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Glass-Transition Temperature of the β-Relaxation as the Major Predictive Parameter for Recrystallization of Neat Amorphous Drugs.

Accepted version
Peer-reviewed

Type

Article

Change log

Authors

Löbmann, Korbinian 
Ruggiero, Michael T  ORCID logo  https://orcid.org/0000-0003-1848-2565

Abstract

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 under dry conditions at a temperature of 296 K, was determined. From the results obtained, Tgα does not correlate with the onset of recrystallization under 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. On the basis of the correlation, an empirical correlation is proposed for predicting the onset of recrystallization for drugs stored at 0% RH and 296 K.

Description

Keywords

Crystallization, Glass, Mechanical Phenomena, Pharmaceutical Preparations, Solubility, Transition Temperature

Journal Title

J Phys Chem B

Conference Name

Journal ISSN

1520-6106
1520-5207

Volume Title

122

Publisher

American Chemical Society (ACS)
Sponsorship
EPSRC (1198)