Bioavailability Enhancement Through Gastrointestinal Retention
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Gastro-retentive drug delivery systems (GRDDS) are designed on the basis of delayed gastric emptying and CR principles.
BIOAVAILABILITY ENHANCEMENT THROUGH GASTROINTESTINAL RETENTION
Gastro-retentive drug delivery systems (GRDDS) are
designed on the basis of delayed gastric emptying and CR principles, and are
intended to restrain and localize the drug delivery device in the stomach or
within the upper parts of the small intestine until the entire drug is
released. Excipients that are bioadhesive or that swell on hydration when
incorporated in an oral dosage form, can promote gastro-retention and
absorption by –
·
Increased contact with epithelial
surfaces
·
Prolonging residence time in the
stomach
·
Delaying intestinal transit.
Cellulose ethers, gums of natural origin, and
synthetic acrylic acid polymers have been evaluated for such purposes. The
range of materials available and their differing viscoelastic and rheological
behaviours mean that it is possible, by judicious admixture, to develop
delivery units with balanced properties so that adhesion, density, hydration,
drug release rate, etc. can be tailored to the drug in question and the
physiological characteristics of the target delivery site.
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