title: In situ gelling xyloglucan/pectin formulations for oral sustained drug delivery.
abstract: This study has examined the gelation and release characteristics of mixtures of xyloglucan, which has thermally reversible gelation characteristics, and pectin, the gelation of which is ion responsive, with the aim of formulating an in situ gelling vehicle suitable for oral sustained drug delivery. An investigation of the effect of the inclusion of pectin (0.75% (w/w)) on the rheological properties of gels formed from solutions of xyloglucan (1.5 and 2.0% (w/w)) showed a significantly greater gel strength when pectin was present in the formulation. The in vitro release of paracetamol from gels containing 1.5% (w/w) xyloglucan, and 1.5 or 2.0% (w/w) xyloglucan/0.75% (w/w) pectin was diffusion-controlled. Measurement of plasma levels of paracetamol after oral administration to rats of a solution containing 1.5% (w/w) xyloglucan and 0.75% (w/w) pectin showed that a more sustained release and higher drug bioavailability was achieved from the gels formed by the in situ gelation of this formulation compared to that of a 1.5% (w/w) xyloglucan solution; 0.75% (w/w) solutions of pectin did not form gels under these conditions. Visual observation of the contents of the rat stomach at intervals after oral administration showed that the inclusion of pectin in the xyloglucan solutions was effective in reducing gel erosion, so sustaining drug release.
authors.affiliation: Faculty of Pharmaceutical Sciences, Health Sciences University of Hokkaido, Ishikari-Tobetsu, Hokkaido 061-0293, Japan. itou@hoku-iryo-u.ac.jp
authors.forename: Kunihiko
authors.initials: K
authors.lastname: Itoh
authors.forename: Masayuki
authors.initials: M
authors.lastname: Yahaba
authors.forename: Akie
authors.initials: A
authors.lastname: Takahashi
authors.forename: Reina
authors.initials: R
authors.lastname: Tsuruya
authors.forename: Shozo
authors.initials: S
authors.lastname: Miyazaki
authors.forename: Masatake
authors.initials: M
authors.lastname: Dairaku
authors.forename: Mitsuo
authors.initials: M
authors.lastname: Togashi
authors.forename: Ryozo
authors.initials: R
authors.lastname: Mikami
authors.forename: David
authors.initials: D
authors.lastname: Attwood
mesh_terms: D000082:Acetaminophen / Q000008:administration & dosage* / Q000737:chemistry / Q000493:pharmacokinetics; D000284:Administration, Oral; D000818:Animals; D001682:Biological Availability; D003692:Delayed-Action Preparations; D004058:Diffusion; D005079:Excipients / Q000737:chemistry*; D005782:Gels; D005936:Glucans / Q000737:chemistry*; D008297:Male; D010368:Pectins / Q000737:chemistry*; D019999:Pharmaceutical Solutions; D051381:Rats; D017208:Rats, Wistar; D012212:Rheology; D014990:Xylans / Q000737:chemistry*
chemical_list: D003692:Delayed-Action Preparations; D005079:Excipients; D005782:Gels; D005936:Glucans; D019999:Pharmaceutical Solutions; D014990:Xylans; D000082:Acetaminophen; C029353:xyloglucan; D010368:Pectins