Effect of Ca2+-alginate gel dissolution on release of dextran with different molecular weights.
J Control Release
; 58(1): 21-8, 1999 Mar 08.
Article
en En
| MEDLINE
| ID: mdl-10021486
Release of macromolecular drug from calcium-alginate gel beads was investigated. Fluorescein isothiocyanate-labeled dextrans with molecular weight ranging from 9400 to 145000 were used as a model macromolecular drug. Dextran release was observed to be molecular weight-dependent, with the release pattern changing from pseudo first-order for dextran with 9400 molecular weight to sigmoidal for dextran with molecular weight of 145000. Release of a lower molecular weight dextran is mainly governed by the drug diffusion through the calcium-alginate gel matrix. With increasing dextran molecular weights, dextran release was strongly influenced by the dissolution of alginate matrix through the exchange of Ca2+ ions which act as a cross-linker. Rapid and complete release was achieved for dextran with 145000 molecular weight in a "burst" fashion showing a initial lag time. Minimal dextran release was observed in pseudo-gastric fluid at pH 1.2, while rapid dextran release within a narrow time range was achieved in simulated intestinal fluid at pH 6. 8. These results strongly suggest that calcium-alginate gel is a useful vehicle for pulsatile release of macromolecular drugs in oral drug delivery.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Dextranos
/
Alginatos
Idioma:
En
Revista:
J Control Release
Asunto de la revista:
FARMACOLOGIA
Año:
1999
Tipo del documento:
Article
País de afiliación:
Japón
Pais de publicación:
Países Bajos