Dry storage of mammalian spermatozoa and cells: state-of-the-art and possible future directions

This review provides a snapshot of the current state-of-the-art of drying cells and spermatozoa. The major successes and pitfalls of the most relevant literature are described separately for spermatozoa and cells. Overall, the data published so far indicate that we are closer to success in spermatozoa, whereas the situation is far more complex with cells. Critical for success is the presence of xeroprotectants inside the spermatozoa and, even more so, inside cells to protect subcellular compartments, primarily DNA. We highlight workable strategies to endow gametes and cells with the right combination of xeroprotectants, mostly sugars, and late embryogenesis abundant (LEA) or similar 'intrinsically disordered' proteins to help them withstand reversible desiccation. We focus on the biological aspects of water stress, and in particular cellular and DNA damage, but also touch on other still unexplored issues, such as the choice of both dehydration and rehydration methods or approaches, because, in our view, they play a primary role in reducing desiccation damage. We conclude by highlighting the need to exhaustively explore desiccation strategies other than lyophilisation, such as air drying, spin drying or spray drying, ideally with new prototypes, other than the food and pharmaceutical drying strategies currently used, tailored for the unique needs of cells and spermatozoa.

Electrospinning With Lyophilized Platelet-Rich Fibrin Has the Potential to Enhance the Proliferation and Osteogenesis of MC3T3-E1 Cells

Platelet-rich fibrin (PRF) as a reservoir of various growth factors plays an essential role in wound healing and tissue engineering at present. Electrospinning technology is an efficient approach to acquire artificial scaffold which has large specific surface area and high porosity. The goal of this study was to investigate the potential of electrospinning on the proliferation and osteogenesis of osteogenic precursor cells in vitro, with lyophilized PRF added as a component for electrospinning preparation. The surface structure of lyophilized PRF and nanofibers were investigated, and the proliferation, osteogenesis of MEC3T3-E1 cells with lyophilized PRF or nanofibers extract were studied. The results showed that the diameters of the lyophilized PRF pores were 1.51 ± 0.75 μm, and lyophilized PRF medium promoted the proliferation and osteocalcin (OCN) and osteopontin (OPN) genes expression of MEC3T3-E1 cells. Furthermore, the diameters of the polyvinyl alcohol/sodium alginate/lyophilized PRF (PVA/SA/PRF) fibers were 201.14 ± 40.14 nm. Compared to PVA/SA nanofibers extract and control medium, PVA/SA/PRF nanofibers extract also enhanced the proliferation and mineralization activity of MEC3T3-E1 cells. These results might be instructive to future therapeutics with PVA/SA/PRF electrospinning for bone tissue engineering or other applications.

Water Vapor Pathways during Freeze-Drying of Foamed Product Matrices Stabilized by Maltodextrin at Different Concentrations

This study aimed to identify the water-vapor transport mechanisms through an aerated matrix during microwave freeze-drying. Due to the larger surface area and lower water vapor transport resistance of an aerated product compared to the solution, foam structures dry faster. Different foam structures were produced with different maltodextrin (MD) concentrations (10–40%) as a foam-stabilizing agent. Depending on the initial viscosity of the solution prior to foaming, the samples differed in overrun (41–1671%) and pore size (d50 = 58–553 µm). Experiments were partially performed in a freeze-drying chamber of a light microscope to visualize structural changes in-situ. Different mechanisms were identified explaining the accelerated drying of foams, depending on the MD concentration, above or below 30%. At lower MD concentration, high overruns could be produced prior to freezing with big bubbles and thin lamellae with short diffusion pathway length. At 40% MD concentration, the viscosity was too high to integrate much air into the product. Therefore, the foam overrun was low and the bubble size small. Under these conditions, the water vapor generates high pressure, resulting in the formation of channels between bubbles, thus creating the pathways with low resistance for a very fast water vapor mass transfer. In addition, microwave freeze-drying experiments using a pilot plant unit were conducted to validate the findings of the freeze-drying microscope. A reduction of the drying time from 150 min (10% MD) to 78 min (40% MD) was achieved.

Immobilization of vaginal Lactobacillus in polymeric nanofibers for its incorporation in vaginal probiotic products

Probiotic products require high number of viable and active microorganisms during storage. In this work, the survival of human vaginal Lactobacillus gasseri CRL1320 and Lactobacillus rhamnosus CRL1332 after nanofiber-immobilization by electrospinning with polyvinyl-alcohol, and during storage was evaluated. The optimization of bacterial immobilization and storage conditions using bioprotectors (skim milk-lactose and glycerol) and oxygen-excluding packaging was carried out, compared with lyophilization. After electrospinning, a higher survival rate of L. rhamnosus (93%) compared to L. gasseri (84%) was obtained in nanofibers, with high viable cells (>10⁷ colony-forming unit/g) of the two probiotics in nanofibers stored at -20°C up to 14 days. The storage in oxygen-excluding packaging was an excellent strategy to extend the shelf-life of L. rhamnosus (up to 1.7 × 10⁸ CFU/g) in nanofibers stored at 4°C during 360 days, with no addition of bioprotectives, resulting similar to freeze-dried-cells. L. rhamnosus was successfully incorporated into polymeric hydrophilic nanofibers with a mean diameter of 95 nm. The composite materials were characterized in terms of morphology, and their physicochemical and thermal properties assessed. Nanofiber-immobilized L. rhamnosus cells maintained the inhibition to urogenital pathogens. Thus, polymeric nanofiber-immobilized L. rhamnosus CRL1332 can be included in vaginal probiotic products to prevent or treat urogenital infections.

