title: Glass transition temperature of glucose, sucrose, and trehalose: an experimental and in silico study.
abstract: Isothermal-isobaric molecular dynamics simulations are used to calculate the specific volume of models of different amorphous carbohydrates (glucose, sucrose, and trehalose) as a function of temperature. Plots of specific volume vs temperature exhibit a characteristic change in slope when the amorphous systems change from the glassy to the rubbery state. The intersection of the regression lines of data below (glassy state) and above (rubbery state) the change in slope provides the glass transition temperature (T(g)). These predicted glass transition temperatures are compared to experimental T(g) values as obtained from differential scanning calorimetry measurements. As expected, the predicted values are systematically higher than the experimental ones (about 12-34 K) as the cooling rates of the modeling methods are about a factor of 10(12) faster. Nevertheless, the calculated trend of T(g) values agrees exactly with the experimental trend: T(g)(glucose) < T(g)(sucrose) < T(g)(trehalose). Furthermore, the relative differences between the glass transition temperatures were also computed precisely, implying that atomistic molecular dynamics simulations can reproduce trends of T(g) values in amorphous carbohydrates with high quality.
authors.affiliation: The Pfizer Institute for Pharmaceutical Materials Science, Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Simperler
authors.forename: Andreas
authors.initials: A
authors.lastname: Kornherr
authors.forename: Reenu
authors.initials: R
authors.lastname: Chopra
authors.forename: P Arnaud
authors.initials: PA
authors.lastname: Bonnet
authors.forename: William
authors.initials: W
authors.lastname: Jones
authors.forename: W D Samuel
authors.initials: WD
authors.lastname: Motherwell
authors.forename: Gerhard
authors.initials: G
authors.lastname: Zifferer
mesh_terms: D001703:Biophysics / Q000379:methods; D002236:Carbohydrate Conformation; D002241:Carbohydrates / Q000737:chemistry*; D002627:Chemistry, Physical / Q000379:methods*; D005898:Glass; D005947:Glucose / Q000737:chemistry*; D008958:Models, Molecular; D008962:Models, Theoretical; D008968:Molecular Conformation; D012044:Regression Analysis; D013395:Sucrose / Q000737:chemistry*; D044366:Transition Temperature; D014199:Trehalose / Q000737:chemistry*
chemical_list: D002241:Carbohydrates; D013395:Sucrose; D014199:Trehalose; D005947:Glucose