The Experts below are selected from a list of 1794 Experts worldwide ranked by ideXlab platform
Michael J Hageman - One of the best experts on this subject based on the ideXlab platform.
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effects of Bovine Somatotropin rbst concentration at different moisture levels on the physical stability of sucrose in freeze dried rbst sucrose mixtures
Journal of Pharmaceutical Sciences, 1997Co-Authors: Jeannemarie E Sarciaux, Michael J HagemanAbstract:The inherent instability of many proteins during freeze-drying and storage necessitates the addition of excipients to protect the proteins. It is emphasized in the literature that lyophilized sugar/protein composites should be stored at temperatures below their glass transition temperature (T(g)) to prevent crystallization of excipients. The influence of Bovine Somatotropin (rbSt) concentration on inhibition of sucrose crystallization at different relative humidities (RH) was of interest. Thermally modulated differential scanning calorimetry (MDSC) was used to measure T(g) and sucrose crystallization temperatures (T(c)) of the composites. Sorption isotherms of the various sucrose/rbSt mixtures were determined gravimetrically with a controlled atmosphere microbalance (CAM) and verified by Karl Fischer analysis of selected samples. The CAM was also used to determine lag times and sucrose crystal growth rates by monitoring weight losses resulting from water liberation upon crystallization of sucrose at 23 degrees C. Results obtained by MDSC indicate that the T(c) increased linearly from approximately 110 degrees C for pure sucrose to approximately 140 degrees C with 20% rbSt at very low water content ( or = 30% rbSt in nonisothermal conditions. Plasticization by water decreased both T(g) and T(c) quite similarly but didn't impact the noted effect of protein on T(c). Induction time for sucrose crystallization (i.e. nucleation) at approximately 45% RH (23 degrees C) increased almost 10-fold by addition of 10% rbSt, whereas rates of water loss due to crystallization decreased by no more than 2-3-fold. The overall results strongly indicate that formulations of higher protein concentration will be more resistant to sucrose crystallization and thus more robust when transiently exposed to storage temperatures above their T(g).
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effects of Bovine Somatotropin rbst concentration at different moisture levels on the physical stability of sucrose in freeze dried rbst sucrose mixtures
Journal of Pharmaceutical Sciences, 1997Co-Authors: Jeannemarie E Sarciaux, Michael J HagemanAbstract:The inherent instability of many proteins during freeze-drying and storage necessitates the addition of excipients to protect the proteins. It is emphasized in the literature that lyophilized sugar/protein composites should be stored at temperatures below their glass transition temperature (Tg) to prevent crystallization of excipients. The influence of Bovine Somatotropin (rbSt) concentration on inhibition of sucrose crystallization at different relative humidities (RH) was of interest. Thermally modulated differential scanning calorimetry (MDSC) was used to measure Tg and sucrose crystallization temperatures (Tc) of the composites. Sorption isotherms of the various sucrose/rbSt mixtures were determined gravimetrically with a controlled atmosphere microbalance (CAM) and verified by Karl Fischer analysis of selected samples. The CAM was also used to determine lag times and sucrose crystal growth rates by monitoring weight losses resulting from water liberation upon crystallization of sucrose at 23 °C. Results obtained by MDSC indicate that the Tc increased linearly from ∼110 °C for pure sucrose to ∼140 °C with 20% rbSt at very low water content (< 0.1%). Similarly, at 22% RH (4.4% H2O), Tc increased from ∼70 °C to 120 °C. In neither case was Tg impacted significantly by increasing protein from 0 to 20%. No Tc could be noted for samples with ≥30% rbSt in nonisothermal conditions. Plasticization by water decreased both Tg and Tc quite similarly but did'nt impact the noted effect of protein on Tc. Induction time for sucrose crystallization (i.e. nucleation) at ∼45% RH (23 °C) increased almost 10-fold by addition of 10% rbSt, whereas rates of water loss due to crystallization decreased by no more than 2–3-fold. The overall results strongly indicate that formulations of higher protein concentration will be more resistant to sucrose crystallization and thus more robust when transiently exposed to storage temperatures above their Tg.
Michel W F Nielen - One of the best experts on this subject based on the ideXlab platform.
