Reconstitution Time for Highly Concentrated Lyophilized Proteins: Role of Formulation and Protein

Formulation Factors Affecting the Formation of Visible-Bubbles During the Reconstitution Process of Freeze-Dried Etanercept Formulations: Protein Concentration, Stabilizers, and Surfactants

Freeze drying is one of the common methods to extend the long-term stability of biologicals. Biological products in solid form have the advantages of convenient transportation and stable long-term storage. However, long reconstitution time and extensive visible bubbles are frequently generated during the reconstitution process for many freeze-dried protein formulations, which can potentially affect the management efficiency of staff, patient compliance, and product quality. The reconstitution time has been extensively studied, but the influence of the formulations on the formation of visible bubbles is often overlooked. This paper investigated the effect of freeze-drying formulation factors (i.e., protein concentrations, surfactant concentrations, and sucrose/mannitol compositions) on product stability and visible bubbles generated during reconstitution of freeze-dried etanercept formulations. The generating and breakup mechanisms of visible bubbles were detected via internal microstructure of cake, surface tension, and viscosity measurement. Under the same protein concentration, the formulation of mannitol mixed with sucrose in a weight ratio of 4:1 produces fewer visible bubbles during the reconstitution process compared to the formulation of sucrose with the same total mass. This has been proven to be due to the large number of smaller radius pores distributed in the pores of the freeze-dried cake of the former, while the average internal structure pores of the latter are much larger than those of the former. As an amorphous stabilizer, sucrose can ensure the long-term stability of protein and greatly reduce the generation and maintenance of foams in the reconstitution process, making it a more robust excipient for freeze-dried protein formulations.

Effects of buffers on spray-freeze-dried/lyophilized high concentration protein formulations

Solid-state protein formulations are known to exhibit enhanced storage stability compared to their liquid dosage form counterparts. pH is one of the factors affecting the stability of protein formulations. The pH of protein formulations in the solution could be influenced by the buffer used, directly impacting their solid-state stability. During lyophilization, buffer components may interact with other formulation components present in the protein formulations, causing a pH shift. This study aimed to investigate the effects of phosphate buffer and amino acid buffers (such as histidine and/or arginine) on the physical properties and accelerated storage stability of spray freeze-dried or lyophilized protein formulations. A model protein, bovine serum albumin (BSA), was used to prepare high-concentration protein formulations. The formulations consisted of BSA, trehalose, and mannitol in an 80:15:5 ratio (w/w), respectively. Various buffers were utilized in the preparation of protein formulations, and the resultant solid formulations underwent screening via accelerated stability study using size exclusion chromatography (SEC). The combination of phosphate and arginine buffers resulted in increased monomer loss in the accelerated storage stability study. Additional characterizations, including solid-state Fourier transform infrared spectroscopy (ssFTIR) and powder X-ray diffraction (PXRD), were conducted. While these analyses did not definitively elucidate the mechanism behind the observed instability, their outcomes provide valuable insights for further investigation, highlighting the need for future research in this area.

Practical advice in the development of a lyophilized protein drug product

The development of lyophilized protein drug products is a critical and complex task in the pharmaceutical industry, requiring a comprehensive understanding of the myriad of factors affecting product quality, stability, and the efficiency and robustness of the lyophilization process. This review offers practical advice on the critical aspects of lyophilized protein drug product development. Practical considerations across both the early and late stages of development are discussed, underscoring the necessity of a strategic approach from initial development through to commercialization. The review then delves into formulation optimization strategies that are essential for enhancing protein stability and the efficiency of the lyophilization process. This section outlines stable formulation design and highlights the unique considerations required for high protein concentration lyophilized drug products. It further explores the formulation strategies to enhance the lyophilization process' efficiency. Moreover, the paper examines the critical elements in selecting primary containers and closures for lyophilized drug products, focusing on vials and dual chamber systems. The analysis encompasses the effects of the container/closure's material, size, geometry, and fill volume on product quality and process efficiency. Lastly, the review provides practical considerations in lyophilization cycle development, including the design and optimization of the freezing, primary drying, and secondary drying stages to achieve a robust, scalable, and efficient lyophilization process. By offering comprehensive insights into these key areas to enhance their understanding and implementation of best practices in the field, this paper serves as a useful resource for researchers, formulators, and process engineers involved in the development of lyophilized protein drug products.

