Material Classification in Cell Therapy: Starting, Ancillary, Raw Materials & Excipients Explained

Cell therapy development relies on a complex and highly specialized supply chain. However, navigating the terminology used to classify biological materials—such as male AB serum, human serum albumin, or leukopaks—can be challenging.

This blog aims to demystify these classifications by providing clear definitions.

Starting Materials: Core Elements

Starting materials are the initial biological materials that are incorporated as significant structural fragments at the beginning of the manufacturing process to create a cell-based medicinal product.

Examples of starting materials:

• Vectors/Plasmids
• Cells: Leukopaks 

Ancillary vs. Raw Materials: A Matter of Location

When it comes to substances used during the manufacturing process that are not intended to be in the final product, you will encounter 2 similar terms: ancillary and raw materials.

Ancillary/Raw materials (AMs) are substances used during the manufacturing process that come into contact with cells or tissues but are not intended to be present in the final product.

The term AM (US) is not globally recognized by regulators and is commonly referred to as raw material in some jurisdictions, such as in Europe 

• Ancillary material (US): The term "ancillary material" is commonly used in the United States (e.g., USP and ISO^1,2). However, it is not a globally recognized regulatory term.
• Raw material (Europe): In Europe, the term "raw material" is more commonly used (e.g., EP³). It serves the same function as an ancillary material in the manufacturing process.

Examples of ancillary/raw materials:

• Growth factors
• Enzymes
• Human serum albumin 
• Male AB serum

Excipient: Formulation Essentials

An excipient is a substance other than the active pharmaceutical ingredient (API) that is included in the final formulation.

It plays a critical role in ensuring, for example, the stability, bioavailability, and delivery of the therapeutic product, and may also contribute to the physical characteristics of the formulation, such as viscosity, osmolarity, or pH — all of which are essential for maintaining cell viability and product performance in cell-based therapies.

Examples of excipients:

• Buffers
• Human serum albumin

Classifying the Materials

Based on these definitions, here’s how commonly used materials in cell therapy are typically classified based on their role in the process:

Tip: Ensure your dossiers reflect the terminology used by regulators, not internal company-specific language.

Download the PDF for a quick visual summary of these material classifications. 

Ensuring Quality and Safety from the Start

Success of a cell therapy depends on thorough supplier evaluation, comprehensive documentation, appropriate risk mitigation, and proactive planning for development phase transitions. As regulatory frameworks evolve, organizations must maintain flexibility while ensuring patient safety and product quality remain paramount in raw material selection decisions.

Grifols Bio Supplies offers high-quality biological materials tailored to meet the evolving needs of cell therapy developers—ensuring safety, compliance, and performance from the start.

• Contact Form: Send your query through our website at biosuppliesproducts.com/en/request-a-rep
• Email: Reach us directly at biosupplies_contactus@grifols.com.

Grifols: Your ally in cell therapy.