The Influence of Moisture Content and Temperature on the Long-Term Storage Stability of Freeze-Dried High Concentration Immunoglobulin G (IgG)

Storage conditions affect the composition of the lyophilized secretome of multipotent mesenchymal stromal cells

The widespread use of multipotent mesenchymal stromal cell-derived secretome (MSC-sec) requires optimal preservation methods. Lyophilization offers benefits like concentrating the secretome, reducing the storage volume, and making storage conditions more flexible. This study evaluated the influence of storage duration and temperature on lyophilized MSC-sec. The conditioned medium from Wharton's jelly MSCs was stored at - 80 °C or lyophilized with or without trehalose. Lyophilized formulations were kept at - 80 °C, - 20 °C, 4 °C, or room temperature (RT) for 3 and 30 months. After storage and reconstitution, the levels of growth factors and cytokines were assessed using multiplex assay. The storage of lyophilized MSC-sec at - 80 °C ensured biomolecule preservation for 3 and 30 months. Following 3 month storage at 4 °C and RT, a notable decrease occurred in BDNF, bNGF, and sVCAM-1 levels. Prolonged 30 month storage at the same temperatures significantly reduced BDNF, bNGF, VEGF-A, IL-6, and sVCAM-1, while storage at - 20 °C decreased BDNF, bNGF, and VEGF- A levels. Trehalose supplementation of MSC-sec improved the outcome during storage at 4 °C and RT. Proper storage conditions were crucial for the preservation of lyophilized MSC-sec composition. Short-term storage at various temperatures maintained over 60% of the studied growth factors and cytokines; long-term preservation was only adequate at -80 °C.

Essential considerations towards development of effective nasal antibiotic formulation: features, strategies, and future directions

INTRODUCTION

Intranasal antibiotic products are gaining popularity as a promising method of administering antibiotics, which provide numerous benefits, e.g. enhancing drug bioavailability, reducing adverse effects, and potentially minimizing resistance threats. However, some issues related to the antibiotic substances and nasal route challenges must be addressed to prepare effective formulations.

AREAS COVERED

This review focuses on the valuable points of nasal delivery as an alternative route for administering antibiotics, coupled with the challenges in the nasal cavity that might affect the formulations. Moreover, this review also highlights the application of nasal delivery to introduce antibiotics for local therapy, brain targeting, and systemic effects that have been conducted. In addition, this viewpoint provides strategies to maintain antibiotic stability and several crucial aspects to be considered for enabling effective nasal formulation.

EXPERT OPINION

In-depth knowledge and understanding regarding various key considerations with respect to the antibiotic substances and nasal route delivery requirement in preparing effective nasal antibiotic formulation would greatly improve the development of nasally administered antibiotic products, enabling better therapeutic outcomes of antibiotic treatment and establishing appropriate use of antibiotics, which in turn might reduce the chance of antibiotic resistance and enhance patient comfort.

Process and isothermal storage stabilities of a live veterinary vaccine formulated with Plectranthus esculentus tuber starch derivatives as stabilizers

Comparability stability studies of a live Newcastle Disease LaSota vaccine were conducted post freeze-drying and during storage at 5±2, 25±2 and 37±1 °C to demonstrate the equivalence/inequivalence of stability profiles of vaccines stabilized with peptone (reference), trehalose and starch derivatives (acetylated xerogel and carboxymethylated) from Plectranthus esculentus tubers. Variations in moisture content during storage at 5±2 °C; physical collapse/shrinkage, partial microcollapse, and hydrophilicity of lyophilisates were prominent in starch stabilized vaccines without additives. Using the mean embryo infective dose (EID50) test, the derivatives and peptone stabilized vaccines had < 0.5 logEID50 loss in titre during freeze-drying. At the storage temperatures of 5±2, 25±2 and 37±1 °C, using peptone, acetylated xerogel starch, carboxymethylated starch, and trehalose, the average shelf lives of the vaccines were 23-55, 21-26, and 2.6-4.9 months respectively. Acetylated xerogel and carboxymethylated derivatives of Plectranthus esculentus tuber starch with/without additives were able to keep the live ND LaSota vaccine stable during freeze-drying at 1-3 % w/v. The stability of all the vaccines declined as storage temperatures increased. The acetylated xerogel stabilized vaccines were more stable than all of the others at 25±2 and 37±1 °C temperatures.

