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Fundamental aspects of solid dispersion technology for poorly soluble drugs.

Huang Y, Dai WG - Acta Pharm Sin B (2013)

Bottom Line: The solid dispersion has become an established solubilization technology for poorly water soluble drugs.Since a solid dispersion is basically a drug-polymer two-component system, the drug-polymer interaction is the determining factor in its design and performance.In this review, we summarize our current understanding of solid dispersions both in the solid state and in dissolution, emphasizing the fundamental aspects of this important technology.

View Article: PubMed Central - PubMed

Affiliation: Key Laboratory of Advanced Materials (MOE), Department of Chemical Engineering, Tsinghua University, Beijing 100084, China.

ABSTRACT
The solid dispersion has become an established solubilization technology for poorly water soluble drugs. Since a solid dispersion is basically a drug-polymer two-component system, the drug-polymer interaction is the determining factor in its design and performance. In this review, we summarize our current understanding of solid dispersions both in the solid state and in dissolution, emphasizing the fundamental aspects of this important technology.

No MeSH data available.


Schematic illustration of a solid dispersion in which a polymer chain is diffusing out of a drug domain.
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f0015: Schematic illustration of a solid dispersion in which a polymer chain is diffusing out of a drug domain.

Mentions: In a homogeneous drug–polymer solution, polymer chains are random coils that interpenetrate each other and extend through the whole system, while drug molecules are dispersed randomly among the polymer segments. It has been estimated that any continuous drug domain within the random coils is no larger than 2.5 nm26, so that for a drug to form stable crystal nuclei a certain amount of polymer must diffuse away. The time for this diffusion to occur can be calculated from the polymer diffusion coefficient, the lower limit of which can be calculated on the basis of the following two assumptions (Fig. 3): (1) The medium through which the polymer diffuses essentially consists of pure drug (in reality, the medium contains other polymer chains and the viscosity is much higher than that in a pure drug domain); (2) The medium viscosity is close to that at the glass transition temperature i.e. viscosity ~1012 Pa.s (again the storage temperature is usually below the glass transition temperature and the viscosity is much higher). With these assumptions and for a polymer about 10 nm in size, the diffusion coefficient of the polymer (the Rouse model27) is given by(1)D≅kT6πηR~10–26m2/sand the time for the polymer to diffuse over a distance of its own size (~10 nm) is(2)τ≅R2D~100years


Fundamental aspects of solid dispersion technology for poorly soluble drugs.

Huang Y, Dai WG - Acta Pharm Sin B (2013)

Schematic illustration of a solid dispersion in which a polymer chain is diffusing out of a drug domain.
© Copyright Policy - CC BY-NC-ND
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4590721&req=5

f0015: Schematic illustration of a solid dispersion in which a polymer chain is diffusing out of a drug domain.
Mentions: In a homogeneous drug–polymer solution, polymer chains are random coils that interpenetrate each other and extend through the whole system, while drug molecules are dispersed randomly among the polymer segments. It has been estimated that any continuous drug domain within the random coils is no larger than 2.5 nm26, so that for a drug to form stable crystal nuclei a certain amount of polymer must diffuse away. The time for this diffusion to occur can be calculated from the polymer diffusion coefficient, the lower limit of which can be calculated on the basis of the following two assumptions (Fig. 3): (1) The medium through which the polymer diffuses essentially consists of pure drug (in reality, the medium contains other polymer chains and the viscosity is much higher than that in a pure drug domain); (2) The medium viscosity is close to that at the glass transition temperature i.e. viscosity ~1012 Pa.s (again the storage temperature is usually below the glass transition temperature and the viscosity is much higher). With these assumptions and for a polymer about 10 nm in size, the diffusion coefficient of the polymer (the Rouse model27) is given by(1)D≅kT6πηR~10–26m2/sand the time for the polymer to diffuse over a distance of its own size (~10 nm) is(2)τ≅R2D~100years

Bottom Line: The solid dispersion has become an established solubilization technology for poorly water soluble drugs.Since a solid dispersion is basically a drug-polymer two-component system, the drug-polymer interaction is the determining factor in its design and performance.In this review, we summarize our current understanding of solid dispersions both in the solid state and in dissolution, emphasizing the fundamental aspects of this important technology.

View Article: PubMed Central - PubMed

Affiliation: Key Laboratory of Advanced Materials (MOE), Department of Chemical Engineering, Tsinghua University, Beijing 100084, China.

ABSTRACT
The solid dispersion has become an established solubilization technology for poorly water soluble drugs. Since a solid dispersion is basically a drug-polymer two-component system, the drug-polymer interaction is the determining factor in its design and performance. In this review, we summarize our current understanding of solid dispersions both in the solid state and in dissolution, emphasizing the fundamental aspects of this important technology.

No MeSH data available.