Spray dried VSV-vectored vaccine is thermally stable and immunologically active in vivo

Effective vaccine delivery and coverage to rural and resource-poor countries is hindered by the dependence on cold chain storage. As such, developments of cold chain-free technologies are highly sought. Although spray dried adenoviral vectors have shown long term stability at ambient temperatures and relatively low humidity, it remains to be determined whether similar excipient formulations are applicable to other viral vectors. To address this, we have spray dried vesicular stomatitis virus (VSV)-vectors with a panel of well-characterized sugar excipients to determine the optimal formulation for vector stabilization. Upon reconstitution, we show that trehalose conferred superior stability of VSV both in vitro and in vivo. Importantly, following cold chain-free storage at elevated temperatures at 37 °C for 15 days, we show that a VSV-vectored vaccine retains its in vivo immunogenicity, whereas a liquid control completely lost its immune-stimulating ability. Our results provide foundational evidence that spray drying with properly tested excipients can stabilize viral vectors such as VSV, allowing them to be stored long-term at elevated temperatures without dependency on cold chain conditions.

Screening of autochthonous vaginal beneficial lactobacilli strains by their growth at high temperatures for technological applications

The pharmaceutical industry shows an emerging interest in formulas that contain live and beneficial microorganisms, also known as probiotics or pharmabiotics, which in many cases, are host-specific. The resistance to higher temperature is an essential feature of these microorganisms when working on the design of products for vaginal formula. In order to obtain a high number of viable cells and a prolonged shelf life in the designed product, it is required to apply technological procedures using high temperatures or abrupt changes of them, which result in conditions that are different from the optimal growth temperature and can affect the metabolic capabilities of the bacteria when administered to the host in order to reestablish the ecological mucosa. The aim of this work was to evaluate the behavior of 30 different species and strains of autochthonous beneficial vaginal lactobacilli (BVL) when exposed to high temperatures, determine their survival capabilities and analyze their pre-adaptation to those temperatures, in order that they still maintain their viability after technological processes and further conservation. BVL were exhibited to temperatures higher than optimal, with the purpose of evaluating their growth kinetics and parameters. Later, they were exposed to higher temperatures, and then, returned to their optimal, to determine if they were able to grow again. The strains that showed higher resistance were selected, and their viability and beneficial properties studied further. The growth kinetics of strains exposed to higher temperatures showed different patterns, which provided evidence that the thermal adaptation is strain-dependent and is not related to any particular species and/or metabolic group in which the strains were taxonomically classified. The pre-adaptive step allowed the growth of some of the strains, preserving their viability and probiotic properties after the high temperatures were applied. The results shows that BVL can be exposed to high temperatures used in different technological processes that are applied for pharmabiotic formulations, such as spray dried or vacuum rotary evaporation, and/or during the conservation period. The results obtained indicate that some specific BVL strains resist high temperatures and grow afterwards at optimal conditions.

Freeze-Drying Formulations Increased the Adenovirus and Poxvirus Vaccine Storage Times and Antigen Stabilities

Successful vaccines induce specific immune responses and protect against various viral and bacterial infections. Noninactivated vaccines, especially viral vector vaccines such as adenovirus and poxvirus vaccines, dominate the vaccine market because their viral particles are able to replicate and proliferate in vivo and produce lasting immunity in a manner similar to natural infection. One challenge of human and livestock vaccination is vaccine stability related to the antigenicity and infectivity. Freeze-drying is the typical method to maintain virus vaccine stability, while cold chain transportation is required for temperatures about 2 °C–8 °C. The financial and technological resource requirements hinder vaccine distribution in underdeveloped areas. In this study, we developed a freeze-drying formula consisting of bovine serum albumin (BSA), l-glutamic acid (L-Glu), polyethylene glycol (PEG), and dextran (DEX) to improve the thermal stability and activity of viral vaccines, including vaccinia recombinant vaccine (rTTV-OVA) and adenovirus vaccine (Ad5-ENV). We compared a panel of five different formulations (PEG: DEX: BSA: L-GLU = 50:9:0:0(#1), 50:5:4:0(#2), 50:10:9:0(#3), 50:0:0:9(#4), and 50:1:0:8(#5), respectively) and optimized the freeze-drying formula for rTTV-OVA and Ad5-ENV. We found that the freeze-drying formulations #2 and #3 could maintain rTTV-OVA infectivity at temperatures of 4 °C and 25 °C and that rTTV-OVA immunogenicity was retained during lyophilization. However, formulations #4 and #5 maintained Ad5-ENV infectivity under the same conditions, and Ad5-ENV immunogenicity had maximum retention with freeze-drying formulation #4. In summary, we developed new freeze-drying formulations that increased virus vaccine storage times and retained immunogenicity at an ambient temperature.