Quality by design-based optimization of in situ ionic-sensitive gels of amoxicillin-loaded bovine serum albumin nanoparticles for enhanced local nasal delivery

A recommended first-line acute bacterial rhinosinusitis (ABR) treatment regimen includes a high dose of orally administered amoxicillin, despite its frequent systemic adverse reactions coupled with poor oral bioavailability. Therefore, to overcome these issues, nasal administration of amoxicillin might become a potential approach for treating ABR locally. The present study aimed to develop a suitable carrier system for improved local nasal delivery of amoxicillin employing the combination of albumin nanoparticles and gellan gum, an ionic-sensitive polymer, under the Quality by Design methodology framework. The application of albumin nanocarrier for local nasal antibiotic therapy means a novel approach by hindering the nasal absorption of the drug through embedding into an in situ gelling matrix, further prolonging the drug release in the nasal cavity. The developed formulations were characterized, including mucoadhesive properties, in vitro drug release and antibacterial activities. Based on the results, 0.3 % w/v gellan gum concentration was selected as the optimal in situ gelling matrix. Essentially, each formulation adequately inhibited the growth of five common nasal pathogens in ABR. In conclusion, the preparation of albumin-based nanoparticles integrated with in situ ionic-sensitive polymer provides promising ability as nanocarrier systems for delivering amoxicillin intranasally for local antibiotic therapy.

Enhanced powder dispersion of dual-excipient spray-dried powder formulations of a monoclonal antibody and its fragment for local treatment of severe asthma

The advent of biologics has brought renewed hope for patients with severe asthma, a condition notorious for being hampered by poor response to conventional therapies and adverse drug reactions owing to corticosteroid dependence. However, biologics are administered as injections, thereby precluding the benefits inhalation therapy could offer such as increased bioavailability at the site of action, minimal systemic side effects, non-invasiveness, and self-administration. Here, 2-hydroxypropyl-beta-cyclodextrin and ʟ-leucine were co-spray-dried, as protein stabiliser and dispersion enhancer, respectively, at various weight ratios to produce a series of formulation platforms. Powder aerosolisation characteristics and particle morphology were assessed for suitability for pulmonary delivery. The selected platform with the best aerosol performance, a 1:1 ratio of the excipients, was then incorporated with a monoclonal antibody directed against IL-4 receptor alpha or its antigen-binding fragment. The dual-excipient antibody formulations exhibited emitted fraction of at least 80% and fine particle fraction exceeding 60% in cascade impactor study, while the residual moisture content was within a desirable range between 1% and 3%. The in vitro antigen-binding ability and inhibitory potency of the spray-dried antibody were satisfactorily preserved. The results from this study corroborate the viability of inhaled solid-state biomacromolecules as a promising treatment approach for asthma.

Drug Shelf Life and Release Limits Estimation Based on Manufacturing Process Capability

Specification limits are the competence regulatory agencies, whereas the release limit is a manufacturer’s internal specification to be applied at the time of batch release to assure that quality attributes will remain within the specification limits until the expiry time. The aim of this work is to propose a method to set the shelf life from drug manufacture process capacity and degradation rate, using a modified version of the proposed method by Allen et al. (1991) Two different data sets were used to do this. The first data set corresponds to analytical method validation to measure the insulin concentration in order to estimate the specification limits, whereas the latter set gathered information on stability data of six batches of human insulin pharmaceutical preparation. In this context, the six batches were divided into two groups: Group 1 (batches 1, 2, and 4) was used to estimate shelf life; Group 2 (batches 3, 5, and 6) was used to test the estimated lower release limit (LRL). The ASTM E2709-12 approach was applied to verify that the future batches fulfill the release criterium. The procedure has been implemented in R-code.

