some of the industry’s most knowledgeable experts.

The Importance of Determining Metal Salt Purity

While the definition of high- purity can differ from application to application, biopharma experts tend to define it as 99.99% or greater. Additionally, trace impurities need to be contained to ppm, ppb, or even lower concentrations. The purity of a metal salt takes multiple steps to quantify and verify when working at scale. These include techniques such as:

  • Spectroscopy (ICP-MS, AAS): Inductively Coupled Plasma Mass Spectrometry (ICP-MS) and Atomic Absorption Spectroscopy (AAS) can be used to determine the presence and concentration of various elements in the samples.
  • Chromatography: High performance liquid chromatography (HPLC) can separate individual components in a mixture and allow for detection of impurities.

Through our expertise and state-of-the-art facilities, Ascensus Specialties can create custom tailored metal salts for a customer’s specific needs. Metal salts manufactured by Ascensus undergo strict analysis and testing, so customers can expect to receive a bespoke product with a consistent purity profile something that bulk manufactures cannot guarantee.

Monoclonal antibodies (mAbs) serve as a prime example of why purity should not be compromised at any stage of a bioprocess. Since the 1980’s, mAbs-based therapies have become the primary option for many medical conditions. Chinese hamster ovary cells (CHO) and their derivatives have been embraced by the industry due to their adaptability to engineering, as well as their high efficiency and resilience in cell culture. These traits make them ideal hosts for producing recombinant protein therapies. As the demand for mAbs continues to grow, the main research focus is on improving cell culture performance and, in turn, optimizing the production of therapeutic proteins. Optimal mAb productivity and quality in CHO cell culture depends on many factors, including lactate consumption, energy metabolism, mAbs productivity and reagent quality.

The traditional approach of loading metal nutrients to a bioprocess stream via a 5-10% fetal bovine serum (FBS) solution has numerous setbacks, including lot-to-lot variability and an increased risk of microbial or viral contamination. Chemically-defined media (CDM) were developed to contain pre-set concentrations of trace metals and nutrients. Despite offering better protection from variability, achieving precise control of trace metal content and comprehensive media characterization in CDM remains challenging.

Negative Results of Inconsistent Purity and Lot-to-Lot Variability

Using metal nutrients with inconsistent purity profiles can lead to a range of significant negative effects on your cell culture. In industrial and chemical processes, these can translate into inconsistent product quality, lower yields, or outright failure of the cell culture – all costly and undesirable outcomes. Furthermore, the formation of unwanted byproducts can have catastrophic consequences downstream. The role of trace element in cell culture media and upstream processing is an emerging focus that could address several of these challenges.

Even minimal variations at ppb levels of certain elemental impurities can impact glycosylation patterns. This can lead to reduced target cell growth and even make growth cease or impact any therapeutic attributes.

Altered protein expression is another potential negative outcome of using impure or variable metal salts. The result is a lower quality, less efficacious product downstream. Dr. Nandu Deorkar, a leader in biopharma research and development, observed: “Trace elements in cell culture media and supplements may promote or inhibit cell growth and protein expression or quality to different levels during upstream processes.”

Overall, the concentration of trace metal ions in clinical or commercial cell culture medium can vary significantly across different vendors; even between different lots from a single source. While each vendor predetermines the optimal trace metal composition for their culture media, considerable discrepancy in these predefined values can be observed from one vendor to another. Moreover, most biologics platforms require a custom solution to reach their optimal performance. Therein lies the importance of partnering with a manufacturer that is capable of offering consistent high-purity metal nutrients.

The Ascensus Advantage

As a trusted partner for custom-tailored solutions for over 60 years, Ascensus’ state-of-the-art manufacturing facilities across the United States and in the U.K., has allowed us to become a trusted supplier, contract developer and manufacturing service in the biopharma industry.

As an FDA registered manufacturing facility, Ascensus operations exceed the rigorous cGMP (current Good Manufacturing Practices) requirements. With dedicated rooms and equipment, production suites and Verified line clearance, all but eliminates contamination risk from bioburden that can build up during salt production. Ensuring our partners have the highest purity metal salts for their needs.

Metal Salt Purity is a key to effective bioprocessing

Case Study Example: Ferric Ammonium Citrate

Having a trusted partner by your side throughout your project’s critical development stages is vital for any clinical campaign. A recent collaboration with a top-tier pharmaceutical innovator highlights the importance of trace metal profiles in clinical and commercial bioprocesses. Our client was facing considerable headwinds sourcing high-purity GMP ferric ammonium citrate (FAC) for one of their mAb production platforms. They sought to synthesize ferric ammonium citrate, which is used by cells to manufacture monoclonal antibodies.

The client approached Ascensus with a major issue. Trace metals were causing their bioprocesses to shut down, due to unacceptable levels of impurities. Despite “scavenging” and a multitude of other traditional purification methods employed by the client, they were unable to get concentrations down to acceptable levels of trace impurities. As such, the client tasked Ascensus Specialties with engineering the undesired trace metal impurities out of the finished product.

Over the course of an 18-month campaign, Ascensus Specialties developed a bespoke GMP product which exceeded the client’s target purity specification. This allowed the customer to run their clinical-stage bioprocess with excellent reliability and reproducibility. Production of the material in an ISO Class 7 GMP facility, resulted in increased process control and bioburden management.

Metal Salt Purity: The Key to Effective Bioprocessing

The purity of metal salts used in bioprocessing is as important as the elements that comprise the compound. What may seem like a miniscule change in purity can lead to lost production and research in an instant.

If you're in need of metal salts, you can view the full range of the Ascensus product line or reach out to the team to discuss your goals and find a solution.

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