Disinfection technology of hospital wastes and wastewater: Suggestions for disinfection strategy during coronavirus Disease 2019 (COVID-19) pandemic in China

Hospitals are important sources of pollutants resulted from diagnostic, laboratory and research activities as well as medicine excretion by patients, which include active component of drugs and metabolite, chemicals, residues of pharmaceuticals, radioactive markers, iodinated contrast media, etc. The discharge of hospital wastes and wastewater, especially those without appropriate treatment would expose the public in danger of infection. In particular, under the Coronavirus Disease 2019 (COVID-19) pandemic context in China, it is of great significance to reduce the health risks to the public and environment. In this study, technologies of different types of hospital wastes and wastewater disinfection have been summarized. Liquid chlorine, sodium hypochlorite, chlorine dioxide, ozone, and ultraviolet irradiation disinfection are commonly used for hospital wastewater disinfection. While incineration, chemical disinfection, and physical disinfection are commonly used for hospital wastes disinfection. In addition, considering the characteristics of various hospital wastes, the classification and selection of corresponding disinfection technologies are discussed. On this basis, this study provides scientific suggestions for management, technology selection, and operation of hospital wastes and wastewater disinfection in China, which is of great significance for development of national disinfection strategy for hospital wastes and wastewater during COVID-19 pandemic.

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.

Freeze-drying: A relevant unit operation in the manufacture of foods, nutritional products, and pharmaceuticals

Freeze-drying, a drying unit operation frequently used in food, pharmaceutical, and biopharmaceutical industries to prolong the shelf life of labile products, is an energy-intensive, time-consuming, and expensive process. Although all three steps (freezing, primary drying, and secondary drying) of freeze-drying are important, primary drying is the longest and most critical one. As sublimation during primary drying is mainly described in terms of heat and mass transfer, the present work provides extensive theoretical and experimental analyses of these processes. First, a detailed review of the current state-of-the art of freeze-drying, focusing on the drying stage, is given, which contributes to a fundamental understanding of the drying process. Second, a detailed experimental study of the drying section of the freeze-drying process is discussed, furnishing information on the relationship between input and output process parameters during the primary drying stage and thus aiding freeze-drying process design and optimization. In this regard, the influence of primary drying input parameters (i.e., shelf temperature and chamber pressure) and vial position on output parameters such as product temperature, sublimation rate, overall vial heat transfer coefficient, and resistance to mass transfer of the dried product are extensively discussed. For all combinations of shelf temperature and chamber pressure studied herein, the highest product temperature, sublimation rate, and overall vial heat transfer coefficient are observed in front edge vials, whereas the lowest values are observed in center vials. In general, the highest sublimation rate, at a given product temperature, is observed for low chamber pressure-high shelf temperature combinations.

Antioxidant Content of Frozen, Convective Air-Dried, Freeze-Dried, and Swell-Dried Chokecherries (Prunus virginiana L.)

Chokecherry (Prunus virginiana L.) is rich in bioactive molecules as phenolics, which can act as antioxidants, anti-inflammatory, anticancer, among others; however, due to its high perishability, most of this fruit is wasted. Freezing and sun drying have been the most adopted techniques to avoid its postharvest deterioration. Nevertheless, both processes have presented some drawbacks as high storage costs and losses of bioactive molecules. Therefore, to preserve these molecules, this study compared the impact of convective airflow drying (CAD), freezing (FR), freeze drying (FD), and swell drying (SD). Total phenolics content (TPC), total flavonoids content (TFC), kuromanin concentration (KC), and antioxidant activity (antiradical activity (ARA) and Trolox equivalent antioxidant capacity assay (TEAC)) of chokecherries were measured. “Swell drying” is a drying process coupling convective airflow drying to the Instant Controlled Pressure Drop (DIC) expansion. A central composite rotatable design was applied to optimize the DIC variables and responses. Results showed that both freezing and swell drying effectively preserve the TPC, TFC, KC, and ARA. Moreover, SD samples also presented the highest TEAC. Contrary, in the case of CAD, it caused the highest losses of both antioxidant content and activity. Swell drying remedies the shrinkage and collapsing of dried food structure, which results in a better antioxidants extraction.

Physical stability of dry powder inhaler formulations

Introduction: Dry powder inhalers (DPIs) are popular for pulmonary drug delivery. Various techniques have been employed to produce inhalation drug particles and improve the delivery efficiency of DPI formulations. Physical stability of these DPI formulations is critical to ensure the delivery of a reproducible dose to the airways over the shelf-life.Areas covered: This review focuses on the impact of solid-state stability on aerosolization performance of DPI drug particles manufactured by powder production approaches and particle-engineering techniques. It also highlights the different analytical tools that can be used to characterize the physical instability originating from production and storage.Expert opinion: A majority of the DPI literature focuses on the effects of physico-chemical properties such as size, morphology, and density on aerosolization. While little has been reported on the physical stability, particularly the stability of engineered drug particles for use in DPIs. Literature data have shown that different particle-engineering methods and storage conditions may cause physical instability of dry powders for inhalation and can significantly change the aerosol performance. A systematic examination of physical instability mechanisms in DPI formulations is necessary during formulation development in order to select the optimum formulation with satisfactory stability. In addition, the use of appropriate characterization tools is critical to detect and understand physical instability during the development of DPI formulations.