Part I: Significant reduction of lyophilization process times by using novel matrix based scaffolds

To improve the long-term stability of drugs with limited stability (e.g., biologicals such as monoclonal antibodies, antibody drug conjugates or peptides), some pharmaceuticals endure a lengthy and cost-intensive process called lyophilization. While the shelf life of lyophilized drugs may be prolonged compared to their liquid form, the drawbacks come in the form of intensified manufacturing, preparation, and dosing efforts. The use of glass vials as the primary container unit for lyophilized products hinders their complication-free, fast and flexible use, as they require a skilled healthcare professional and an aseptic environment in which to prepare them. The feasibility of substituting glass vials with novel container designs offering the complete transfer of the lyophilizate cake into modern administration devices, while reducing the economic footprint of the lyophilization process, was investigated. The lyophilization process of a monoclonal antibody solution was studied by assessing primary drying conditions, homogeneity of the drying process, and critical quality attributes after successful lyophilization. The creation of novel container designs utilized vacuum-forming to generate confined containers with removable bottoms and rapid prototyping, including subtractive and additive manufacturing methods, to generate porous 3D structures for drug housing. The novel container designs generated lyophilizates twice as fast and achieved a threefold faster reconstitution compared to their vial counterparts, without adaptation of the processing conditions. We conclude that the use of intermediate process containers offers significant relief for healthcare professionals in terms of reduced probability of handling errors, while drug manufacturers benefit from the accelerated processing times, increased batch homogeneity, and sustainability.

Accelerated Storage for Shelf-Life Prediction of Lyophiles: Temperature Dependence of Degradation of Amorphous Small Molecular Weight Drugs and Proteins

Prediction of lyophilized product shelf-life using accelerated stability data requires understanding the temperature dependence of the degradation rate. Despite the abundance of published studies on stability of freeze-dried formulations and other amorphous materials, there are no definitive conclusions on the type of pattern one can expect for the temperature dependence of degradation. This lack of consensus represents a significant gap which may impact development and regulatory acceptance of freeze-dried pharmaceuticals and biopharmaceuticals. Review of the literature demonstrates that the temperature dependence of degradation rate constants in lyophiles can be represented by the Arrhenius equation in most cases. In some instances there is a break in the Arrhenius plot around the glass transition temperature or a related characteristic temperature. The majority of the activation energies (E_a), which are reported for various degradation pathways in lyophiles, falls in the range of 8 to 25 kcal/mol. The degradation E_a values for lyophiles are compared with the E_a for relaxation processes and diffusion in glasses, as wells as solution chemical reactions. Collectively, analysis of the literature demonstrates that the Arrhenius equation represents a reasonable empirical tool for analysis, presentation, and extrapolation of stability data for lyophiles, provided that specific conditions are met.

Enhanced Stability of Vegetal Diamine Oxidase with Trehalose and Sucrose as Cryoprotectants: Mechanistic Insights

Enteric dysfunctions are common for various histamine-related intestinal disorders. Vegetal diamine oxidase (vDAO), an enzyme able to decompose histamine and thus alleviate histamine-related dysfunctions, was formulated in gastro-resistant tablet forms for oral administration as a food supplement and possible therapeutic agent. A major challenge for the use of proteins in the pharmaceutical field is their poor stability. In this study, vDAO was freeze-dried in the absence or in the presence of sucrose or trehalose as cryoprotectants and then formulated as tablets by direct compression. The stability of the obtained preparations was followed during storage at 4 °C and -20 °C for 18 months. In vitro dissolution tests with the vDAO powders formulated as tablets were performed in simulated gastric and in simulated intestinal fluids. The tablets obtained with the powder of the vDAO lyophilized with sucrose or trehalose cryoprotectants offered better protection for enzyme activity. Furthermore, the release of the vDAO lyophilized with the cryoprotectants was around 80% of the total loaded activity (enzyme units) compared to 20% for the control (vDAO powder prepared without cryoprotectants). This report revealed the potential of sucrose and trehalose as cryoprotectants to protect vDAO from freeze-drying stress and during storage, and also to markedly improve the vDAO release performance of tablets obtained with vDAO powders.

