Optimization of continuous spin-freeze-drying: The role of spin-freezing on quality attributes and drying efficiency of a model peptide formulation.

Continuous spin-freeze-drying is an innovative pharmaceutical manufacturing approach offering real-time monitoring and control at the individual vial level, unlike conventional batch lyophilization. A central feature of this technology is spin-freezing, which involves rapidly spinning liquid-filled vials under a precisely controlled cold gas flow, resulting in a thin, uniform frozen product layer. Using a model peptide formulation, we investigated the impact of different cooling and crystallization rates on quality attributes (QA) and primary drying duration.

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

Spin freeze-drying, as a part of a continuous freeze-drying technology, is associated with a much higher drying rate and a higher level of process control in comparison with batch freeze-drying. However, the impact of the spin freezing rate on the dried product layer characteristics is not well understood at present. This research focuses on the relation between spin-freezing and pore size, pore shape, dried product mass transfer resistance and solid state of the dried product layer.

Development and Application of a Mechanistic Cooling and Freezing Model of the Spin Freezing Step within the Framework of Continuous Freeze-Drying.

During the spin freezing step of a recently developed continuous spin freeze-drying technology, glass vials are rapidly spun along their longitudinal axis. The aqueous drug formulation subsequently spreads over the inner vial wall, while a cold gas flow is used for cooling and freezing the product. In this work, a mechanistic model was developed describing the energy transfer during each phase of spin freezing in order to predict the vial and product temperature change over time.

Lyophilization of NOTA-sdAbs: First step towards a cold diagnostic kit for Ga-labeling.

Unlabelled: Lyophilization is commonly used in the production of pharmaceutical compounds to increase the stability of the Active Pharmaceutical Ingredient (API) by removing solvents. This study investigates the possibility to lyophilize an anti-HER2 and an anti-MMR single-domain antibody fragment (sdAb)-based precursor as a first step in the development of a diagnostic kit for PET imaging.

Methods: NOTA-sdAb precursors have been lyophilized with the following formulation: 100 µg NOTA-sdAb in 0.

Dual chamber cartridges in a continuous pharmaceutical freeze-drying concept: Determination of the optimal dynamic infrared heater temperature during primary drying.

The applicability of DCCs in a continuous freeze-drying concept based on spin freezing and infrared heating was evaluated. Maximum applicable filling volume was evaluated. Secondly the mechanistic model for the determination of the optimal dynamic infrared heater temperature during primary drying of regular vials during continuous freeze-drying was adapted and validated for DCCs.

The generation and use of recombinant extracellular vesicles as biological reference material.

Recent years have seen an increase of extracellular vesicle (EV) research geared towards biological understanding, diagnostics and therapy. However, EV data interpretation remains challenging owing to complexity of biofluids and technical variation introduced during sample preparation and analysis. To understand and mitigate these limitations, we generated trackable recombinant EV (rEV) as a biological reference material.

Thermal Imaging as a Noncontact Inline Process Analytical Tool for Product Temperature Monitoring during Continuous Freeze-Drying of Unit Doses.

Freeze-drying is a well-established technique to improve the stability of biopharmaceuticals which are unstable in aqueous solution. To obtain an elegant dried product appearance, the temperature at the moving sublimation interface T should be kept below the critical product temperature T during primary drying. The static temperature sensors applied in batch freeze-drying provide unreliable T data due to their invasive character.

Vacuum Induced Surface Freezing as an effective method for improved inter- and intra-vial product homogeneity.

The stochastic nature of nucleation makes it difficult to control batch homogeneity in conventional freezing, and this lack of control is in contrast with the current emphasis on Quality by Design. Among the techniques which have been developed to overcome this problem, Vacuum Induced Surface Freezing is probably the most promising for application in manufacturing, because it does not require additional equipment and can be scaled-up more easily than other proposed approaches. In this work, we summarize the impact of Vacuum Induced Surface Freezing on product morphology, and the efficiency of the subsequent drying steps as well.

Potential of Near-Infrared Chemical Imaging as Process Analytical Technology Tool for Continuous Freeze-Drying.

Near-infrared chemical imaging (NIR-CI) is an emerging tool for process monitoring because it combines the chemical selectivity of vibrational spectroscopy with spatial information. Whereas traditional near-infrared spectroscopy is an attractive technique for water content determination and solid-state investigation of lyophilized products, chemical imaging opens up possibilities for assessing the homogeneity of these critical quality attributes (CQAs) throughout the entire product. In this contribution, we aim to evaluate NIR-CI as a process analytical technology (PAT) tool for at-line inspection of continuously freeze-dried pharmaceutical unit doses based on spin freezing.

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 relevance of shear, sedimentation and diffusion during spin freezing, as potential first step of a continuous freeze-drying process for unit doses.

Recently, a continuous freeze-drying process for the production of unit doses was presented and evaluated. In this concept, the freezing step is modified compared to traditional batch freeze-drying, as glass vials filled with a liquid formulation, are rotated around their longitudinal axis while cooled and frozen with a cold, sterile and inert gas (i.e.

Polymorphism of Indomethacin in Semicrystalline Dispersions: Formation, Transformation, and Segregation.

