Automated Tomographic Assessment of Structural Defects of Freeze-Dried Pharmaceuticals.

The topology and surface characteristics of lyophilisates significantly impact the stability and reconstitutability of freeze-dried pharmaceuticals. Consequently, visual quality control of the product is imperative. However, this procedure is not only time-consuming and labor-intensive but also expensive and prone to errors. In this paper, we present an approach for fully automated, non-destructive inspection of freeze-dried pharmaceuticals, leveraging robotics, computed tomography, and machine learning.

Robust assessment of sample preparation protocols for proteomics of cells and tissues.

In proteomic studies, the reliability and reproducibility of results hinge on well-executed protein extraction and digestion protocols. Here, we systematically compared three established digestion methods for macrophages, namely filter-assisted sample preparation (FASP), in-solution, and in-gel digestion protocols. We also compared lyophilization and manual lysis for liver tissue protein extraction, each of them tested using either sodium deoxycholate (SDC)- or RIPA-based lysis buffer. For the macrophage cell line, FASP using passivated filter units outperformed the other tested methods regarding the number of identified peptides and proteins. However, a careful standardization has shown that all three methods can yield robust results across a wide range of starting material (even starting with 1 µg of proteins). Importantly, inter and intra-day coefficients of variance (CVs) were determined for all sample preparation protocols. Thus, the median inter-day CVs for in-solution, in-gel and FASP protocols were respectively 10, 8 and 9%, very similar to the median CVs obtained for the intra-day analysis (9, 8 and 8%, respectively). Moreover, FASP digestion presented 80% of proteins with a CV lower than 25%, followed closely by in-gel digestion (78%) and in-solution sample preparation (72%) protocols. For tissue proteomics, both manual lysis and lyophilization presented similar proteome coverage and reproducibility, but the efficiency of protein extraction depended on the lysis buffer used, with RIPA buffer showing better results. In conclusion, although each sample preparation method has its own particularity, they are all suited for successful proteomic experiments if a careful standardization of the sample preparation workflow is carried out.

A Simple and Cost-Effective Technique to Monitor the Sublimation Flow During Primary Drying of Freeze-Drying Using Shelf Inlet/Outlet Temperature Difference or Chamber to Condenser Pressure Drop.

As lyophilization continues to be a critical step in the manufacturing of sensitive biopharmaceuticals, challenges often arise during the scale up to commercial scale or the transfer from one manufacturing site to another. While data from the small-scale development of the lyophilization cycle is abundant it is typically much more difficult to extract important information from commercial scale cycles, due to the lack of process analytical technologies available on the commercial line. There is often a reluctance to include wireless temperature or pressure probes during GMP operations due to the additional contamination risk, and retrofitting equipment such as the TDLAS can be prohibitively expensive. Further, as products become more advanced, the cost of consuming the product or even the availability of material may limit the opportunities to run commercial scale trials. This paper presents two novel methods to garner critical cycle information to allow for the evaluation of cycle performance without the need for expensive analytical equipment, costly revalidation and line downtime. Critically, this can be achieved using commonly available temperature and capacitance probes on existing commercial scale equipment. The first method is a calorimetric method, based on quantifying the differences in heat transfer liquid temperature between the shelf inlet and shelf outlet. This change in temperature results from the on-going sublimation, an endo-thermic reaction occurring during lyophilization. The second method uses the differential pressure between the chamber and condenser resulting from the vapor flow from vial to condenser during primary drying. As stated by the authors both methods align well and provide valuable cycle characterization data.

Assessment of microwave drying for rapid and convenient analysis of medicinal plants for quality assurance.

INTRODUCTION: The safety and quality of many medicinally important herbs are compromised since farmers and small organizations are involved in the cultivation, aggregation, and primary processing of these herbs. Such organizations often lack adequate quality control facilities. To improve the safety and quality of herbal products, simple, rapid, and affordable quality control systems are required. OBJECTIVES: The aim of this study was to assess the suitability of microwave oven-drying for moisture content (MC) determination and sample preparation of herbs in small organizations. METHODS: Microwave oven-drying (720 W) and convective oven-drying at 105°C for MC determination were compared. The effects of three different drying methods (microwave oven-drying, low-temperature convective drying, and freeze-drying) on in vitro antioxidant and polyphenol oxidase (PPO) activity were determined, similarity analysis was conducted using HPLC signature spectra, and validation was performed with LC-MS focusing on one herb. RESULTS: Microwave oven-drying at 720 W significantly reduced the drying time (from hours to minutes), whereas the spatial variation of temperature in convective ovens set at 105°C can cause about 10% underestimation of MC. Microwave oven-drying showed similar macro-properties like freeze-drying and higher extractability (10%-20%) and in vitro antioxidant capacity (33%-66%) and lower PPO activity compared to low-temperature convective drying. HPLC signature spectra revealed strong similarity of soluble components between freeze-dried and microwave oven-dried herbs. LC-MS analysis demonstrated more common compounds between freeze-dried and microwave oven-dried Centella asiatica extracts, whereas convective tray-dried samples had fewer compounds common with samples obtained by freeze-drying or microwave oven-drying. CONCLUSIONS: Microwave oven-drying is rapid (tens of min) and shows small batch-to-batch variation compared to oven-drying at 105°C. The in vitro antioxidant assays and signature spectra can be used for assessing the source and purity or quality of a specific herb variety.