Recent progress in drying technologies for improving the stability and delivery efficiency of biopharmaceuticals

Background

Most biopharmaceuticals are developed in liquid dosage forms that are less stable than solid forms. To ensure the stability of biopharmaceuticals, it is critical to use an effective drying technique in the presence of an appropriate stabilizing excipient. Various drying techniques are available for this purpose, such as freeze drying or lyophilization, spray drying, spray freeze-drying, supercritical fluid drying, particle replication in nonwetting templates, and fluidized bed drying.

Area covered

In this review, we discuss drying technologies and their applications in the production of stable solid-state biopharmaceuticals, providing examples of commercially available products or clinical trial formulations. Alongside this, we also review how different analytical methods may be utilized in the evaluation of aerosol performance and powder characteristics of dried protein powders. Finally, we assess the protein integrity in terms of conformational and physicochemical stability and biological activity.

Expert opinion

With the aim of treating either infectious respiratory diseases or systemic disorders, inhaled biopharmaceuticals reduce both therapeutic dose and cost of therapy. Drying methods in the presence of optimized protein/stabilizer combinations, produce solid dosage forms of proteins with greater stability. A suitable drying method was chosen, and the process parameters were optimized based on the route of protein administration. With the ongoing trend of addressing deficiencies in biopharmaceutical production, developing new methods to replace conventional drying methods, and investigating novel excipients for more efficient stabilizing effects, these products have the potential to dominate the pharmaceutical industry in the future.

Quercetin-Loaded Mesoporous Silica Nanoparticle-Based Lyophilized Tablets for Enhanced Physicochemical Features and Dissolution Rate: Formulation, Optimization, and In Vitro Evaluation

Mesoporous silica nanoparticles (MSNPs) have been proposed as a potential approach for stabilizing the amorphous state of poorly water-soluble actives. This study aimed to improve the physiochemical characteristics of poorly water-soluble quercetin (QT) through a novel lyophilized formulation. Various parameters, including solvent polarity, QT-carrier mass ratio, and adsorption time, were studied to improve the loading of QT into MSNPs. The optimized loaded MSNPs were formulated into lyophilized tablets through a freeze-drying process using hydrophilic polyvinylpyrrolidone (PVP-K30) as a polymeric stabilizer and water-soluble sucrose as a cryoprotectant. The effect of PVP-K30 and sucrose on the particle size, disintegration time, friability, and time required to release 90% of QT were studied using 3² full factorial design. The optimized formula was characterized using different evaluating techniques; for instance, differential scanning calorimetry, X-ray diffractometry, Fourier transform infrared spectroscopy, drug content, moisture content, and saturation solubility. The analysis proved that QT was consistently kept in the nanosize range with a narrow size distribution. The loaded silica nanoparticles and the optimized formulation are in an amorphous state devoid of any chemical interaction with the silica matrix or the lyophilization excipients. The optimized formula also featured low friability (less than 1%), fast disintegration (< 30 s), and a pronounced enhancement in saturation solubility and dissolution rate. Briefly, we established that the lyophilized MSNPs-based tablet would be a potential strategy for improving the rate of dissolution and, ultimately, the bioavailability of the poorly water-soluble QT.