Mucoadhesive in situ nasal gel of amoxicillin trihydrate for improved local delivery: Ex vivo mucosal permeation and retention studies

Orally administered amoxicillin is recommended as the first-line treatment of acute bacterial rhinosinusitis (ABR) and given in a high-dose regimen. However, the risk of various systemic adverse reactions and low oral bioavailability are unbearable, increasing the threat of antibiotic resistance. Therefore, nasal delivery of amoxicillin can be a potential approach for effectively treating ABR locally, as well as overcoming those drawbacks. In a way to guarantee the effectiveness for local therapy in nasal cavity, the permeation and retention properties are of significant importance considerations. Accordingly, the present work aimed to investigate the characteristics with respect to the nasal applicability of the in situ gelling amoxicillin trihydrate (AMT) and further evaluate its permeability and retention properties through human nasal mucosa. The lyophilized formulations were characterized utilizing the Differential Scanning Calorimetry (DSC) and X-ray Powder Diffraction (XRPD), and also evaluated for its polarity, reconstitution time, droplet size distribution, mucoadhesive properties, and ex vivo permeability and retention studies. The results confirmed that the in situ gelling AMT formulations possess adequate mucoadhesive behavior, especially the formulation containing 0.3 % of gellan gum. Substantially, the in situ gelling AMT formulations were able to retain the drug on the surface of nasal mucosa instead of permeating across the membrane; thus, suitable for treating nasal infections locally. Altogether, the in situ gelling systems demonstrates promising abilities as a delivery platform to enhance local application of AMT within the nasal cavity.

Effect of Annealing on Visible-Bubble Formation and Stability Profiles of Freeze-Dried High Concentration Omalizumab Formulations

In the clinical application of freeze-dried highly concentrated omalizumab formulations, extensive visible bubbles (VBs) can be generated and remain for a long period of time in the reconstitution process, which greatly reduces the clinical use efficiency. It is necessary to understand the forming and breaking mechanism of VBs in the reconstitution process, which is a key factor for efficient and safe administration of biopharmaceutical injection. The effects of different thermal treatments on the volume of VBs and stability of omalizumab, mAb-1, and mAb-2 were investigated. The internal microvoids of the cake were characterized by scanning electron microscopy and mercury intrusion porosimetry. Electron paramagnetic resonance was applied to obtain the molecular mobility of the protein during annealing. A large number of VBs were generated in the reconstitution process of unannealed omalizumab and remained for a long period of time. When annealing steps were added, the volume of VBs was dramatically reduced. When annealed at an aggressive temperature (i.e., -6 °C), although the volume of VBs decreased, the aggregation and acidic species increased significantly. Thus, our observations highlight the importance of setting an additional annealing step with a suitable temperature, which contributes to reducing the VBs while maintaining the stability of the high concentration freeze-dried protein formulation.

Microwave-Assisted Freeze-Drying: Impact of Microwave Radiation on the Quality of High-Concentration Antibody Formulations

Microwave-assisted freeze-drying (MFD) offers significant time savings compared to conventional freeze-drying (CFD). While a few studies have investigated the stability of biopharmaceuticals with low protein concentrations after MFD and storage, the impact of MFD on high-concentration monoclonal antibody (mAb) formulations remains unclear. In this study, we systematically examined the effect of protein concentration in MFD and assessed protein stability following MFD, CFD, and subsequent storage using seven protein formulations with various stabilizers and concentrations. We demonstrated that microwaves directly interact with the active pharmaceutical ingredient (API), leading to decreased physical stability, specifically aggregation, in high-concentration antibody formulations. Furthermore, typically used sugar:protein ratios from CFD were insufficient for stabilizing mAbs when applying microwaves. We identified the intermediate drying phase as the most critical for particle formation, and cooling the samples provided some protection for the mAb. Our findings suggest that MFD technology may not be universally applicable to formulations well tested in CFD and could be particularly beneficial for formulations with low API concentrations requiring substantial amounts of glass-forming excipients, such as vaccines and RNA-based products.