Trileucine and Pullulan Improve Anti-Campylobacter Bacteriophage Stability in Engineered Spray-Dried Microparticles

Spray drying biologics into a powder can increase thermal stability and shelf-life relative to liquid formulations, potentially eliminating the need for cold chain infrastructure for distribution in developing countries. In this study, process modelling, microparticle engineering, and a supplemented phase diagram were used to design physically stable fully amorphous spray-dried powder capable of stabilizing biological material. A greater proportion of anti-Campylobacter bacteriophage CP30A remained biologically active after spray drying using excipient formulations containing trehalose and a high glass transition temperature amorphous shell former, either trileucine or pullulan, as compared to the commonly used crystalline shell former, leucine, or a low glass transition temperature amorphous shell former, pluronic F-68. Particle formation models suggest that the stabilization was achieved by protecting the bacteriophages against the main inactivating stress, desiccation, at the surface. The most promising formulation contained a combination of trileucine and trehalose for which the combined effects of feedstock preparation, spray drying, and 1-month dry room temperature storage resulted in a titer reduction of only 0.6 ± 0.1 log₁₀(PFU mL^-1). The proposed high glass transition temperature amorphous formulation platform may be advantageous for stabilizing biologics in other spray drying applications in the biomedical engineering industry.

Freezing of Biologicals Revisited: Scale, Stability, Excipients, and Degradation Stresses

Although many biotech products are successfully stored in the frozen state, there are cases of degradation of biologicals during freeze storage. These examples are discussed in the Perspective to emphasize the fact that stability of frozen biologicals should not be taken for granted. Frozen-state degradation (predominantly, aggregation) has been linked to crystallization of a cryoprotector in many cases. Other factors, for example, protein unfolding (either due to cold denaturation or interaction of protein molecules with ice crystals), could also contribute to the instability. As a hypothesis, additional freezing-related destabilization pathways are introduced in the paper, that is, air bubbles formed on the ice crystallization front, and local pressure and mechanical stresses due to volume expansion during water-to-ice transformation. Furthermore, stability of frozen biologicals can depend on the sample size, via its impact on the freezing kinetics (i.e., cooling rates and freezing time) and cryoconcentration effects, as well as on the mechanical stresses associated with freezing. We conclude that, although fundamentals of freezing processes are fairly well described in the current literature, there are important gaps to be addressed in both scientific foundations of the freezing-related manufacturing processes and implementation of the available knowledge in practice.

Spray-dried anti-Campylobacter bacteriophage CP30A powder suitable for global distribution without cold chain infrastructure

Campylobacter jejuni is a leading cause of foodborne illness globally. In this study, a spray drying and packaging process was developed to produce a thermally-stable dry powder containing bacteriophages that retains biological activity against C. jejuni after long distance shipping at ambient temperature. Spray drying using a twin-fluid atomizer resulted in significantly less (p < 0.05) titer reduction than spray drying using a vibrating mesh nebulizer. The use of centrifugation and dilution of filtered bacteriophage lysate in the formulation step resulted in a significantly greater (p < 0.05) proportion of bacteriophages remaining active relative to use of no centrifugation and dilution. The spray-dried bacteriophage powder generated using leucine and trehalose as excipients was flowable, non-cohesive, and exhibited a high manufacturing yield. The powder retained its titer with no significant differences (p > 0.05) in biological activity after storage in suitable packaging for at least 3 weeks at room temperature and after ambient temperature shipping a total distance of approximately 19,800 km, including with a 38 °C temperature excursion. The bacteriophage powder therefore appears suitable for global distribution without the need for cold chain infrastructure.

Science and art of protein formulation development

Protein pharmaceuticals have become a significant class of marketed drug products and are expected to grow steadily over the next decade. Development of a commercial protein product is, however, a rather complex process. A critical step in this process is formulation development, enabling the final product configuration. A number of challenges still exist in the formulation development process. This review is intended to discuss these challenges, to illustrate the basic formulation development processes, and to compare the options and strategies in practical formulation development.

In situ Raman monitoring of dielectric-heating-enhanced freeze-drying under different electromagnetic wave frequencies

We studied the effect of dielectric heating on the enhancement of freeze-drying by electromagnetic waves (EMWs) under different frequencies: 2.45 GHz microwaves (MWs), and 27 and 200 MHz radio frequencies (RFs). The irradiation with RFs, particularly at 27 MHz, reduced the duration of freeze-drying by 67%. We further analysed the water structure by in situ Raman spectroscopy during freeze-drying under EMWs. The phase transition from ice to water occurred soon after starting irradiation by MWs at 2.45 GHz, while the ice phase was almost maintained at an RF of 27 MHz.