Accelerated water removal from frozen thin films containing bacteria

Freeze-drying, or lyophilization, is widely used to produce pharmaceutical solids that contain temperature-sensitive materials. Herein, using Escherichia coli as a model live organism, whose viability in dry powders is highly sensitive to the water content in the powders, we demonstrated that the drying rate from the frozen thin films generated by thin-film freezing (TFF) is significantly faster than from the bulk frozen solids in conventional shelf freeze-drying. This is likely because the loosely stacked frozen thin films provided a larger solid-air interface and the low thickness of the thin films provided a low mass transfer resistance. The highly porous microstructure and high specific surface area of the thin-film freeze-dried powders may also be related to the faster drying observed. Moreover, we demonstrated that TFF can be applied to produce dry powders of E. coli, a Gram-negative bacterium, or Lactobacillus acidophilus, a Gram-positive bacterium, with minimum bacterial viability loss (i.e., within one log reduction). It is concluded that the TFF technology is promising in accelerating water removal from frozen samples.

Long-acting injectable formulation technologies: Challenges and opportunities for the delivery of fragile molecules

INTRODUCTION

The development of long acting injectables (LAIs) for protein and peptide therapeutics has been a key challenge over the last 20 years. If these molecules offer advantages due to their high specificity and selectivity, their controlled release may confer several additional benefits in terms of extended half-life, local delivery, and patient compliance.

AREA COVERED

This manuscript aims to give an overview of peptide and protein based LAIs from an industrial perspective, describing both approved and promising technologies (with exceptions of protein engineering strategies and devices), their advantages and potential improvements to aid their access to the market.

EXPERT OPINION

Many LAIs have been developed for peptides, with formulations on the market for several decades. On the contrary, LAIs for proteins are still far from the market and issues related to manufacturing and sterilization of these products still need to be overcome. In situ forming depots (ISFDs), whose simple manufacturing conditions and easy administration procedures (without reconstitution) are strong advantages, appear as one of the most promising technologies for the delivery of these molecules. In this regard, the approval of ELIGARD® in the early 2000's (which still requires a complex reconstitution process), paved the way for the development of second-generation, ready-to-use ISFD technologies like BEPO® and FluidCrystal®.

Effects of Autoclaving and Freeze-Drying on Physicochemical Properties of Plectranthus esculentus Starch Derivatives

The goal of this research was to assess the effects of autoclaving followed by freeze-drying on acetylated xerogel (AXS) and carboxymethylated (CMS) derivatives of Plectranthus esculentus starch as potential vaccine stabilizers. Starch extracted from tubers of P. esculentus were modified by single (carboxymethylation) and dual (acetylation followed by xerogel formation) methods. The derivatives were formulated into vaccine stabilizer suspensions, autoclaved, and freeze-dried without additives or antigen. The derivatives and freeze-dried products were assessed by physical appearance, titration, moisture content (MC), TGA, DSC, XRD, SEM, and FTIR analyses. The degrees of substitution (DS) of the CMS and AXS derivatives were 0.345 and 0.033, respectively. Modification significantly reduced the MC of the derivatives. Freeze-dried AXS (FAXS) had lower MC than freeze-dried CMS (FCMS). The lower degree of hydrophilicity/MC of AXS and FAXS was confirmed by TGA and FTIR band intensities and shifts. Reduction in DSC water desorption/evaporation enthalpies (ΔH) from - 1168.8 mJ (NaS) to - 407.48 mJ (AXS) confirmed the influence of modification on moisture. FTIR confirmed acetylation and carboxymethylation of the derivatives by the presence of 1702.9 cm^-1 and 1593 cm^-1 bands, respectively (FTIR). Increasing concentrations of the derivatives yielded uncollapsed/unshrunken lyophilisates. SEM and XRD showed that modification, autoclaving, and freeze-drying yielded beehive-like microstructures of FCMS and FAXS that were completely amorphous. Processing (autoclaving and freeze-drying), therefore, enhanced the amorphousness of the starch derivatives which is required in vaccine stability during processing and storage. These findings indicate that these starch derivatives have potential as novel vaccine stabilizers.