The crystallization of metastable crystal polymorphs in polymer matrices has been extensively reported in literature as a possible approach to enhance the solubility of poorly water-soluble drug compounds, yet no clarification of the mechanism of the polymorph formation has been proposed. The current work aims to elucidate the polymorphism behavior of the model compound indomethacin as well as the mechanism of polymorph selection of drugs in semicrystalline systems. Indomethacin crystallized as either the α- or τ-form, a new metastable form, or a mixture of the two polymorphs in dispersions containing different drug loadings in polyethylene glycol, poloxamer, or Gelucire as the result of the variation in the mobility of drug molecules.

Global Sensitivity Analysis as Good Modelling Practices tool for the identification of the most influential process parameters of the primary drying step during freeze-drying.

Pharmaceutical batch freeze-drying is commonly used to improve the stability of biological therapeutics. The primary drying step is regulated by the dynamic settings of the adaptable process variables, shelf temperature T and chamber pressure P. Mechanistic modelling of the primary drying step leads to the optimal dynamic combination of these adaptable process variables in function of time.

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 T and chamber pressure P. Mechanistic modelling of the primary drying step allows the computation of the optimal combination of T and P in function of the primary drying time.

Modelling the primary drying step for the determination of the optimal dynamic heating pad temperature in a continuous pharmaceutical freeze-drying process for unit doses.

In the pharmaceutical industry, traditional freeze-drying of unit doses is a batch-wise process associated with many disadvantages. To overcome these disadvantages and to guarantee a uniform product quality and high process efficiency, a continuous freeze-drying process is developed and evaluated. The main differences between the proposed continuous freeze-drying process and traditional freeze-drying can be found firstly in the freezing step during which the vials are rotated around their longitudinal axis (spin freezing), and secondly in the drying step during which the energy for sublimation and desorption is provided through the vial wall by conduction via an electrical heating pad.

Formulation Optimization of Freeze-Dried Long-Circulating Liposomes and In-Line Monitoring of the Freeze-Drying Process Using an NIR Spectroscopy Tool.

The effect of lyoprotectant type and concentration on the stability of freeze-dried prednisolone sodium phosphate-loaded long-circulating liposomes was investigated. Trehalose at a 5:1 carbohydrate to lipid molar ratio proved to be superior in maintaining the structural integrity and the permeability properties of the liposome bilayers, assuring the desired characteristics of the final product: a cake with a porous structure and easy to reconstitute, a similar size to the liposomes before freeze-drying, a high percent of encapsulated drug, and a low residual moisture content. Further on, the study demonstrated the possibility of near-infrared spectroscopy to provide valuable insights for detecting critical changes in acyl chain packing of the liposome bilayer.

Mechanistic modelling of infrared mediated energy transfer during the primary drying step of a continuous freeze-drying process.

Conventional pharmaceutical freeze-drying is an inefficient and expensive batch-wise process, associated with several disadvantages leading to an uncontrolled end product variability. The proposed continuous alternative, based on spinning the vials during freezing and on optimal energy supply during drying, strongly increases process efficiency and improves product quality (uniformity). The heat transfer during continuous drying of the spin frozen vials is provided via non-contact infrared (IR) radiation.

Noncontact Infrared-Mediated Heat Transfer During Continuous Freeze-Drying of Unit Doses.

Recently, an innovative continuous freeze-drying concept for unit doses was proposed, based on spinning the vials during freezing. An efficient heat transfer during drying is essential to continuously process these spin frozen vials. Therefore, the applicability of noncontact infrared (IR) radiation was examined.

Impact of vacuum-induced surface freezing on inter- and intra-vial heterogeneity.

This paper aimed to study the impact of freezing on both within-batch (inter-vial) and within-product (intra-vial) heterogeneity. This analysis has been carried out using two freezing protocols, the conventional shelf-ramped method and the Vacuum Induced Surface Freezing, and placebo formulations containing both crystallizing (mannitol) and amorphous (lactose and sucrose) excipients. The freezing conditions (i.

Uncertainty analysis as essential step in the establishment of the dynamic Design Space of primary drying during freeze-drying.

Large molecules, such as biopharmaceuticals, are considered the key driver of growth for the pharmaceutical industry. Freeze-drying is the preferred way to stabilise these products when needed. However, it is an expensive, inefficient, time- and energy-consuming process.

Comparison of metoprolol tartrate multiple-unit lipid matrix systems produced by different technologies.

The aim of this study was to develop, evaluate and compare extended release mini-matrices based on metoprolol tartrate (MPT) and either glyceryl behenate (GB) or glyceryl palmitostearate (GPS). Mini-matrices were produced by three different techniques: hot melt extrusion, compression of melt granulates and prilling. Hot-melt extrusion and compression of granules obtained from melted material proved to be reliable, robust and reproducible techniques with aim of obtaining extended release matrices.

In-line near infrared spectroscopy during freeze-drying as a tool to measure efficiency of hydrogen bond formation between protein and sugar, predictive of protein storage stability.

Sugars are often used as stabilizers of protein formulations during freeze-drying. However, not all sugars are equally suitable for this purpose. Using in-line near-infrared spectroscopy during freeze-drying, it is shown here that hydrogen bond formation during freeze-drying, under secondary drying conditions in particular, can be related to the preservation of the functionality and structure of proteins during storage.