Engineering of solidified glyburide nanocrystals for tablet formulation via loading of carriers: downstream processing, characterization, and bioavailability

INTRODUCTION

Presenting poorly water-soluble drugs as nanoparticles has shown to be an effective technique in enhancing drug dissolution rate, intrinsic solubility, and thus oral bioavailability. Nevertheless, working with nanoparticles introduces many challenges, one of which is their physical instability. Formulating nanoparticles into a solid dosage form may overcome such challenges and thus unlock the potential benefits of nanosizing.

METHODS

The current work investigates the possibility of developing a novel solid dosage form, with enhanced dissolution rate, whereby nanocrystals (~400 nm) of the class II Biopharmaceutical Classification System drug, glyburide (GBD) were fabricated through combined precipitation and homogenization procedures. Using a novel, but scalable, spraying technique, GBD nanocrystals were loaded onto commonly used tablet fillers, water-soluble lactose monohydrate (LAC), and water insoluble microcrystalline cellulose (MCC). Conventional tableting processes were then used to convert the powders generated into a tablet dosage form.

RESULTS

Studies of redispersibility showed considerable preservation of size characteristics of GBD nanocrystals during downstream processing with redispersibility indices of 105 and 118 for GBD-LAC and GBD-MCC, respectively. Characterization by differential scanning calorimetry, powder X-ray diffraction, and scanning electron microscopy showed that the powders generated powders contained nanosized crystals of GBD which adhered to carrier surfaces. Powder flowability was characterized using Hausner ratio (HR) and Carr's index (CI). GBD-LAC-loaded particles exhibited poor flowability with CI and HR of 37.5% and 1.60, respectively, whilst GBD-MCC particles showed a slightly improved flowability with CI and HR of 26.47% and 1.36, respectively. The novel tablet dosage form met US Pharmacopeia specifications, including drug content, hardness, and friability.

CONCLUSION

Higher dissolution rates were observed from the nanocrystal-based tablets compared to the microsized and commercial drug formulations. Moreover, the novel nanocrystal tablet dosage forms showed enhanced in vivo performance with area under the plasma concentration- time curve in the first 24 hours values 1.97 and 2.24 times greater than that of marketed tablets.

Formulation and performance of Irbesartan nanocrystalline suspension and granulated or bead-layered dried powders - Part I

Nanocrystalline suspensions offer a promising approach to improve the dissolution rate of BCS Class II/IV drugs and hence oral bioavailability. Irbesartan (crystalline Form B), a poorly soluble drug substance was chosen as a model compound for the study. The objectives of the study were to formulate Irbesartan nanocrystalline suspension via media milling, study the effects of process and formulation variables on particle size reduction, and evaluate bead layering or spray granulation as drying processes. A Design of Experiment approach was utilized to understand the impact of formulation variables on particle size reduction via media milling. Drug concentration and type of stabilizer were found to be significant in particle size reduction. Optimized Irbesartan nanocrystalline suspension (i.e. at 10% w/w with 1% w/w poloxamer 407) showed superior in vitro dissolution profile compared to unmilled suspension. Optimized Irbesartan nanocrystalline suspension was converted into dried powders either by bead layering (with microcrystalline cellulose) or by spray granulation (either with mannitol or microcrystalline cellulose). DSC and PXRD studies revealed that Irbesartan remained crystalline post drying. Microcrystalline cellulose beads layered with Irbesartan nanocrystals showed about 65% drug dissolution within the first 10 min of dissolution study. Mannitol granules containing Irbesartan nanocrystals were fast dissolving (i.e. >90% drug dissolution within 10 min) compared to microcrystalline cellulose granules (i.e. approx. 46% drug dissolution within 10 min). Irbesartan nanocrystalline suspension had the fastest dissolution rates (i.e. >90% drug dissolution in two minutes) followed by mannitol-based granules containing dried Irbesartan nanocrystals (i.e. >90% drug dissolution in ten minutes).

Excipient selection for thermally stable enveloped and non-enveloped viral vaccine platforms in dry powders

Two enveloped viral vectors, vesicular stomatitis virus and influenza virus, and a non-enveloped viral vector, human adenovirus type 5, were encapsulated by spray drying to enhance thermal stability.Results with these candidates led to the hypothesis that stability performance of chosen excipients may be less virus-specific, as previously postulated in the literature, and more differentiated based on whether the virus has a lipid envelope. Spray dried samples were characterized for their thermal properties, RNA viability and in vitro viral activity after storage at 37 °C for up to 30 days or at 45 °C for up to 3 days. The enveloped viral vectors, as a group, were more thermally stable in trehalose while the non-enveloped viral vector showed higher activity with mannitol as the primary excipient in blends. Trehalose shows strong hydrogen bonds with the envelope's lipid membrane than the other carbohydrates, more effectively replacing water molecules while maintaining the fluidity of the membrane. Conversely, the small size of mannitol molecules was attributed to the more effective hydrogen bonding between water and the protein capsid of non-enveloped viral vectors. In all cases, a matrix with high glass transition temperature contributed to thermal stabilization through vitrification. This work suggests that carbohydrate stabilizer selection may be more dependent on the envelope rather than the specific viral vector, which, if universally true, will provide a guideline for future formulation development.

