Philippe Lam

Protein Aggregation in Frozen Trehalose Formulations: Effects of Composition, Cooling Rate, and Storage Temperature

This study was designed to assess the effects of cooling rate, storage temperature, and formulation composition on trehalose phase distribution and protein stability in frozen solutions. The data demonstrate that faster cooling rates (>100°C/min) result in trehalose crystallization and protein aggregation as determined by Fourier Transform Near-Infrared (FT-NIR) spectroscopy and size-exclusion chromatography, respectively. Conversely, at slower cooling rates (≤1°C/min), trehalose remains predominantly amorphous and there is no effect on protein stability. Evaluation of storage temperatures demonstrates that aggregation increases more rapidly at -14°C compared with higher (-8°C) and lower (-20°C) storage temperatures; however, a relatively higher amount of cumulative aggregation was observed at lower (-20°C) temperature compared with higher storage temperatures (-14°C and -8°C). Further evaluation of the effects of formulation composition suggests that the phase distribution of amorphous and crystallized trehalose dihydrate in frozen solutions depends on the ratio of trehalose to mAb. The results identify an optimal range of trehalose-mAb (w/w) ratio, 0.2-2.4, capable of physically stabilizing mAb formulations during long-term frozen storage-even for fast cooled (>100°C/min) formulations.

An Improved Method for Visualizing the Morphology of Lyophilized Product Cakes

Due to low optical contrast, the morphology of lyophilized product cakes is difficult to observe and photograph. Furthermore, internal structures are normally not visible unless the cake is fractured. Because most lyophilized substances are hygroscopic and quite fragile, the product cake, once removed from the vial, will rapidly degrade. We propose herein a technique that allows a lyophilized product cake to be preserved, manipulated, and easily observed outside the vial. This technique yields high-quality, cross sectional images that reveal intricate fine structures without the use of expensive specialized equipment.

Impact of Vial Capping on Residual Seal Force and Container Closure Integrity.

The vial capping process is a critical unit operation during drug product manufacturing, as it could possibly generate cosmetic defects or even affect container closure integrity. Yet there is significant variability in capping equipment and processes, and their relation to potential defects or container closure integrity has not been thoroughly studied. In this study we applied several methods—residual seal force tester, a self-developed system of a piezo force sensor measurement, and computed tomography—to characterize different container closure system combinations that had been sealed using different capping process parameter settings. Additionally, container closure integrity of these samples was measured using helium leakage (physical container closure integrity) and compared to characterization data. The different capping equipment settings lead to residual seal force values from 7 to 115 N. High residual seal force values were achieved with high capping pre-compression force and a short distance between the capping plate and plunge. The choice of container closure system influenced the obtained residual seal force values. The residual seal force tester and piezoelectric measurements showed similar trends. All vials passed physical container closure integrity testing, and no stopper rupture was seen with any of the settings applied, suggesting that container closure integrity was warranted for the studied container closure system with the chosen capping setting ranges. LAY ABSTRACT: The vial capping process is a critical unit operation during drug product manufacturing, as it could possibly generate cosmetic defects or even affect container closure integrity. Yet there is significant variability in capping equipment and processes, and their relation to potential defects or container closure integrity has not been thoroughly studied. In this study we applied several methods—residual seal force tester, a self-developed system of a piezo force sensor measurement, and computed tomography—to characterize different container closure system combinations that had been sealed using different capping process parameter settings. The residual seal force tester can analyze a variety of different container closure systems independent of the capping equipment. An adequate and safe residual seal force range for each container closure system configuration can be established with the residual seal force tester and additional methods like computed tomography scans and leak testing. In the residual seal force range studied, the physical container closure integrity of the container closure system was warranted.

Drug Substance Frozen Storage and Thawing

Preservation through freezing is routinely used in the food industry. The same strategy can also be applied to biotechnology protein based drugs. However, in this case, careful considerations must be given to the process as the freeze and thaw operations put additional stresses on the protein, which may have negative impact on its function. In this chapter, we present a Quality by Design (QbD) approach for handling the risks associated with a commercial production freeze-thaw process for recombinant protein drug substances. A brief treatment on the physics of freezing and thawing is given, followed by a description of the commercial freeze-thaw unit operation and associated equipment. The QbD risk-based strategy is then discussed in detail. The overall approach is illustrated through a case study that shows how small-scale models are leveraged for characterization of freeze-thaw production process.

