In-line monitoring of surfactant clearance in viral vaccine downstream processing.

PURPOSE: The goal of this study is to examine the suitability of in-line infrared measurements to monitor, in real-time, surfactant concentration in the viral vaccine drug substance during a 50KDa tangential flow filtration (TFF) process. METHODS: A ReactIR™ 702L instrument was used to gather spectra of process off-line samples and reference materials to assess the feasibility of monitoring surfactant concentration during a TFF process in real-time. Both univariate and multivariate models were used to evaluate the off-line sample data and were found to be in good agreement with surfactant concentration values obtained by HPLC. These results were used as justification for a real-time TFF experiment with live process material. RESULTS: Small scale ReactIR experiments with process material demonstrated that a multivariate model using the 1300 cm-1 to 1000 cm-1 spectral region can be used to predict surfactant concentrations between TFF exchanges 8 to 15. CONCLUSION: The results of this study demonstrated suitability of an in-line infrared measurement to monitor surfactant concentration in the viral vaccine drug substance between exchanges 8-15 of a 50 kDa tangential flow filtration process. The preliminary multivariate model used for this work can be further optimized for the in-line use at manufacturing scale.

PAT solutions to monitor adsorption of Tetanus Toxoid with aluminum adjuvants.

The focus of this study was to examine the small-scale adsorption process of Tetanus Toxoid (TT) as a model protein antigen to aluminum phosphate (AlPO4) and aluminum oxyhydroxide (AlOOH) adjuvants with real-time monitoring by in-line ReactIR™, ParticleTrack™ based on Focused Beam Reflectance Measurement (FBRM) and EasyViewer™ probes. The adsorption process of AlPO4 and AlOOH with TT using was monitored in the small-scale reactors. Conformational changes in TT were monitored using in-line infrared probe ReactIR, whereas particle formation associated with protein adsorption were measured by particle size, count, and imaging tools, such as ParticleTrack with FBRM and EasyViewer probes. ParticleTrack distribution results and kinetic measurements were also supported by observations made using EasyViewer. In addition to EasyMax, BioBLU reactor was also used for the adsorption experiments. ReactIR with ATR-Fiber probe was effectively able to monitor adsorption progress of TT to AlOOH and to AlPO4. ReactIR, EasyViewer, and ParticleTrack provided detailed mechanistic and kinetic information for reaction of TT with AlPO4 and AlOOH. These in-situ measurements revealed a possible multi-step process for TT to AlPO4 which may be an indication of antigen adsorption.

Aluminum Phosphate Vaccine Adjuvant: Analysis of Composition and Size Using Off-Line and In-Line Tools.

PURPOSE: Aluminum-based adjuvants including aluminum phosphate (AlPO4) are commonly used in many human vaccines to enhance immune response. The interaction between the antigen and adjuvant, including the physical adsorption of antigen, may play a role in vaccine immunogenicity and is a useful marker of vaccine product quality and consistency. Thus, it is important to study the physicochemical properties of AlPO4, such as particle size and chemical composition. Control of the vaccine adjuvant throughout the manufacturing process, including raw materials and the intermediate and final product stages, can be effectively achieved through monitoring of such key product attributes to help ensure product quality. METHODS: This study focuses on the compositional analysis of AlPO4 adjuvant at the intermediate and final manufacturing stages using the off-line methods Fourier-Transform Infrared (FTIR) and Raman spectroscopy, X-ray Photoelectron Spectroscopy (XPS), and the in-line method Attenuated Total Reflectance (ATR). Particle size distribution of AlPO4 was measured off-line using Laser diffraction (LD) and in-line using Focused Beam Reflectance Measurement (FBRM®). RESULTS: There was no observable difference in size distribution between the intermediate and final stage AlPO4 by off-line and in-line analysis, in both small- or large-scale production samples. Consistent peak shifts were observed in off-line and in-line infrared (IR) spectroscopy as well as off-line XPS for both small- and large-scale AlPO4 manufacturing runs. Additionally, IR spectroscopy and FBRM® for size distribution were used as in-line process analytical technology (PAT) to monitor reaction progress in real-time during small-scale AlPO4 manufacturing from raw materials. The small-scale adsorption process of a model protein antigen (Tetanus toxoid) to AlPO4 adjuvant was also monitored by in-line ReactIR probe. CONCLUSION: This study demonstrated that in-line PAT can be used to monitor particle size and chemical composition for the various stages of adjuvant manufacturing from raw materials through intermediate to final adjuvant product stage. Similar approaches can be utilized to help assess lot-to-lot consistency during adjuvant manufacturing and vaccine product development. Moreover, the use of in-line PAT is highly conductive to advanced manufacturing strategies such as real-time product release testing and automated processes of the future.

Assessment of hair and bone accumulation of beryllium by mice exposed to contaminated dusts.

This study looks at the accumulation of Be in the hair and bones of mice to understand both the use of hair as a bioindicator of exposure to Be and accumulation in bones as a means to evaluate the translocation of Be. We exposed two groups of mice (C3H/HeJ) to 250 microg m(-3) of two different particles sizes of Be metal (fine and intermediate; Be-F and Be-I) during 3 weeks of nose-only inhalation exposure. A control group was exposed to HEPA-filtered air. Mice were sacrificed either 1 or 3 weeks after the end of exposure. Mice were shaved and the bones were extracted. For washed hair, the results of mice sacrificed one week after the end of exposure were 8.3 + or - 1.4 microg kg(-1) hair for the control group, 114 + or - 42 microg kg(-1 )hair for the Be-I group, and 159 + or - 65 microg kg(-1) hair for the Be-F group. Results for Be-F mice sacrificed 3 weeks after the end of exposure showed an average Be concentration in washed hair of 419 + or - 100 microg kg(-1), thus suggesting that excretion of Be in hair increases with time. Be concentration in bones was 6 + or - 3 microg kg(-1) dry bone tissues for the control group, compared with 24 + or - 7 microg kg(-1) for Be-I and 34 + or - 6 or 43 + or - 8 microg kg(-1) for Be-F in mice sacrificed 1 or 3 weeks after the end of exposure. These results demonstrate the potential of using hair and bone as bioindicators of Be exposure.