Lyophilization Process Design and Development: A Single-Step Drying Approach

High-throughput lyophilization process was designed and developed for protein formulations using a single-step drying approach at a shelf temperature (T_s) of ≥40°C. Model proteins were evaluated at different protein concentrations in amorphous-only and amorphous-crystalline formulations. Single-step drying resulted in product temperature (T_p) above the collapse temperature (T_c) and a significant reduction (of at least 40%) in process time compared to the control cycle (wherein T_p <T_c). For the amorphous-only formulation at a protein concentration of ≤25 mg/mL, single-step drying resulted in product shrinkage and partial collapse, whereas a 50 mg/mL concentration showed minor product shrinkage. The presence of a crystallizing bulking agent improved product appearance at ≤25 mg/mL protein concentration for single-step drying. No impact to other product quality attributes was observed for single-step drying. Vial type, fill height, and scale-up considerations (i.e., choked flow, condenser capacity, lyophilizer design and geometry) were the important factors identified for successful implementation of single-step drying. Although single-step drying showed significant reduction in the edge vial effect, the scale-up considerations need to be addressed critically. Finally, the single-step drying approach can indeed make the lyophilization process high throughput compared to traditional freeze-drying process (i.e., 2-step drying).

Drying Technologies for the Stability and Bioavailability of Biopharmaceuticals

Solid dosage forms of biopharmaceuticals such as therapeutic proteins could provide enhanced bioavailability, improved storage stability, as well as expanded alternatives to parenteral administration. Although numerous drying methods have been used for preparing dried protein powders, choosing a suitable drying technique remains a challenge. In this review, the most frequent drying methods, such as freeze drying, spray drying, spray freeze drying, and supercritical fluid drying, for improving the stability and bioavailability of therapeutic proteins, are discussed. These technologies can prepare protein formulations for different applications as they produce particles with different sizes and morphologies. Proper drying methods are chosen, and the critical process parameters are optimized based on the proposed route of drug administration and the required pharmacokinetics. In an optimized drying procedure, the screening of formulations according to their protein properties is performed to prepare a stable protein formulation for various delivery systems, including pulmonary, nasal, and sustained-release applications.

Mixing is required for uniform reconstitution of filter-dried protein antigens in a single-injection vaccine formulation

Ambient temperature filter dried vaccine formulations have been proposed to simultaneously achieve thermostability and offer a ready-to-use immunisation device that combines reconstitution and injection. Vaccine concentration should be uniform at the point of injection, but the uniformity following direct reconstitution of filter-dried vaccines has not been reported. We present here a study of vaccine mixing and release following dissolution of filter-dried model protein and toxoid antigens within a single syringe, filter and needle unit. Release was better for filters made from glass than cellulose. Without additional mixing, uniformity was poor and only 41% of input protein was released from protein filter-dried onto glass fiber. In contrast, adding a simple glass bead and mixing by inversion, 100% release antigen solution was achieved, with uniform concentration at exit from the needle throughout a simulated injection. Adsorption onto alum adjuvant had no detectable effect on vaccine dissolution and mixing. The uniformity and yield of low doses of diphtheria and tetanus toxoid was also improved by mixing, albeit with a lower yield of 60-68%. We conclude that uniformity and mixing should be studied to ensure safety and efficacy of directly reconstituted filter-dried vaccine formulations.

Bioavailability Enhancement of Poorly Water-Soluble Drugs via Nanocomposites: Formulation⁻Processing Aspects and Challenges

Drug nanoparticles embedded in a dispersant matrix as a secondary phase, i.e., drug-laden nanocomposites, offer a versatile delivery platform for enhancing the dissolution rate and bioavailability of poorly water-soluble drugs. Drug nanoparticles are prepared by top-down, bottom-up, or combinative approaches in the form of nanosuspensions, which are subsequently dried to prepare drug-laden nanocomposites. In this comprehensive review paper, the term &ldquo;nanocomposites&rdquo; is used in a broad context to cover drug nanoparticle-laden intermediate products in the form of powders, cakes, and extrudates, which can be incorporated into final oral solid dosages via standard pharmaceutical unit operations, as well as drug nanoparticle-laden strip films. The objective of this paper is to review studies from 2012⁻2017 in the field of drug-laden nanocomposites. After a brief overview of the various approaches used for preparing drug nanoparticles, the review covers drying processes and dispersant formulations used for the production of drug-laden nanocomposites, as well as various characterization methods including quiescent and agitated redispersion tests. Traditional dispersants such as soluble polymers, surfactants, other water-soluble dispersants, and water-insoluble dispersants, as well as novel dispersants such as wet-milled superdisintegrants, are covered. They exhibit various functionalities such as drug nanoparticle stabilization, mitigation of aggregation, formation of nanocomposite matrix⁻film, wettability enhancement, and matrix erosion/disintegration. Major challenges such as nanoparticle aggregation and poor redispersibility that cause inferior dissolution performance of the drug-laden nanocomposites are highlighted. Literature data are analyzed in terms of usage frequency of various drying processes and dispersant classes. We provide some engineering considerations in comparing drying processes, which could account for some of the diverging trends in academia vs. industrial practice. Overall, this review provides rationale and guidance for drying process selection and robust nanocomposite formulation development, with insights into the roles of various classes of dispersants.