Assessment of freeze, continuous, and intermittent infrared drying methods for sliced persimmon.

Persimmons contribute positively to human health. Although off-season utilization typically presents a challenge due to permissions' perishable nature, it may become feasible through the implementation of appropriate drying methods. In this study, round sliced samples were dried to assess drying kinetics, modeling potential, color attributes, rehydration capacity, energy consumption (EC), cost index, and thermal properties. The fruits were subjected to distinct drying methodologies including freeze-drying, continuous infrared drying (300, 400, and 500 W), and intermittent infrared drying (PR = 1 [continuous], PR = 2 [30 s on-30 s off], and PR = 3 [20 s on-40 s off]). The duration of the drying process ranged from 40 to 390 min. It was determined that the most suitable models for depicting continuous and infrared drying kinetics of persimmon fruit were the Midilli et al. and Page models, whereas the Logarithmic model was identified as the optimal choice for characterization of freeze-drying kinetics. Assessment of EC revealed that both intermittent and continuous infrared drying methods incurred lower energy expenditure in comparison to the freeze-drying technique. Remarkably, throughout the course of the infrared drying processes, product surface temperatures varied between 106.33 and 22.65°C across different treatments. Despite its high EC, it has been found that high-quality products are produced by freeze-drying. However, infrared and intermittent infrared applications can be a low energy cost and feasible method for drying persimmon with a shorter duration. PRACTICAL APPLICATION: Persimmon is an important fruit with high nutritional value. However, as with many fresh products, they have a short shelf life. Within the scope of this research, three different drying methodologies were employed in the desiccation of persimmon specimens, and the impact of these methodologies on the overall qualitative attributes of the persimmon product was investigated. Despite its elevated energy consumption, the freeze-drying approach was found to yield high-quality products. Moreover, it was discerned that infrared drying represented a viable and expeditious alternative for drying the fruit, particularly when executed intermittently.

Freeze Drying and Vial Breakage: Misconceptions, Root Causes and Mitigation Strategies for the Pharmaceutical Industry.

Vial breakage during or following freeze drying (lyophilization) is a well-known and documented phenomenon in the pharmaceutical industry. However, the underlying mechanism and probable root causes are not well characterized. Mostly, the phenomenon is attributed to the presence of crystallizing excipients, such as mannitol in the formulation, while other potential factors are often underestimated or not well studied. In this work we document a systematic multipronged approach to characterize and identify potential root cause(s) of vial breakage during lyophilization. Factors associated with formulation, product configuration, primary container and production process stress conditions were identified and their impact on vial breakage was studied in both lab and manufacturing scale conditions. Studies included: 1) strain gauge and lyophilization analysis for stress on glass vials with different formulation conditions and fill volumes, 2) manufacturing fill-finish process risk assessment (ex. loading and frictive force impact on the vials), and 3) glass vial design and ruggedness (ex. glass compression resistance or burst strength testing). Importantly, no single factor could be independently related to the extent of vial breakage observed during production. However, a combination of formulation, fill volume, and vial weakening processes encountered during at-scale production, such as vial handling, shelf loading and unloading, were identified to be the most probable root causes for the low levels of vial breakage observed. The work sheds light on an often-encountered problem in the pharmaceutical industry and the results presented in this paper argue against the simplistic root-cause explanations reported in literature. The work also provides insight into the possibility of implementing mitigative approaches to minimize or eliminate vial breakage associated with lyophilized drug products.

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 is 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.

Practical use of primary drying models in an industrial environment with limited availability of equipment sensors.

