Glass-Transition Temperature of the β-Relaxation as the Major Predictive Parameter for Recrystallization of Neat Amorphous Drugs.
The journal of physical chemistry. B
American Chemical Society
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Kissi, E. O., Grohganz, H., Löbmann, K., Ruggiero, M., Zeitler, A., & Rades, T. (2018). Glass-Transition Temperature of the β-Relaxation as the Major Predictive Parameter for Recrystallization of Neat Amorphous Drugs.. The journal of physical chemistry. B, 122 (10), 2803-2808. https://doi.org/10.1021/acs.jpcb.7b10105
Recrystallization of amorphous drugs is currently limiting the simple approach to improve solubility and bioavailability of poorly water-soluble drugs by amorphization of a crystalline form of the drug. In view of this, molecular mobility, α-relaxation and β-relaxation processes with the associated transition temperatures Tgα and Tgβ, was investigated using dynamic mechanical analysis (DMA). The correlation between the transition temperatures and the onset of recrystallization for nine amorphous drugs, stored at dry conditions at a temperature of 296 K, was determined. From the results obtained, Tgα does not correlate with the onset of recrystallization at the experimental storage conditions. However, a clear correlation between Tgβ and the onset of recrystallization was observed. It is shown that at storage temperature below Tgβ, amorphous nifedipine retains its amorphous form. Based on the correlation, an empirical correlation is proposed for predicting the onset of recrystallization for drugs stored at 0% RH and 296 K.
Glass, Pharmaceutical Preparations, Crystallization, Solubility, Transition Temperature, Mechanical Phenomena
External DOI: https://doi.org/10.1021/acs.jpcb.7b10105
This record's URL: https://www.repository.cam.ac.uk/handle/1810/275627