Developments in the formulation and delivery of spray dried vaccines

Spray drying is a promising method for the stabilization of vaccines, which are usually formulated as liquids. Usually, vaccine stability is improved by spray drying in the presence of a range of excipients. Unlike freeze drying, there is no freezing step involved, thus the damage related to this step is avoided. The edge of spray drying resides in its ability for particles to be engineered to desired requirements, which can be used in various vaccine delivery methods and routes. Although several spray dried vaccines have shown encouraging preclinical results, the number of vaccines that have been tested in clinical trials is limited, indicating a relatively new area of vaccine stabilization and delivery. This article reviews the current status of spray dried vaccine formulations and delivery methods. In particular it discusses the impact of process stresses on vaccine integrity, the application of excipients in spray drying of vaccines, process and formulation optimization strategies based on Design of Experiment approaches as well as opportunities for future application of spray dried vaccine powders for vaccine delivery.

Significant Drying Time Reduction Using Microwave-Assisted Freeze-Drying for a Monoclonal Antibody

Microwave-assisted freeze-drying (MFD) is a rapid drying process well known in food technology. However, little is known about its application to biologicals. In this study, we investigated the applicability and feasibility of this technology to different monoclonal antibody formulations and the influence on the resulting product properties. Moreover, one of our main objectives was to study if significant reductions in drying times could be achieved. In addition, the effect of the drying process on the accelerated stability of a sucrose-based antibody formulation at 40°C and 25°C over 12 weeks was investigated. MFD resulted in drying time reduction >75%. For all model formulations, cake appearance and solid state properties were found to be comparable to standard lyophilized products. These formulations covered a wider range of lyophilization excipients comprising sucrose and trehalose, semi-crystalline forming solids like mannitol:sucrose mixtures and others like arginine phosphate and a mixture of 2-hydroxypropyl-β-cyclodextrin with sucrose. Moreover, comparable low changes in relative monomer content, the relative amount of soluble aggregates and cumulative particles ≥1 μm per mL were observed over 12 weeks of storage, regardless of the drying technology. This makes MFD a promising innovative alternative for the rapid production of freeze-dried biologicals while maintaining product quality.

Bulk Freeze-Drying Milling: a Versatile Method of Developing Highly Porous Cushioning Excipients for Compacted Multiple-Unit Pellet Systems (MUPS)

The compaction of multiple-unit pellet system (MUPS) is a challenging process due to the ease of coat damage under high compression pressure, thereby altering drug release rates. To overcome this, cushioning excipients are added to the tablet formulation. Excipients can be processed into pellets/granules and freeze-dried to increase their porosity and cushioning performance. However, successful formation of pellets/granules has specific requirements that limit formulation flexibility. In this study, a novel top-down approach that harnessed bulk freeze-drying milling was explored to avoid the challenges of pelletization/granulation. Aqueous dispersions containing 20%, w/w hydroxypropyl methylcellulose (HPMC), partially pregelatinised starch or polyvinylpyrrolidone alone, and with lactose (Lac) in 1:1 ratio, were freeze-dried and then milled to obtain particulate excipients for characterization and evaluation of their cushioning performance. This study demonstrated that bulk freeze-drying milling is a versatile method for developing excipients that are porous and directly compressible. The freeze-drying process modified the materials in a unique manner which could impart cushioning properties. Compared to unprocessed excipients, the freeze-dried products generally exhibited better cushioning effects. The drug release profile of drug-loaded pellets compacted with freeze-dried Lac-HPMC excipients was similar to that of the uncompacted drug-loaded pellets (f ₂ value = 51.7), indicating excellent cushioning effects. It was proposed that the specific balance of brittle and plastic nature of the freeze-dried Lac-HPMC composite conferred greater protective effect to the drug-loaded pellets, making it advantageous as a cushioning excipient.

Intra-articular delivery of tetramethylpyrazine microspheres with enhanced articular cavity retention for treating osteoarthritis

Tetramethylpyrazine (TMP) is a traditional Chinese herbal medicine with strong anti-inflammatory and cartilage protection activities, and thus a promising candidate for treating osteoarthritis. However, TMP is rapidly cleared from the joint cavity after intra-articular injection and requires multiple injections to maintain efficacy. The aim of this study was to encapsulate TMP into poly (lactic-co-glycolic acid) (PLGA) microspheres to enhance the TMP retention in the joint, reducing injection frequencies and decreasing dosage. TMP microspheres were prepared by emulsion/solvent evaporation method. The intra-articular retention of the drug was assessed by detecting the drug concentration distributed in the joint tissue at different time points. The therapeutic effect of TMP microspheres was evaluated by the swelling of knee joints and histologic analysis in papain-induced OA rat model. The prepared freeze-dried microspheres with a particle size of about 10 µm can effectively prolong the retention time of the drug in the articular cavity to 30 d, which is 4.7 times that of the TMP solution. Intra-articular injection of TMP microspheres efficiently relieved inflammatory symptoms, improved joint lesions and decreased the depletion of proteoglycan. In conclusion, intra-articular injection of TMP loaded microspheres was a promising therapeutic method in the treatment of OA.