In the pharmaceutical industry, lyophilization is typically adopted to extend long-time stability of valuable thermolabile medicines and vaccines. Primary drying is the most time-consuming and energy-intensive step of the entire process; thus, accelerating and optimizing the primary drying recipe is a key process development goal. To that purpose, mathematical models have been proposed and successfully validated. However, models typically require invasive experiments and/or sensors (e.g. product temperatures) for parameter estimation, which are rarely available in good manufacturing practice (GMP) environment. This represents a severe limitation when leveraging the model to transfer operation recipes across different facilities and for scale-up. In this study, we assess the possibility to exploit limited industrial data for model parameter estimation, namely pressure measurements and gravimetric tests, by defining a calibration protocol that is tested on two different pieces of equipment. Results are verified on a recently proposed model, and show that statistically meaningful estimates can be obtained without the need of product temperature measurements. Model predictions and optimal inputs trajectories are comparable to those obtained from the model calibrated using the full set of temperature and pressure data.

Evaluation of Packaging Materials in Freeze-Drying: Use of Polymer Caps and Nested Vials and Their Impact on Process and Product Attributes.

Current trends in the pharmaceutical industry led to a demand for more flexible manufacturing processes with smaller batch sizes. Prepackaged nested vials that can be processed as a unit were introduced into the market to fulfill this need. However, vial nests provide a different thermal environment for the vials compared to a hexagonal packaging array and could therefore influence product temperature profiles, primary drying times, and product quality attributes. Polymer caps with the possibility of vial closure inside the freeze-drying chamber were developed to remove the risks and need of a crimping process. A general concern with the use of such caps is the possibility of an increase in resistance to water vapor flow out of the vial. This case study investigated the effect of the LyoSeal® and PLASCAP® polymer caps and EZ-fill® nests on the freeze-drying process. Amorphous and partially crystalline model formulations were freeze-dried. Process data and product quality attributes were compared for regularly stoppered vials and vials with polymer caps as well as vials in a hexagonal packaging array and nested vials. The results indicated no increased resistance or impeded water vapor flow by the polymer caps. Differences in the macro- and microscopic appearances of products and a trend towards lower product temperatures were observed for the investigated nest type compared to a regular hexagonal packaging array. Consequently, the polymer caps could be used as an alternative to regular stoppers without affecting freeze-drying process data or product quality attributes, while the different thermal environment of nested vials should be considered.

Determination of ice interface temperature, sublimation rate and the dried product resistance, and its application in the assessment of microcollapse using through-vial impedance spectroscopy.

Through-vial impedance spectroscopy (TVIS) is a new approach for characterizing product attributes during freeze-drying process development. In this study, a pair of copper foil electrodes was attached to the external surface of a Type I glass tubing vial, of nominal capacity 10 mL and containing 3.5 g of an aqueous solution of 5%w/v lactose, and the impedance spectrum of the vial and contents recorded during a lyophilization cycle. The cycle included a temperature ramp in the primary drying stage in order to induce a collapse event in the dry layer. Using the peak in the dielectric loss spectrum, associated with the dielectric relaxation of ice, methods were developed to predict the sublimation rate and the ice interface temperature at the sublimation front, from which the dry layer resistance was then calculated. A four-fold increase in sublimation rate and a reduction in the dry layer resistance wereobserved once the ice interface temperature reached -33 °C, which coincides with the onset of the glass transition (as determined by DSC) and the time point at which micro-collapse occurred (as evidenced by SEM images at the end of the cycle). This work suggests a prospective application of impedance measurements in driving process efficiencies by operating the dryer at the highest achievable temperature (i.e. the collapse temperature) whilst avoiding macro-collapse.

Finding a reliable limit of detection in the NIR determination of residual moisture in a freeze-dried drug product.

The validation of an analytical method in the pharmaceutical industry follows strictly regulated guidelines. The introduction of multivariable calibration methods requires a revision of these recommendations, since some of them are contradictory regarding the limit of detection (LOD). This work compares the LOD values obtained using pseudounivariate and multivariate procedures in the PLS-NIR determination of residual moisture content (RMC) in a freeze-dried drug. As NIR has proved to be more precise than Karl-Fischer at low RMC values, LOD has been estimated by ordinary and by orthogonal least squares regression. The precision of the RMC determination in approx. 2000 industrial vials was used as an indirect evidence of the reliability of the LOD values obtained. The effect of reducing the number of calibration samples and increasing the RMC values have also been studied. No significant differences were observed using a number of calibration samples ≥ 20. Based on our findings, when the size of the calibration sample set is high and the range of RMC values is close to the limit, the LOD estimated with the ICH formula and using orthogonal regression should be recommended. If water content moves away, the ICH formula should be replaced by the LODOS equation as a practical, reliable and simple procedure.