Mannitol as an Excipient for Lyophilized Injectable Formulations

The review summarizes the current state of knowledge of mannitol as an excipient in lyophilized injectable small and large molecule formulations. When compared with glycine, the physicochemical properties of mannitol make it a desirable and preferred bulking agent. Though mannitol is a popular bulking agent in freeze-dried formulations, its use may pose certain challenges such as vial breakage or its existence as a metastable crystalline hemihydrate in the final cake, necessitating appropriate mitigation strategies. The understanding of the phase behavior of mannitol in aqueous systems, during the various stages of freeze-drying, can be critical for the optimization of freeze-drying cycle parameters in multi-component formulations. Finally, using a decision tree as a guiding tool, we demonstrate the use of orthogonal techniques for attaining a stable and cost-effective lyophilized drug product containing mannitol.

Recent advances and persistent challenges in the design of freeze-drying process for monoclonal antibodies

Monoclonal antibodies constitute nowadays an important therapeutic class and the number of approved molecules for clinical uses continues to increase, achieving considerable part of the therapeutic market. Yet, the stability in solution of these biopharmaceuticals is often low. That's why freeze-drying has been and remains the method of choice to obtain monoclonal antibodies in the solid state and to improve their stability. The design of freeze-drying process and its optimization are still topical subjects of interest and the pharmaceutical industry is regularly challenged by the requirements of quality, safety and efficiency set by the regulatory authorities. These requirements imply a deep understanding of each step of the freeze-drying process, developing techniques to control the critical parameters and to monitor the quality of the intermediate and the final product. In addition to quality issues, the optimization of the freeze-drying process in order to reduce the cycle length is of great interest since freeze-drying is known to be an energy-expensive and time consuming process. In this review, we will present the recent literature dealing with the freeze-drying of monoclonal antibodies and focus on the process parameters and strategies used to improve the stability of these molecules and to optimize the FD process.

IMPACT OF ANNEALING AND CONTROLLED ICE NUCLEATION ON PROPERTIES OF A LYOPHILIZED 50 MG/ML MAB FORMULATION

We compared "ice-fog" controlled ice nucleation at -6 °C to annealing at the same temperature for a 50 mg/mL monoclonal antibody formulation, using shelf-ramp freezing as a control. Cake structure, drying time, reconstitution time, specific surface area, calculated cake resistance and size exclusion chromatography were all compared. Controlled nucleation resulted in the fastest reconstitution, shortest primary drying, lowest calculated cake resistance, lowest specific surface area and highest moisture content. There was no effect upon the results for size exclusion chromatography. Results for annealing were between those for controlled nucleation and shelf-ramp freezing. All results were consistent with "ice-fog" controlled nucleation at -6 °C having greater impact upon the ice crystal morphology than annealing at the same temperature for 3 hours.

Spin Freezing and Its Impact on Pore Size, Tortuosity and Solid State

Spin freeze-drying, as a part of a continuous freeze-drying technology, is associated with a much higher drying rate and a higher level of process control in comparison with batch freeze-drying. However, the impact of the spin freezing rate on the dried product layer characteristics is not well understood at present. This research focuses on the relation between spin-freezing and pore size, pore shape, dried product mass transfer resistance and solid state of the dried product layer. This was thoroughly investigated via high-resolution X-ray micro-computed tomography (µCT), scanning electron microscopy (SEM), thermal imaging and solid state X-ray diffraction (XRD). It was concluded that slow spin-freezing rates resulted in the formation of highly tortuous structures with a high dried-product mass-transfer resistance, while fast spin-freezing rates resulted in lamellar structures with a low tortuosity and low dried-product mass-transfer resistance.

Ongoing Challenges to Develop High Concentration Monoclonal Antibody-based Formulations for Subcutaneous Administration: Quo Vadis?