Stability of virus-like particles of red-spotted grouper nervous necrosis virus in the aqueous state, and the vaccine potential of lyophilized particles

Virus-like particles (VLPs) are multi protein complexes mimicking the structural properties of the native virus. The development of freeze-dried formulations of such complex protein structures remains a challenge. Red-spotted grouper nervous necrosis virus (RGNNV) causes mass mortality in fish culture, and RGNNV VLPs have been suggested to be promising vaccine candidates. In the present study, the stability of RGNNV VLPs in the liquid state was investigated over a 4-week period, along with the influence of freeze-drying on VLP stability. RGNNV VLPs were completely degraded after one week at 37 °C followed by 3 weeks at ambient temperature, and they were partially degraded after 4 weeks at 4 °C. Therefore, the inherent stability of RGNNV VLP in an aqueous milieu is insufficient for long-term storage. When RGNNV VLPs were freeze-dried in the presence or absence of sugar stabilizers, sorbitol was found to improve VLP stability whereas mannitol reduced it. VLP preparations freeze-dried with sorbitol or without stabilizer were as immunogenic as control (non-freeze dried) VLPs, whereas VLPs freeze-dried in mannitol were less immunogenic. These results indicate that freeze-dried RGNNV VLPs have potential as vaccines.

Opportunity and challenges of nasal powders: Drug formulation and delivery

In the field of nasal drug delivery, among the preparations defined by the European Pharmacopoeia, nasal powders facilitate the formulation of poorly water-soluble active compounds. They often display a simple composition in excipients (if any), allow for the administration of larger drug doses and enhance drug diffusion and absorption across the mucosa, improving bioavailability compared to nasal liquids. Despite the positive features, however, nasal products in this form still struggle to enter the market: the few available on the market are Onzetra Xsail® (sumatriptan) for migraine relief and, for the treatment of rhinitis, Rhinocort® Turbuhaler® (budesonide), Teijin Rhinocort® (beclomethasone dipropionate) and Erizas® (dexamethasone cipecilate). Hence, this review tries to understand why nasal powder formulations are still less common than liquid ones by analyzing whether this depends on the lack of (i) real evidence of superior therapeutic benefit of powders, (ii) therapeutic and/or commercial interest, (iii) efficient manufacturing methods or (iv) availability of suitable and affordable delivery devices. To this purpose, the reader's attention will be guided through nasal powder formulation strategies and manufacturing techniques, eventually giving up-to-date evidences of therapeutic efficacy in vivo. Advancements in the technology of insufflation devices will also be provided as nasal drug products are typical drug-device combinations.

Microwave as an emerging technology for the treatment of biohazardous waste: A mini-review

Microwave is an emerging technology to treat biohazardous waste, including material from healthcare facilities. A screen of the peer-reviewed literature shows that only limited information may be found in this area of work and, furthermore, analysis of the references reveals that sometimes not all necessary aspects for the appropriate use of the technology are considered. Very often conventional microwave technology is applied for the inactivation of pathogens, which might make sense for certain applications but, on the other hand, may lead to the misbelief that microwave systems cannot be used for the inactivation of a solid "dry" waste. However, conventional microwave units have no means to control the inactivation process, and especially moisture content. But there are a few sophisticated microwave technologies with appropriate measurements allowing a validated inactivation of biohazardous materials. These technologies are an effective tool for inactivation and some of them are commercially available. It must also be considered that the waste should be preferably inactivated either directly at the place where it is generated or biohazardous waste should be transported only in closed systems. Moreover, microwave technology presents a possibility to save energy costs in comparison to the more widely used autoclaves. This mini-review will discuss important aspects for the use of microwave technology for the treatment of biohazardous waste.

Amorphization within the tablet: Using microwave irradiation to form a glass solution in situ

In situ amorphization is a concept that allows to amorphize a given drug in its final dosage form right before administration. Hence, this approach can potentially be used to circumvent recrystallization issues that other amorphous formulation approaches are facing during storage. In this study, the feasibility of microwave irradiation to prepare amorphous solid dispersions (glass solutions) in situ was investigated. Indomethacin (IND) and polyvinylpyrrolidone K12 (PVP) were tableted at a 1:2 (w/w) ratio. In order to study the influence of moisture content and energy input on the degree of amorphization, tablet formulations were stored at different relative humidity (32, 43 and 54% RH) and subsequently microwaved using nine different power-time combinations up to a maximum energy input of 90kJ. XRPD results showed that up to 80% (w/w) of IND could be amorphized within the tablet. mDSC measurements revealed that with increasing microwaving power and time, the fractions of crystalline IND and amorphous PVP reduced, whereas the amount of in situ formed IND-PVP glass solution increased. Intrinsic dissolution showed that the dissolution rate of the microwaved solid dispersion was similar to that of a quench cooled, fully amorphous glass solution even though the microwaved samples contained residual crystalline IND.