Recent developments in high efficient freeze-drying of fruits and vegetables assisted by microwave: A review.

Microwave heating has been applied in the drying of high-value solids as it affords a number of advantages, including shorter drying time and better product quality. Freeze-drying at cryogenic temperature and extremely low pressure provides the advantage of high product quality, but at very high capital and operating costs due partly to very long drying time. Freeze-drying coupled with a microwave heat source speeds up the drying rate and yields good quality products provided the operating unit is designed and operated to achieve the potential for an absence of hot spot developments. This review is a survey of recent developments in the modeling and experimental results on microwave-assisted freeze-drying (MFD) over the past decade. Owing to the high costs involved, so far all applications are limited to small-scale operations for the drying of high-value foods such as fruits and vegetables. In order to promote industrial-scale applications for a broader range of products further research and development efforts are needed to offset the current limitations of the process. The needs and opportunities for future research and developments are outlined.

Split-Cakes, Still Delicious.

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

Developing a framework to model the primary drying step of a continuous freeze-drying process based on infrared radiation.

The continuous freeze-drying concept based on spinning the vials during freezing and on non-contact energy transfer via infrared (IR) radiation during drying, improves process efficiency and product quality (uniformity) compared to conventional batch freeze-drying. Automated control of this process requires the fundamental mechanistic modelling of each individual process step. Therefore, a framework is presented for the modelling and control of the continuous primary drying step based on non-contact IR radiation. The IR radiation emitted by the radiator filaments passes through various materials before finally reaching the spin frozen vial. The energy transfer was computed by combining physical laws with Monte Carlo simulations and was verified with experimental data. The influence of the transmission properties of various materials on the emitted IR radiation profile was evaluated. These results assist in the selection of proper materials which could serve as IR window in the continuous freeze-drying prototype. The modelling framework presented in this paper fits the model-based design approach used for the development of this prototype and shows the potential benefits of this design strategy by establishing the desired engineering parameters and by enabling the engineer to assess mechanical tolerances and material options.

Comparative evaluation of electrospraying and lyophilization techniques on solid state properties of Erlotinib nanocrystals: Assessment of In-vitro cytotoxicity.

INTRODUCTION: Erlotinib is a well known FDA approved drug from category of tyrosine kinase inhibitors; used for the treatment of lung cancer. However its use is limited because of its poor water solubility. OBJECTIVE: The aim of present work was to improve solubility by developing a stable nanocrystal based drug delivery system of ERL with the aid of sodium lauryl sulfate as potential stabilizer and to carry out comparative evaluation of electrospraying and lyophilization as solidification techniques on its solid state properties. EXPERIMENTAL: Nanocrystal formulation was developed with antisolvent precipitation method having particle size, polydispersity index and zetapotential of 232.4±4.3nm, 0.162 and -9.82mV respectively. Further comparative evaluation of lyophilization and electrospraying was commenced as potential solidification techniques and solid powder matrix obtained from both the solidification techniques were compared in terms of size after re-dispersion (260±4.8 and 329±5.2nm respectively), particle morphology, surface area (0.984±0.11 and 0.341±0.05m2/g respectively), pore volume (0.0014 and 0.0009cc/g respectively), solid state of drug present and % drug release (~100% and ~78% respectively in 600min). In vitro cytotoxicity studies shared that obtained formulation was having reduced IC50 values in comparison to drug. Further intracellular reactive oxygen species production was found to be higher for formulation treated cells when compared to free drug. Overall developed formulation was found to be potential drug delivery system for lung cancer therapy.

Quantitative risk assessment via uncertainty analysis in combination with error propagation for the determination of the dynamic Design Space of the primary drying step during freeze-drying.

Traditional pharmaceutical freeze-drying is an inefficient batch process often applied to improve the stability of biopharmaceutical drug products. The freeze-drying process is regulated by the (dynamic) settings of the adaptable process parameters shelf temperature Ts and chamber pressure Pc. Mechanistic modelling of the primary drying step allows the computation of the optimal combination of Ts and Pc in function of the primary drying time. In this study, an uncertainty analysis was performed on the mechanistic primary drying model to construct the dynamic Design Space for the primary drying step of a freeze-drying process, allowing to quantitatively estimate and control the risk of cake collapse (i.e., the Risk of Failure (RoF)). The propagation of the error on the estimation of the thickness of the dried layer Ldried as function of primary drying time was included in the uncertainty analysis. The constructed dynamic Design Space and the predicted primary drying endpoint were experimentally verified for different RoF acceptance levels (1%, 25%, 50% and 99% RoF), defined as the chance of macroscopic cake collapse in one or more vials. An acceptable cake structure was only obtained for the verification runs with a preset RoF of 1% and 25%. The run with the nominal values for the input variables (RoF of 50%) led to collapse in a significant number of vials. For each RoF acceptance level, the experimentally determined primary drying endpoint was situated below the computed endpoint, with a certainty of 99%, ensuring sublimation was finished before secondary drying was started. The uncertainty on the model input parameters demonstrates the need of the uncertainty analysis for the determination of the dynamic Design Space to quantitatively estimate the risk of batch rejection due to cake collapse.