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monolith immuno affinity enrichment liquid chromatography tandem mass spectrometry for quantitative protein analysis of recombinant Bovine Somatotropin in serum
Analytical and Bioanalytical Chemistry, 2015Co-Authors: Nathalie G E Smits, M H Blokland, Klaas L Wubs, Merel A Nessen, Leen Van Ginkel, Michel W F NielenAbstract:The use of recombinant Bovine Somatotropin (rbST) to enhance milk production is approved in several countries, but it is prohibited in the European Union. According to EU legislation, it is necessary to confirm positive screening results prior to enforcement. Although adequate screening assays are available nowadays, development of liquid chromatography tandem mass spectrometry (LC-MS/MS) confirmatory methods to detect low levels of rbST is still a challenge. Here, we present a novel approach using immuno-affinity enrichment on monolithic micro-columns in combination with state-of-the-art ultra-high pressure LC-MS/MS (UHPLC-MS/MS) detection. The developed approach enables detection and confirmation of rbST in serum at a decision limit (CCα) concentration of 0.8 ng mL−1. Furthermore, the method is easy to handle, robust and reproducible. We successfully applied the confirmatory method to serum samples from rbST treated cows that were found suspect after immunoassay-based screening. The use of rbST could be confirmed over 1 week after treatment, and the developed method demonstrated the sensitivity needed for effective control.
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Smartphone with fluorescence microscope attachment, detection setup and microarray image.
2015Co-Authors: Susann K. J. Ludwig, Christian Tokarski, Stefan N. Lang, Leendert A. Van Ginkel, Hongying Zhu, Aydogan Ozcan, Michel W F NielenAbstract:(A) Photograph of the 3D-printed microscopic imaging attachment on the smartphone that was used for analysis. (B) Setup of the smartphone biomarker detection platform. (C) Exemplary microarray image obtained using the smartphone fluorescence microscope. (D) Microarray layout for spotting of four different proteins: recombinant Bovine Somatotropin (rbST) for detection of the biomarker anti-rbST antibody (α-rbST, blue), anti-insulin-like growth factor-1 (IGF-1) antibody (spotted in two concentrations: 100 μg mL-1 and 250 μg mL-1) for detection of the biomarker IGF-1 (IGF-1 100, yellow; IGF-1 250, orange), ovalbumin as a negative control (N, grey) and sheep IgG as positive control (P, green).
Jeannemarie E Sarciaux - One of the best experts on this subject based on the ideXlab platform.
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effects of Bovine Somatotropin rbst concentration at different moisture levels on the physical stability of sucrose in freeze dried rbst sucrose mixtures
Journal of Pharmaceutical Sciences, 1997Co-Authors: Jeannemarie E Sarciaux, Michael J HagemanAbstract:The inherent instability of many proteins during freeze-drying and storage necessitates the addition of excipients to protect the proteins. It is emphasized in the literature that lyophilized sugar/protein composites should be stored at temperatures below their glass transition temperature (T(g)) to prevent crystallization of excipients. The influence of Bovine Somatotropin (rbSt) concentration on inhibition of sucrose crystallization at different relative humidities (RH) was of interest. Thermally modulated differential scanning calorimetry (MDSC) was used to measure T(g) and sucrose crystallization temperatures (T(c)) of the composites. Sorption isotherms of the various sucrose/rbSt mixtures were determined gravimetrically with a controlled atmosphere microbalance (CAM) and verified by Karl Fischer analysis of selected samples. The CAM was also used to determine lag times and sucrose crystal growth rates by monitoring weight losses resulting from water liberation upon crystallization of sucrose at 23 degrees C. Results obtained by MDSC indicate that the T(c) increased linearly from approximately 110 degrees C for pure sucrose to approximately 140 degrees C with 20% rbSt at very low water content ( or = 30% rbSt in nonisothermal conditions. Plasticization by water decreased both T(g) and T(c) quite similarly but didn't impact the noted effect of protein on T(c). Induction time for sucrose crystallization (i.e. nucleation) at approximately 45% RH (23 degrees C) increased almost 10-fold by addition of 10% rbSt, whereas rates of water loss due to crystallization decreased by no more than 2-3-fold. The overall results strongly indicate that formulations of higher protein concentration will be more resistant to sucrose crystallization and thus more robust when transiently exposed to storage temperatures above their T(g).
