Well-plate freeze-drying: a high throughput platform for screening of physical properties of freeze-dried formulations.

CONTEXT: Freeze-drying in presence of excipients is a common practice to stabilize biomacromolecular formulations. The composition of this formulation is known to affect the quality of the final product. OBJECTIVE: The aim of this study was to evaluate freeze-drying in well-plates as a high throughput platform for formulation screening of freeze-dried products. METHODS: Model formulations consisting of mannitol, sucrose and bovine serum albumin were freeze-dried in brass well plates, plastic well plates and vials. Physical properties investigated were solid form, residual moisture, cake collapse and reconstitution time. RESULTS: Samples freeze-dried in well-plates had an acceptable visual cake appearance. Solid form analysis by high throughput X-ray powder diffraction indicated comparable polymorphic outcome independent of the container. The expected increase in moisture level due to increasing amount of amorphous matter in the samples was observed in both vials and well plates. Cake collapse was found to be representative in well plates and could be effectively quantified using image analysis. Reconstitution time was also found to be equal in all three platforms. Finally no significant edge effect was found for any of the quality attributes analyzed. CONCLUSION: Freeze-drying in well-plates was found to be a suitable and representative high throughput platform for formulation screening.

Near-infrared imaging for high-throughput screening of moisture induced changes in freeze-dried formulations.

Evaluation of freeze-dried biopharmaceutical formulations requires careful analysis of multiple quality attributes. The aim of this study was to evaluate the use of near-infrared (NIR) imaging for fast analysis of water content and related physical properties in freeze-dried formulations. Model formulations were freeze-dried in well plates. Samples were imaged with a NIR hyperspectral camera after freeze-drying and upon storage. On the basis of Karl Fischer titration reference values, a univariate quantification model was constructed and used to visualize the distribution of water within freeze-dried samples. Differences observed between samples stored at 11% and 43% relative humidity (RH) were found to be related to the amount of amorphous component in the sample. When stored at 43% RH, the moisture content in samples with high sucrose content increased within 2 days and some degree of localized drying was observed within the samples after 3 days of storage. Further investigations with X-ray powder diffraction confirmed this local drying to be related to crystallization of sucrose. The combination of fast analysis of water content and spatial solid-state information makes NIR imaging a powerful tool for formulation development of freeze-dried samples.

Formation of mannitol hemihydrate in freeze-dried protein formulations--a design of experiment approach.

Since the discovery of mannitol hemihydrate, this form of mannitol has been seen as potentially negative with regard to the stability of pharmaceutical formulations. The formation of mannitol hemihydrate is reported in several case studies; however, no systematic investigation has been performed so far. In this study, design of experiments was applied for response surface modelling of mannitol hemihydrate formation. The formulation parameters investigated in a composite face-centred design were the overall solid content, protein concentration, protein type and the ratio between mannitol and sucrose. Additionally, annealing as process parameter was included in a full factorial mixed design. For two proteins, models with a high goodness of fit (R(2): 0.82 and 0.93) and goodness of prediction (Q(2): 0.78 and 0.89) were achieved. Inclusion of the process parameter annealing resulted in models of similar quality. The successful application of design of experiments showed that the most prominent factors enhancing the formation of hemihydrate were a high protein concentration, low relative mannitol content and annealing at -20°C.

Fuzzy Logic-based expert system for evaluating cake quality of freeze-dried formulations.

Freeze-drying of peptide and protein-based pharmaceuticals is an increasingly important field of research. The diverse nature of these compounds, limited understanding of excipient functionality, and difficult-to-analyze quality attributes together with the increasing importance of the biosimilarity concept complicate the development phase of safe and cost-effective drug products. To streamline the development phase and to make high-throughput formulation screening possible, efficient solutions for analyzing critical quality attributes such as cake quality with minimal material consumption are needed. The aim of this study was to develop a fuzzy logic system based on image analysis (IA) for analyzing cake quality. Freeze-dried samples with different visual quality attributes were prepared in well plates. Imaging solutions together with image analytical routines were developed for extracting critical visual features such as the degree of cake collapse, glassiness, and color uniformity. On the basis of the IA outputs, a fuzzy logic system for analysis of these freeze-dried cakes was constructed. After this development phase, the system was tested with a new screening well plate. The developed fuzzy logic-based system was found to give comparable quality scores with visual evaluation, making high-throughput classification of cake quality possible.

Detecting phase separation of freeze-dried binary amorphous systems using pair-wise distribution function and multivariate data analysis.

The purpose of this study is to investigate the use of multivariate data analysis for powder X-ray diffraction-pair-wise distribution function (PXRD-PDF) data to detect phase separation in freeze-dried binary amorphous systems. Polymer-polymer and polymer-sugar binary systems at various ratios were freeze-dried. All samples were analyzed by PXRD, transformed to PDF and analyzed by principal component analysis (PCA). These results were validated by differential scanning calorimetry (DSC) through characterization of glass transition of the maximally freeze-concentrate solute (Tg'). Analysis of PXRD-PDF data using PCA provides a more clear 'miscible' or 'phase separated' interpretation through the distribution pattern of samples on a score plot presentation compared to residual plot method. In a phase separated system, samples were found to be evenly distributed around the theoretical PDF profile. For systems that were miscible, a clear deviation of samples away from the theoretical PDF profile was observed. Moreover, PCA analysis allows simultaneous analysis of replicate samples. Comparatively, the phase behavior analysis from PXRD-PDF-PCA method was in agreement with the DSC results. Overall, the combined PXRD-PDF-PCA approach improves the clarity of the PXRD-PDF results and can be used as an alternative explorative data analytical tool in detecting phase separation in freeze-dried binary amorphous systems.