Split-cakes, still delicious

“Elegant” lyophilized pharmaceutical product cakes are expected to appear as uniform foamy plugs with little shrinkage and minimal cracking. While studying internal cake structures, we have on occasion observed some cakes that were very sharply split horizontally, roughly in halves, with foamy top and lamellar bottom regions. After many years and numerous experiments, we can finally propose a mechanism for the formation of these cakes with unusual internal structures. This phenomenon involves a complex interplay of momentum, heat, mass transfer, and phase equilibria. LAY ABSTRACT: Freeze drying (lyophilization) is a common unit operation in the manufacturing of pharmaceutical drugs. The typical final lyophilized product is expected to look like a uniform porous plug, or cake, that has foamy (sponge-like) morphology. However, we have occasionally observed cakes that were split horizontally, with the top and bottom layers exhibiting very distinctive and totally different structures. This intriguing phenomenon has not been discussed in the literature. In this report, we present experimental results that lead us to a mechanism by which split-cakes form.

Chemical Durability of Glass—Delamination

Primary packaging containers used for the storage of parenteral drugs are designed to protect the medicinal product from the environment to ensure patient safety. Mainly borosilicate glasses are leveraged as the vial material of choice due to their excellent chemical durability and other additional benefits. Nevertheless, the formulation and its excipients can interact with the glass leading to an alteration of the surface. This interaction can result in ion leaching or glass corrosion. One prominent example is the occurrence of delamination which is the formation of glass flakes/lamellae. Such visible particles were the reason for several recalls within the last years. For that reason, an overview of general interaction mechanisms of the formulation with the glass surface and the root cause for delamination is presented within this chapter. Factors influencing the risk for delamination are discussed in detail as well as analytical techniques suited to investigate the impact on the properties of the primary packaging containers. The combination of the knowledge about the underlying root cause and the respective analytical tools to characterize the vial internal surfaces will help both the manufacturers of the vials and the pharmaceutical companies to establish a thorough control strategy to avoid the issue of delamination.

The Pharmaceutical Capping Process—Correlation between Residual Seal Force, Torque Moment, and Flip-off Removal Force

The majority of parenteral drug products are manufactured in glass vials with an elastomeric rubber stopper and a crimp cap. The vial sealing process is a critical process step during fill-and-finish operations, as it defines the seal quality of the final product. Different critical capping process parameters can affect rubber stopper defects, rubber stopper compression, container closure integrity, and also crimp cap quality. A sufficiently high force to remove the flip-off button prior to usage is required to ensure quality of the drug product unit by the flip-off button during storage, transportation, and until opening and use. Therefore, the final product is 100% visually inspected for lose or defective crimp caps, which is subjective as well as time- and labor-intensive. In this study, we sealed several container closure system configurations with different capping equipment settings (with corresponding residual seal force values) to investigate the torque moment required to turn the crimp cap. A correlation between torque moment and residual seal force has been established. The torque moment was found to be influenced by several parameters, including diameter of the vial head, type of rubber stopper (serum or lyophilized) and type of crimp cap (West® or Datwyler®). In addition, we measured the force required to remove the flip-off button of a sealed container closure system. The capping process had no influence on measured forces; however, it was possible to detect partially crimped vials. In conclusion, a controlled capping process with a defined target residual seal force range leads to a tight crimp cap on a sealed container closure system and can ensure product quality. LAY ABSTRACT: The majority of parenteral drug products are manufactured in a glass vials with an elastomeric rubber stopper and a crimp cap. The vial sealing process is a critical process step during fill-and-finish operations, as it defines the seal quality of the final product. An adequate force to remove the flip-off button prior to usage is required to ensure product quality during storage and transportation until use. In addition, the complete crimp cap needs to be fixed in a tight position on the vial. In this study, we investigated the torque moment required to turn the crimp cap and the force required to remove the flip-off button of container closure system sealed with different capping equipment process parameters (having different residual seal force values).

The pharmaceutical vial capping process: Container closure systems, capping equipment, regulatory framework, and seal quality tests.

Parenteral drug products are protected by appropriate primary packaging to protect against environmental factors, including potential microbial contamination during shelf life duration. The most commonly used CCS configuration for parenteral drug products is the glass vial, sealed with a rubber stopper and an aluminum crimp cap. In combination with an adequately designed and controlled aseptic fill/finish processes, a well-designed and characterized capping process is indispensable to ensure product quality and integrity and to minimize rejections during the manufacturing process. In this review, the health authority requirements and expectations related to container closure system quality and container closure integrity are summarized. The pharmaceutical vial, the rubber stopper, and the crimp cap are described. Different capping techniques are critically compared: The most common capping equipment with a rotating capping plate produces the lowest amount of particle. The strength and challenges of methods to control the capping process are discussed. The residual seal force method can characterize the capping process independent of the used capping equipment or CCS. We analyze the root causes of several cosmetic defects associated with the vial capping process.