Although many subcutaneously (s.c.) delivered, high-concentration antibody formulations (HCAF) have received regulatory approval and are widely used commercially, formulation scientists are still presented with many ongoing challenges during HCAF development with new mAb and mAb-based candidates. Depending on the specific physicochemical and biological properties of a particular mAb-based molecule, such challenges vary from pharmaceutical attributes e.g., stability, viscosity, manufacturability, to clinical performance e.g., bioavailability, immunogenicity, and finally to patient experience e.g., preference for s.c. vs. intravenous delivery and/or preferred interactions with health-care professionals. This commentary focuses on one key formulation obstacle encountered during HCAF development: how to maximize the dose of the drug? We examine methodologies for increasing the protein concentration, increasing the volume delivered, or combining both approaches together. We discuss commonly encountered hurdles, i.e., physical protein instability and solution volume limitations, and we provide recommendations to formulation scientists to facilitate their development of s.c. administered HCAF with new mAb-based product candidates.

Additive manufacturing in drug delivery: Innovative drug product design and opportunities for industrial application

Additive manufacturing (AM) or 3D printing is enabling new directions in product design. The adoption of AM in various industrial sectors has led to major transformations. Similarly, AM presents new opportunities in the field of drug delivery, opening new avenues for improved patient care. In this review, we discuss AM as an innovative tool for drug product design. We provide a brief overview of the different AM processes and their respective impact on the design of drug delivery systems. We highlight several enabling features of AM, including unconventional release, customization, and miniaturization, and discuss several applications of AM for the fabrication of drug products. This includes products that have been approved or are in development. As the field matures, there are also several new challenges to broad implementation in the pharmaceutical landscape. We discuss several of these from the regulatory and industrial perspectives and provide an outlook for how these issues may be addressed. The introduction of AM into the field of drug delivery is an enabling technology and many new drug products can be created through productive collaboration of engineers, materials scientists, pharmaceutical scientists, and industrial partners.

Stabilizers and their interaction with formulation components in frozen and freeze-dried protein formulations

This review aims to provide an overview of the current knowledge on protein stabilization during freezing and freeze-drying in relation to stress conditions commonly encountered during these processes. The traditional as well as refined mechanisms by which excipients may stabilize proteins are presented. These stabilizers encompass a wide variety of compounds including sugars, sugar alcohols, amino acids, surfactants, buffers and polymers. The rational selection of excipients for use in frozen and freeze-dried protein formulations is presented. Lyophilized protein formulations are generally multicomponent systems, providing numerous possibilities of excipient-excipient and protein-excipient interactions. The interplay of different formulation components on the protein stability and excipient functionality in the frozen and freeze-dried systems are reviewed, with discussion of representative examples of such interactions.

Key factors governing the reconstitution time of high concentration lyophilized protein formulations

Lyophilized protein formulations containing highly concentrated proteins often have long and variable reconstitution times. Reconstitution time is dependent on a number of factors in a complex manner. Furthermore, factors influencing the reconstitution of partially crystalline cakes are reportedly different from those of amorphous cakes. The objectives of this work were to identify the key factors governing reconstitution and understand the mechanisms involved in reconstitution of both amorphous and partially crystalline cakes. Partial crystallinity in the final cake, larger pores and low "concentrated formulation viscosity" (i.e., viscosity near the surface of the dissolving cake) were identified as desirable characteristics for expediting reconstitution. Crystallinity and larger pores dramatically improved wettability and liquid penetration into partially crystalline cakes, ultimately resulting in well dispersed small pieces of partially dissolved cake. The smaller disintegrated cake pieces dissolved faster because of the increased surface area. The amorphous cakes exhibited poorer wettability than partially crystalline cakes. Moreover, the ability of the reconstitution fluid to penetrate the pores, and the resulting cake disintegration was much lower than that observed for partially crystalline cakes. In fact, for some of the amorphous cakes, the reconstitution fluid did not penetrate the cake at all. As a result, the undissolved intact cake or a large cake chunk floated on the reconstitution fluid amidst foam or bubbles generated during reconstitution. Dissolution of the floating cake appeared to proceed via gradual surface erosion where reconstitution time was found to be highly correlated with the viscosity near the surface of the dissolving cake solids. A higher viscosity prolonged reconstitution. Thus, both formulation and processing conditions can be tailored to achieve faster reconstitution. Including a crystallizable excipient proved to be beneficial. Incorporating an annealing step to facilitate crystallization of the crystallizable excipient and to promote larger pores was also found to be advantageous. A viscosity lowering excipient in the formulation could potentially be helpful but needs to be explored further.