importance of glass transition temperature

Since the formulations exist in glassy state during their shelf-life, accelerated stability data generated in the glassy state (40 degrees C) is perhaps a better predictor of the relative stability of formulations than the data generated at a higher temperature (60 degrees C) where one formulation is in the glassy state while the other is near or above its Tg. 1994 Apr;12(4):114-7. doi: 10.1016/0167-7799(94)90087-6. The first is to provide a polymer system with a high T(g) and low CTE. Aggregation of protein in the solid state was monitored using size-exclusion chromatography.  |  -. By understanding the fundamental properties of T(g) and CTE, we can overcome the challenges and provide two polymers with very dissimilar properties that will perform in a demanding thermal cycling environment. Cast Electrical and Mechanical Components, Maintenance, Restoration and Repair Materials. NLM Clipboard, Search History, and several other advanced features are temporarily unavailable. As presented in the TMA graph in figure 1, the T(g) is the temperature at which the polymer transitions from the glassy, rigid state into the flexible, rubbery state. Epub 2013 Apr 2. This challenge has been addressed successfully in the industry by one of two ways. Ribbon Cast™ Polyurethane System for Roller Manufacturing, Triathane® Variable Hardness Polyurethane, UL® Recognized Epoxy and Urethane Products, Safety Considerations using Urethane Products, Casting Method for Cast Coil and Instrument Transformers, How to evaluate Epoxy or Urethane products, How to remove cured Epoxy or Polyurethane, Procedure for Vacuum / Pressure Casting Fine Wire Coils, 4 Reasons you have epoxy and polyurethane curing issues. In demanding electrical/electronic applications, thermosetting epoxies and polyurethanes may be used to bond components or hermetically seal the assemblies through a potting or casting process. Effects of molecular weight of polyvinylpyrrolidone on the glass transition and crystallization of co-lyophilized sucrose. 1.2.1 Glass Transition Temperature, Tg The glass transition temperature, often called T g (or “T sub g”), is an important property when considering polymers for a particular end-use. 1. A typical filled epoxy system may have a CTE in the range of 30-60 ppm below its T(g) and a CTE in the range of 120-180 ppm above its T(g). Importance of glass transition temperature in accelerated stability testing of amorphous solids: case study using a lyophilized aspirin formulation. Deformation behaviors of tolbutamide, hydroxypropyl-beta-cyclodextrin, and their dispersions. HHS A quantitative assessment of the significance of molecular mobility as a determinant for the stability of lyophilized insulin formulations. Developments in the formulation and delivery of spray dried vaccines. Observation of high-temperature macromolecular confinement in lyophilised protein formulations using terahertz spectroscopy. Please enable it to take advantage of the complete set of features! Suihko E, Poso A, Korhonen O, Gynther J, Ketolainen J, Paronen P. Pharm Res. As with melting though, the Tg is signified by a change in heat capacity. This system would have a T(g) higher than the upper most operating temperature of the device, and a filler loading as high as possible to provide the lowest possible CTE and lowest shrink. Yoshioka S, Miyazaki T, Aso Y, Kawanishi T. Pharm Res. NLM 2001 Mar;18(3):256-60. doi: 10.1023/a:1011082309058. Trends Biotechnol. -, J Pharm Sci. USA.gov. This site needs JavaScript to work properly. Canada. Effect of moisture on the stability of a lyophilized humanized monoclonal antibody formulation. HHS COVID-19 is an emerging, rapidly evolving situation. Temperature dependence of bimolecular reactions associated with molecular mobility in lyophilized formulations. iGC SEA can provide a fast and accurate determination of this property as well as its dependence on relative humidity. Epub 2007 Apr 3. Increase in the protein/sugar ratio was found to increase the Tgs of the formulations containing sucrose or trehalose, but to different degrees. Phone: (+1) 905.673.0510Toll free North America: 1.800.563.37696380 Viscount Road, Mississauga, ON L4V 1H3. The goal is to provide a system that closely mirrors the dimensional changes of the components in the assembly during a thermal cycle. Figure 1 courtesy: http://www.ami.ac.uk/courses/topics/0140_pl/. A glass transition temperature (Tg) is the temperature at which a polymer turns from a ductile material to a hard, brittle material.  |  As a result, this low stress polymer will not damage delicate components during thermal cycling. An example of this would be an epoxy system with a high loading of inorganic filler. © Copyright 2020 Crosslink Technology Inc. Why is the Glass Transition Temperature and CTE important? Get the latest public health information from CDC: https://www.coronavirus.gov. This system would have a T(g) below the lowest operating temperature of the device. Accelerated stability testing of bioproducts: attractions and pitfalls. Pharm Res. Please enable it to take advantage of the complete set of features! -, Science. Epub 2013 Jan 31. Conclusions: The glass transition temperature Tg is an important property for the characterisation of polymeric, food, pharmaceutical and many natural products. 2007 Sep;24(9):1660-7. doi: 10.1007/s11095-007-9296-2. Freeze drying of nanosuspensions, 2: the role of the critical formulation temperature on stability of drug nanosuspensions and its practical implication on process design. Beirowski J, Inghelbrecht S, Arien A, Gieseler H. J Pharm Sci. Early drug development predictions of glass-forming ability and physical stability of drugs. eCollection 2019 Dec. Snell JR, Kumar NSK, Suryanarayanan R, Randolph TW. Get the latest research from NIH: https://www.nih.gov/coronavirus.  |  2000 Aug;17(8):942-8. doi: 10.1023/a:1007523103979. Pharm Res. 2017 Oct 3;13(10):2364-2378. doi: 10.1080/21645515.2017.1356952. 1999 Mar 15;179(2):179-207. doi: 10.1016/s0378-5173(98)00338-x. This would provide a polymer system that remains flexible and rubbery throughout the entire operating temperature range of the device. Epub 2006 Sep 2.  |  Int J Pharm. Kanojia G, Have RT, Soema PC, Frijlink H, Amorij JP, Kersten G. Hum Vaccin Immunother. Glass transition temperatures were measured using DSC and dielectric relaxation spectroscopy. Methods: Epub 2005 Aug 3. Lin X, Hu Y, Liu L, Su L, Li N, Yu J, Tang B, Yang Z. Pharm Res. An example of this would be a low hardness shore A polyurethane system. National Center for Biotechnology Information, Unable to load your collection due to an error, Unable to load your delegates due to an error. This helps minimize the development of any stresses within the assembly. Eur J Pharm Sci. How important is Coefficient of Thermal Expansion (CTE) in selecting Epoxy or Urethane Compounds. Each polymer with an amorphous structure has its own unique glass transition temperature, which makes a given polymer … In Chemical Resistance of Thermoplastics, 2012. J Pharm Sci. Find NCBI SARS-CoV-2 literature, sequence, and clinical content: https://www.ncbi.nlm.nih.gov/sars-cov-2/. 2019 Dec 23;37(1):11. doi: 10.1007/s11095-019-2739-8. This damage may show up as stress cracks in or around components, or a loss of adhesion between components. Pharm Res. 1996 Mar;85(3):345-7 Purpose: Effect of water on the chemical stability of amorphous pharmaceuticals: I. J Pharm Sci. This site needs JavaScript to work properly. Pharm Res. When these assemblies thermal cycle in operation any mismatch in CTE, or change in CTE, can cause damage to the assembly. Epub 2011 May 23. Results: Purpose: The purpose of this study is to highlight the importance of knowing the glass transition temperature, Tg, of a lyophilized amorphous solid composed primarily of a sugar and a protein in the interpretation of accelerated stability data. An approach that has been successfully implemented in many industry applications. A marked change in CTE also takes place at this transition temperature. The glass transition temperature is lower than the melting point of its crystalline form, if it has one. Definition of Glass Transition Temperature: The glass transition temperature is the temperature at which an amorphous solid becomes soft upon heating or brittle upon cooling. Pharm Res. Int J Pharm. This paper describes the characterisation of  |  Int J Pharm X. 2020 Jan;109(1):284-292. doi: 10.1016/j.xphs.2019.05.005. Epub 2019 May 13. Usefulness of the Kohlrausch-Williams-Watts stretched exponential function to describe protein aggregation in lyophilized formulations and the temperature dependence near the glass transition temperature. Shmool TA, Woodhams PJ, Leutzsch M, Stephens AD, Gaimann MU, Mantle MD, Kaminski Schierle GS, van der Walle CF, Zeitler JA.

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