Stabilizing vaccines via drying: Quality by design considerations

Pandemics and epidemics are continually challenging human beings' health and imposing major stresses on the societies particularly over the last few decades, when their frequency has increased significantly. Protecting humans from multiple diseases is best achieved through vaccination. However, vaccines thermal instability has always been a hurdle in their widespread application, especially in less developed countries. Furthermore, insufficient vaccine processing capacity is also a major challenge for global vaccination programs. Continuous drying of vaccine formulations is one of the potential solutions to these challenges. This review highlights the challenges on implementing the continuous drying techniques for drying vaccines. The conventional drying methods, emerging technologies and their adaptation by biopharmaceutical industry are investigated considering the patented technologies for drying of vaccines. Moreover, the current progress in applying Quality by Design (QbD) in each of the drying techniques considering the critical quality attributes (CQAs), critical process parameters (CPPs) are comprehensively reviewed. An expert advice is presented on the required actions to be taken within the biopharmaceutical industry to move towards continuous stabilization of vaccines in the realm of QbD.

Adjustment of specific residual moisture levels in completely freeze-dried protein formulations by controlled spiking of small water volumes

The residual moisture (RM) level strongly impacts the stability of freeze-dried biopharmaceuticals. On the one hand, the RM should not be too high to keep the reaction potential of water molecules low and to avoid a decrease in the glass transition temperature through the plasticizing effect of water. On the other hand, overdrying has been described to negatively impact protein stability. Consequently, an optimal RM has to be established and justified for approval by authorities. Therefore, end products with different RM are analyzed over storage. The different RM levels are typically obtained by slightly varying the lyophilization process itself; but deviations from the original process are critical. Additionally, samples can be taken during lyophilization runs, e.g. at the end of primary drying or after the ramp into secondary drying. This, however, does not allow for good control over the RM. Here we present the adaption of a headspace water spiking technique using a microliter syringe to precisely increase and adjust the RM. This technique is suitable to reproducibly introduce water in the microliter scale to achieve RM of less than 1% [w/w] with high precision depending on the dry cake weight. In addition, we show that by using different fill volumes and cake densities, an equal three-dimensional water distribution throughout the whole cake can be achieved. Furthermore, potential limitations and risks in manual RM introduction are discussed.

Nanoencapsulation as a General Solution for Lyophilization of Labile Substrates

Protein macromolecules occur naturally at the nanoscale. The use of a dedicated nanoparticle as a lyophilization excipient, however, has not been reported. Because biopolymeric and lipid nanoparticles often denature protein macromolecules and commonly lack the structural rigidity to survive the freeze-drying process, we hypothesized that surrounding an individual protein substrate with a nanoscale, thermostable exoshell (tES) would prevent aggregation and protect the substrate from denaturation during freezing, sublimation, and storage. We systematically investigated the properties of tES, including secondary structure and its homogeneity, throughout the process of lyophilization and found that tES have a near 100% recovery following aqueous reconstitution. We then tested the hypothesis that tES could encapsulate a model substrate, horseradish peroxidase (HRP), using charge complementation and pH-mediated controlled assembly. HRP were encapsulated within the 8 nm internal tES aqueous cavity using a simplified loading procedure. Time-course experiments demonstrated that unprotected HRP loses 95% of activity after 1 month of lyophilized storage. After encapsulation within tES nanoparticles, 70% of HRP activity was recovered, representing a 14-fold improvement and this effect was reproducible across a range of storage temperatures. To our knowledge, these results represent the first reported use of nanoparticle encapsulation to stabilize a functional macromolecule during lyophilization. Thermostable nanoencapsulation may be a useful method for the long-term storage of labile proteins.

