Journal ArticleDOI
Evaluation of guar gum in the preparation of sustained-release matrix tablets.
TLDR
The mechanism of behavior of guar gum in a polymer-drug matrix, where an inverse relationship exists between the drug concentration in the gel and matrix swelling, is examined to suggest that guar Gum swelling is one of the factors affecting drug release.Abstract:
Polymeric hydrophilic matrices are widely used for controlled-release preparations. The process of drug release is controlled by matrix swelling or polymer dissolution. It has been shown that the swelling of guar gum is affected by concentration of drug and viscosity grade of the polymer. This study examines the mechanism of behavior of guar gum in a polymer-drug matrix. The swelling action of guar gum, in turn, is controlled by the rate of water uptake into the matrices. An inverse relationship exists between the drug concentration in the gel and matrix swelling. This implies that guar gum swelling is one of the factors affecting drug release. The swelling behavior of guar gum is therefore useful in predicting drug release.read more
Citations
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Journal ArticleDOI
Natural Gums and Modified Natural Gums as Sustained-Release Carriers
TL;DR: In this review, recent developments in the area of natural gums and their derivatives as carriers in the sustained release of drugs are explored.
Gums and mucilages: versatile excipients for pharmaceutical formulations
TL;DR: This review describes the developments in natural gums and mucilages for use in the pharmaceutical sciences and describes how these natural materials can compete with the available synthetic excipients.
Journal ArticleDOI
Compressed xanthan and karaya gum matrices: hydration, erosion and drug release mechanisms.
D.L. Munday,Philip J. Cox +1 more
TL;DR: Directly compressed matrices were produced containing either xanthan gum or karaya gum as a release-controlling agent to control the release of varying proportions of two model drugs which have different solubilities in aqueous medium.
Journal ArticleDOI
Modified guar gum matrix tablet for controlled release of diltiazem hydrochloride.
TL;DR: Nature of drug transport through the polymer matrices was studied by comparing with Higuchi, Hixson-Crowell and Kopcha equations and drug release was found to be dissolution-controlled in case of unhydrolyzed copolymer.
Journal ArticleDOI
Xanthan and galactomannan (from M. scabrella) matrix tablets for oral controlled delivery of theophylline
TL;DR: Directly compressed theophylline tablets, containing commercial xanthan (X) (Keltrol) and a highly hydrophilic galactomannan (G) from the seeds of Mimosa scabrella as release-controlling agents, were obtained and provided the required release rate, with zero-order release kinetics.
References
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Book
Encyclopedia of polymer science and engineering
TL;DR: In this paper, the authors describe a chain transfer characterisation of polymers charge-transfer complexes, charge transfer complexes and charge transfer complexes of charge transfer and charge-Transfer complexes.
Journal Article
Sustained- and controlled-release drug delivery systems
G. M. Grass,J. R. Robinson +1 more
Journal ArticleDOI
Hydrogels for controlled drug delivery
Neil B. Graham,Marion E. McNeill +1 more
TL;DR: Physical properties such as number average molecular weight Mn, specific hydrates and changing diffusion coefficient of crystalline/rubbery hydrogels based on poly(ethylene glycol) Mn 3 000-8 000 which affect the diffusion of drugs through the water swollen matrix and across the polymer boundary are discussed.
Journal ArticleDOI
Controlled release of water-soluble macromolecules from bioerodible hydrogels.
TL;DR: A bioerodible hydrogel based on water-soluble unsaturated polyesters crosslinked through the double bonds and capable of immobilizing water- soluble macromolecules has been developed.
Journal ArticleDOI
Relationship Between Swelling and Drug Release in a Hydrophilic Matrix
TL;DR: In this article, the authors examined the mechanism of behaviour of HPMC in a polymer-drug directly-compressed matrix and showed that the swelling of the polypropylmethylcellulose (HPMC) is affected by concentration and viscosity grade of the polymer.