QbD for pediatric oral lyophilisates development: risk assessment followed by screening and optimization.

OBJECTIVE: This study proposed the development of oral lyophilisates with respect to pediatric medicine development guidelines, by applying risk management strategies and DoE as an integrated QbD approach. METHODS: Product critical quality attributes were overviewed by generating Ishikawa diagrams for risk assessment purposes, considering process, formulation and methodology related parameters. Failure Mode Effect Analysis was applied to highlight critical formulation and process parameters with an increased probability of occurrence and with a high impact on the product performance. To investigate the effect of qualitative and quantitative formulation variables D-optimal designs were used for screening and optimization purposes. RESULTS: Process parameters related to suspension preparation and lyophilization were classified as significant factors, and were controlled by implementing risk mitigation strategies. Both quantitative and qualitative formulation variables introduced in the experimental design influenced the product's disintegration time, mechanical resistance and dissolution properties selected as CQAs. The optimum formulation selected through Design Space presented ultra-fast disintegration time (5 seconds), a good dissolution rate (above 90%) combined with a high mechanical resistance (above 600 g load). CONCLUSIONS: Combining FMEA and DoE allowed the science based development of a product with respect to the defined quality target profile by providing better insights on the relevant parameters throughout development process. The utility of risk management tools in pharmaceutical development was demonstrated.

A simplified ATP method for the rapid control of cell viability in a freeze-dried BCG vaccine.

We propose a simple and cost-effective ATP method for controlling the specific activity of a freeze-dried BCG vaccine. A freeze-dried BCG vaccine is reconstituted with 1ml saline and incubated for 15min at room temperature and then for 1h at 37°C. The vaccine is then treated with apyrase to remove extracellular ATP. After that, the cells are lysed with DMSO and the ATP content in the lysate is measured by the bioluminescence method. To implement the method, we developed a kit that requires no time-consuming preparation before the analysis. We demonstrated the linear relationship between the experimental values of the specific activity (106CFU/mg) and intracellular ATP content (ATP, pmol/mg) for different batches of the studied BCG vaccines; the proportionality coefficient was К=0.36±0.02. We proposed a formula for calculating the specific activity from the measured content of intracellular ATP (ATP, pmol/mg). The comparison of the measured and calculated values of the specific activity (106CFU/mg) shows that these values are similar; their differences fall within the allowable range of deviations for the specific activity values of the BCG vaccine.

Ufasomes nano-vesicles-based lyophilized platforms for intranasal delivery of cinnarizine: preparation, optimization, ex-vivo histopathological safety assessment and mucosal confocal imaging.

To circumvent the low and erratic absorption of orally administrated cinnarizine (CN), intranasal lyophilized gels containing unsaturated fatty acid liposomes (ufasomes) and encapsulating CN were prepared from oleic acid using a simple assembling strategy. The effects of varying drug concentration and cholesterol percentage on ufasomes size, polydispersity index and entrapment efficiency were investigated using 3(1)4(1) full factorial design. The optimized ufasomes that contained 14% cholesterol relative to oleic acid displayed spherical morphology with average size of 788 nm and entrapment efficiency of 80.49%. To overcome the colloidal instability of CN-loaded ufasomes dispersions and their short residence time in the nasal cavity, the ufasomes were incorporated into mucoadhesive hydrogels that were lyophilized into unit dosage forms for accurate dosing. Scanning electron micrographs of the lyophilized gel revealed that the included ufasomes were intact, non-aggregating and maintained their spherical morphology. Rheological characterization of reconstituted ufasomal lyophilized gel ensured ease of application. Furthermore, the gel induced minor histopathological alterations in sheeps' nasal mucosa. Ex-vivo confocal laser imaging confirmed the ability of ufasomes to penetrate deep through nasal mucosa layers. The results highlighted in the current work confirm the feasibility of using CN-loaded ufasomal gels for intranasal drug delivery.