Carboxymethylated and acetylated xerogel derivatives of Plectranthus esculentus starch protect Newcastle disease vaccines against cold chain failure

Developing vaccine stabilizers from local natural sources is desirable especially if the stabilizer would enhance the ability of the antigen to withstand frequent failures in cold chains. The study was undertaken to formulate immunogenic live Newcastle Disease (ND) LaSota vaccines stabilized with modified native starches for use at cold and ambient temperatures and to assess the immunogenicity of the starch stabilized vaccines in vaccinated chickens. Native starch extracted from the tubers of Plectranthus esculentus (Family, Lamiaceae) was modified by carboxymethylation and acetylation/xerogel formation and used as vaccine stabilizers of ND LaSota virus with/without buffers/bulking excipients. Cold Chain Failure (CCF) was simulated by storing the vaccines at 5 ± 2 °C for one month then at 37 ± 1 °C for 96 h. The stability of the samples were evaluated in comparison with peptone stabilized ND vaccines using pH, residual moisture, XRD, reconstitution time, mean embryo infective dose (EID50) and haemagglutination (HA) tests. Haemagglutination inhibition was used to evaluate the efficacy of the vaccines in conferring positive serum antibody titers (≥2³ log₂) in vaccine-naïve 2-week old broilers that were orally administered a single dose of the vaccines kept at 37 ± 1 °C for 96 h and bled weekly over four weeks. Temperature, pH, moisture content and amorphousness impacted vaccine stability. Peptone stabilized vaccines were significantly less stable and most affected by temperature changes with 1.2log₁₀EID50 loss while buffered/bulked trehalose, carboxymethylated and acetylated/xerogelized starch stabilized vaccines were most stable (0.2-0.5log₁₀EID50 loss in titer) after 96 h in CCF. Buffered trehalose stabilized vaccine (TVB) had lower HA titres than peptone and starch stabilized vaccines containing D-mannitol and Na₂HPO₄. Antibody titres of vaccinated broilers were between 3.3 ± 1.398 and 8.35 ± 2.678. All the vaccines were immunogenic (HI ≥ 2³) and developed HI titres (≥2⁴) considered to be protective. Carboxymethylated and acetylated/xerogel derivatives of P. esculentus starch have a great potential as vaccine stabilizers especially in areas prone to CCF.

The Impact of Formulation Composition and Process Settings of Traditional Batch Versus Continuous Freeze-Drying On Protein Aggregation

The long-term stability of therapeutic protein products can be extended by freeze-drying. However, the freeze-drying process itself has several harmful stresses. A rationalized formulation design can significantly mitigate protein damage caused by freezing, dehydration and interfacial stresses of lyophilization and reconstitution. Recently, a continuous spin-freeze-drying concept was proposed as a more economical, controllable, flexible and qualitative alternative to batch freeze-drying. The purpose of this work is to compare spin-freeze-drying to traditional batch freeze-drying with regard to protein physical stability. The impacts of spinning, freezing and drying were investigated for both processing methods. Herewith, the interaction between these process phases and two common rational formulation strategies, (i.e. adding a disaccharide and a surfactant) was examined. Protein aggregates formed due to the process phase stresses were characterized with particle counting techniques and size exclusion chromatography. It was found that spin-freeze-drying exhibited essentially identical stresses causing comparable aggregation in all the process phases as compared to batch freeze-drying. Moreover, there were also analogous impacts of the formulation excipients. These observations led to the conclusion that similar freeze-drying formulation excipients and strategies tested for decades in batch freeze-drying of proteins can be utilized for spin-freeze-drying; in order to maintain protein stability during processing.

Spray Freeze-Drying as a Solution to Continuous Manufacturing of Pharmaceutical Products in Bulk

Pharmaceutical manufacturing is evolving from traditional batch processes to continuous ones. The new global competition focused on throughput and quality of drug products is certainly the driving force behind this transition which, thus, represents the new challenge of pharmaceutical manufacturing and hence of lyophilization as a downstream operation. In this direction, the present review deals with the most recent technologies, based on spray freeze-drying, that can achieve this objective. It provides a comprehensive overview of the physics behind this process and of the most recent equipment design.