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effects of Bovine Somatotropin rbst concentration at different moisture levels on the physical stability of sucrose in freeze dried rbst sucrose mixtures
Journal of Pharmaceutical Sciences, 1997Co-Authors: Jeannemarie E Sarciaux, Michael J HagemanAbstract:The inherent instability of many proteins during freeze-drying and storage necessitates the addition of excipients to protect the proteins. It is emphasized in the literature that lyophilized sugar/protein composites should be stored at temperatures below their glass transition temperature (Tg) to prevent crystallization of excipients. The influence of Bovine Somatotropin (rbSt) concentration on inhibition of sucrose crystallization at different relative humidities (RH) was of interest. Thermally modulated differential scanning calorimetry (MDSC) was used to measure Tg and sucrose crystallization temperatures (Tc) of the composites. Sorption isotherms of the various sucrose/rbSt mixtures were determined gravimetrically with a controlled atmosphere microbalance (CAM) and verified by Karl Fischer analysis of selected samples. The CAM was also used to determine lag times and sucrose crystal growth rates by monitoring weight losses resulting from water liberation upon crystallization of sucrose at 23 °C. Results obtained by MDSC indicate that the Tc increased linearly from ∼110 °C for pure sucrose to ∼140 °C with 20% rbSt at very low water content (< 0.1%). Similarly, at 22% RH (4.4% H2O), Tc increased from ∼70 °C to 120 °C. In neither case was Tg impacted significantly by increasing protein from 0 to 20%. No Tc could be noted for samples with ≥30% rbSt in nonisothermal conditions. Plasticization by water decreased both Tg and Tc quite similarly but did'nt impact the noted effect of protein on Tc. Induction time for sucrose crystallization (i.e. nucleation) at ∼45% RH (23 °C) increased almost 10-fold by addition of 10% rbSt, whereas rates of water loss due to crystallization decreased by no more than 2–3-fold. The overall results strongly indicate that formulations of higher protein concentration will be more resistant to sucrose crystallization and thus more robust when transiently exposed to storage temperatures above their Tg.
Nathalie G E Smits - One of the best experts on this subject based on the ideXlab platform.
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monolith immuno affinity enrichment liquid chromatography tandem mass spectrometry for quantitative protein analysis of recombinant Bovine Somatotropin in serum
Analytical and Bioanalytical Chemistry, 2015Co-Authors: Nathalie G E Smits, M H Blokland, Klaas L Wubs, Merel A Nessen, Leen Van Ginkel, Michel W F NielenAbstract:The use of recombinant Bovine Somatotropin (rbST) to enhance milk production is approved in several countries, but it is prohibited in the European Union. According to EU legislation, it is necessary to confirm positive screening results prior to enforcement. Although adequate screening assays are available nowadays, development of liquid chromatography tandem mass spectrometry (LC-MS/MS) confirmatory methods to detect low levels of rbST is still a challenge. Here, we present a novel approach using immuno-affinity enrichment on monolithic micro-columns in combination with state-of-the-art ultra-high pressure LC-MS/MS (UHPLC-MS/MS) detection. The developed approach enables detection and confirmation of rbST in serum at a decision limit (CCα) concentration of 0.8 ng mL−1. Furthermore, the method is easy to handle, robust and reproducible. We successfully applied the confirmatory method to serum samples from rbST treated cows that were found suspect after immunoassay-based screening. The use of rbST could be confirmed over 1 week after treatment, and the developed method demonstrated the sensitivity needed for effective control.
M H Blokland - One of the best experts on this subject based on the ideXlab platform.
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monolith immuno affinity enrichment liquid chromatography tandem mass spectrometry for quantitative protein analysis of recombinant Bovine Somatotropin in serum
Analytical and Bioanalytical Chemistry, 2015Co-Authors: Nathalie G E Smits, M H Blokland, Klaas L Wubs, Merel A Nessen, Leen Van Ginkel, Michel W F NielenAbstract:The use of recombinant Bovine Somatotropin (rbST) to enhance milk production is approved in several countries, but it is prohibited in the European Union. According to EU legislation, it is necessary to confirm positive screening results prior to enforcement. Although adequate screening assays are available nowadays, development of liquid chromatography tandem mass spectrometry (LC-MS/MS) confirmatory methods to detect low levels of rbST is still a challenge. Here, we present a novel approach using immuno-affinity enrichment on monolithic micro-columns in combination with state-of-the-art ultra-high pressure LC-MS/MS (UHPLC-MS/MS) detection. The developed approach enables detection and confirmation of rbST in serum at a decision limit (CCα) concentration of 0.8 ng mL−1. Furthermore, the method is easy to handle, robust and reproducible. We successfully applied the confirmatory method to serum samples from rbST treated cows that were found suspect after immunoassay-based screening. The use of rbST could be confirmed over 1 week after treatment, and the developed method demonstrated the sensitivity needed for effective control.