Journal ArticleDOI
Molecular mobility-based estimation of the crystallization rates of amorphous nifedipine and phenobarbital in poly(vinylpyrrolidone) solid dispersions.
TLDR
The overall crystallization rates and mean relaxation times of amorphous nifedipine and phenobarbital in the presence of poly(vinylpyrrolidone) (PVP) were determined at various temperatures to gain further insight into the effect of molecular mobility on the crystallization rate of areorphous drugs and the possibility of predicting stability from their molecular mobility.About:
This article is published in Journal of Pharmaceutical Sciences.The article was published on 2004-02-01. It has received 151 citations till now. The article focuses on the topics: Amorphous solid & Crystallization.read more
Citations
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Journal ArticleDOI
Evaluation of amorphous solid dispersion properties using thermal analysis techniques.
Jared A. Baird,Lynne S. Taylor +1 more
TL;DR: Although differential scanning calorimetry is the most widely used thermal analytical technique applied to the characterization of amorphous solid dispersions, there are many established and emerging techniques which have been shown to provide useful information.
Journal ArticleDOI
Role of Thermodynamic, Molecular, and Kinetic Factors in Crystallization from the Amorphous State
Chandan Bhugra,Michael J. Pikal +1 more
TL;DR: An increased understanding of the relative contributions of molecular mobility and processing conditions are vital to increased usage of the amorphous state in solid oral dosage forms.
Journal ArticleDOI
Amorphous drug delivery systems: molecular aspects, design, and performance.
TL;DR: The various thermodynamic phenomenon such as glass transition, fragility, molecular mobility, devitrification kinetics, and molecular-level chemical interactions that contribute to the ease of formation, the solubility advantage, and the stability of amorphous drugs are discussed.
Journal ArticleDOI
Local mobility in amorphous pharmaceuticals—characterization and implications on stability
TL;DR: The coupling model, which correlated the local motions with global mobility, has been discussed in order to emphasize the potential impact of local mobility on amorphous phase stability and the Johari-Goldstein relaxations are highlighted.
Journal ArticleDOI
Solubilities of crystalline drugs in polymers: an improved analytical method and comparison of solubilities of indomethacin and nifedipine in PVP, PVP/VA, and PVAc.
TL;DR: The new annealing method yields more accurate data than the previous scanning method when solubility equilibrium is slow to achieve, and in practice, these two methods can be combined for efficiency.
References
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Journal ArticleDOI
Characteristics and Significance of the Amorphous State in Pharmaceutical Systems
Bruno C. Hancock,George Zografi +1 more
TL;DR: The amorphous state is critical in determining the solid-state physical and chemical properties of many pharmaceutical dosage forms and some of the most common methods that can be used to measure them are described.
Journal ArticleDOI
Spectroscopic characterization of interactions between PVP and indomethacin in amorphous molecular dispersions.
Lynne S. Taylor,George Zografi +1 more
TL;DR: A comparison of the carbonyl stretching region of γ indomethacin, known to form carboxylic acid dimers, with that of amorphous indometHacin indicated that the amorphously phase exists predominantly as dimers.
Journal ArticleDOI
Physical properties of solid molecular dispersions of indomethacin with poly(vinylpyrrolidone) and poly(vinylpyrrolidone-co-vinyl-acetate) in relation to indomethacin crystallization.
TL;DR: The major basis for crystal inhibition of indomethacin at 30°C at the 5% w/w polymer level in molecular dispersions is not related to polymer molecular weight and to the glass transition temperature, and is more likely related to the ability to hydrogen bond with indometHacin and to inhibit the formation of carboxylic acid dimers that are required for nucleation and growth to the γ crystal form of indometrichacIn.
Journal ArticleDOI
Significance of controlling crystallization mechanisms and kinetics in pharmaceutical systems
TL;DR: The illusion of process control is motivated by a crystallization process that yields the desired productssolid phase modification, shape, or size distributions by the robust analytical methods used for solid state characterization.
Journal ArticleDOI
Effects of annealing and prior history on enthalpy relaxation in glassy polymers. 6. Adam-Gibbs formulation of nonlinearity
TL;DR: Les relations entre les parametres d'Adam Gibbs decrivant les relaxations a l'etat vitreux, avec la variation du comportement des liquides au-dessus de Tg, suggerent que la non-linearite des relaxations de l'ETat vitréux and de la transition vitreuse, est une extension directe de la relaxation lineaire au dessus of Tg as mentioned in this paper.
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Characteristics and Significance of the Amorphous State in Pharmaceutical Systems
Bruno C. Hancock,George Zografi +1 more