Unlocking Stability: The Crucial Role of Thermal Analysis in Lyophilization Temperature Optimization

Julienne Regele | Calliste Scholl
May 27, 2024

The method of drug delivery significantly influences the final stages of the manufacturing process. Currently, lyophilization—a widely adopted technique—enables drug developers to stabilize formulations and therapeutic molecules using a validated commercial approach. In this process, precise control of pressure and temperature within a lyophilizer facilitates the removal of liquids from formulations containing thermally sensitive or hydrolytically unstable active pharmaceutical ingredients or formulation components.1 The resulting solid product exhibits enhanced stability, an extended storage life, suitability for higher-temperature storage, and ease of packaging compared to aqueous solutions. Remarkably, over 60% of biologics available in today’s market owe their existence to lyophilization, rendering this technique exceptionally attractive for integration into the manufacturing process.

Syringe and needle with glass medical ampoule vials for injection. Medicine is dry white drug penicillin powder or liquid with of aqueous solution in ampulla

Stages of Lyophilization

Currently, many lyophilization strategies can be used to develop high-concentration monoclonal antibodies. To begin, the development of successful antibody therapies requires administration at high dose levels. However, it is challenging for high-concentration monoclonal antibodies to be delivered effectively due to their limited intrinsic stability. By introducing an optimal lyophilization process, developers would be able to increase stability, limit storage requirements, and ease the shipping issues. There are three distinct stages in the lyophilization process: freezing, primary drying, and secondary drying. The first stage, freezing, is carried out at temperatures below Tg (glass transition temperature) for an amorphous, or below Teu (eutectic temperature) for a crystalline state, for a sufficient period to allow for full transformation into a solid.2 To achieve high crystallization rate and complete crystallization, the annealing temperature is usually held between the Tg of the amorphous phase and the Teu of the bulking agent.2 Additionally, it is important to start off by using a moderate cooling point to prevent any degradation.

The subsequent phase, known as primary drying, eliminates frozen water by raising the shelf temperature and reducing chamber pressure. Optimizing primary drying can significantly reduce cycle time and depends on factors such as formulation, shelf temperature, container type, and chamber pressure.2 Overall, achieving a high sublimation rate with uniform heat transfer is the goal during this step. Following primary drying, we encounter the secondary drying phase. Here, water is extracted from the solute phase through desorption. The effectiveness of secondary drying hinges on the ramp rate, which varies based on the product type (whether amorphous or crystalline).2 Additionally, various stability-affecting factors—such as antibody concentration, excipients, and container properties—should prompt a case-by-case approach to secondary drying for optimal efficiency. A comprehensive grasp of these three pivotal stages contributes to successful lyophilized product development and streamlines the manufacturing process in drug development.

Utilizing Thermal Analysis to Prepare Lyophilized Solutions

While lyophilization offers advantages such as increased stability, solid-state drug delivery, and other benefits, it remains a highly specific process demanding meticulous control. Deviations from proper procedures can result in inadequate freezing, equipment overload, or sample damage, ultimately compromising drug efficacy and potency.3 Therefore, comprehensive characterization is essential to optimize sample preparation, lyophilization, and product delivery. Researchers must conduct thermal analysis throughout the entire process to assess how temperature variations impact material properties.

The Tg is the point at which there is increased mobility of a lyophilized sample as it transitions from its frozen, brittle state to a more viscous state.3 It is critical for researchers to identify the glass transition temperature to optimize the temperatures used at each step of the lyophilization process. TA Instruments offers, the Discovery DSC and the Multi-Sample X3 DSC to measure Tg directly. Both instruments utilize TA Instruments’ patented Fusion Cell design to provide the highest level of performance for the most accurate and robust thermal analysis measurements.3 The Multi-Sample X3 DSC offers a distinctive advantage: the capability to simultaneously run three samples, providing a wealth of data in a shorter timeframe.

After freeze drying a sample, researchers can use Thermogravimetric Analyzers (TGAs) to reliably detect even the smallest amount of residual moisture. This analysis can be used to evaluate the quality of the lyophilization process, predict how stable a product is likely to remain, and determine optimal parameters for lyophilization.4 In addition, TGA can also measure weight loss due to thermal decomposition, which can reveal insights into how the properties of the product might have changed during lyophilization. TA Instruments offers a range of TGAs for every lab’s needs. The TGA 55 is a rugged, reliable, and cost-effective option with proprietary Tru-Mass balance for the most accurate measurements across competitive models. The TGA 550 offers enhanced performance and flexibility with add-on features and optional expansion. Lastly, the TGA 5500 provides ultimate performance with less drift than any competitive TGA, plus the fastest heating and cooling rates available. Therefore, for any lab attempting to optimize their lyophilization process, TA Instruments offers a TGA to suit their needs.

Finally, it is important to make sure the in-solution properties of the protein have remained unchanged after lyophilization and reconstitution. The Nano DSC allows one to evaluate any alterations in the product’s stability or efficacy by measuring shifts in melting temperature and enthalpy. Using these parameters, the Nano DSC provides insights into whether the lyophilization process impacted molecular stability.

In the world of biologics, stability is crucial. Lyophilization, our trusted ally, preserves delicate formulations and therapeutic molecules. Yet, success hinges on precise temperature control. In this blog, we’ve highlighted the pivotal role of thermal analysis &ndash a compass guiding us toward optimal lyophilization conditions. By using this tool, we optimize the process and protect protein integrity during lyophilization.


  1. DiFranco, N. (2019, October 8). Lyophilization of Pharmaceuticals: An Overview. LLS Health CDMO. https://lubrizolcdmo.com/blog/lyophilization-of-pharmaceuticals-an-overview/
  2. 2Friday, January 1, & 2010. (n.d.). Lyophilization Strategies for Development of a High-Concentration Monoclonal Antibody Formulation: Benefits and Pitfalls. Retrieved November 24, 2023, from https://www.americanpharmaceuticalreview.com/Featured-Articles/117600-Lyophilization-Strategies-for-Development-of-a-High-Concentration-Monoclonal-Antibody-Formulation-Benefits-and-Pitfalls/
  3. How To Optimize Lyophilization with Thermal Analysis—TA Instruments. (n.d.). Retrieved November 24, 2023, from https://www.tainstruments.com/how-to-optimize-lyophilization-with-thermal-analysis/
  4. Wahl, V., Khinast, J., & Paudel, A. (2016). Lyophilized protein powders: A review of analytical tools for root cause analysis of lot-to-lot variability. TrAC Trends in Analytical Chemistry, 82, 468–491. https://doi.org/10.1016/j.trac.2016.05.012