Linked Life Data

10425384

Source:http://linkedlifedata.com/resource/pubmed/id/10425384

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
1999-9-28
pubmed:abstractText
Chitosans are potent nontoxic absorption enhancers after nasal administration but their effects on the intestinal epithelium in vivo has not been studied in detail. In this study, the effects of chitosans with varying molecular weights and degrees of acetylation on the absorption of a poorly absorbed model drug (atenolol) were studied in intestinal epithelial cell layers with or without a mucus layer and in an in situ perfusion model of rat ileum. The effects of the chitosans on epithelial morphology and release of lactate dehydrogenase (LDH) into the perfusate were investigated in the in situ model. The chitosans had pronounced effects on the permeability of mucus-free Caco-2 layers and enhanced the permeation of atenolol 10- to 15-fold, with different absorption kinetics for different chitosans, in accordance with previous results. In contrast, enhancement of atenolol absorption through rat ileum was modest. LDH release from the tissues perfused with chitosans did not increase, indicating that the chitosans were used at nontoxic concentrations. Morphological examination of the perfused ileal tissues revealed more mucus discharge from the tissues exposed to chitosans than from controls, which suggested that the discharged mucus may inhibit the binding of chitosan to the epithelial surface and hence decrease the absorption-enhancing effect. This hypothesis was supported by studies with intestinal epithelial HT29-H goblet cells covered with a mucus layer. The binding of chitosan to the epithelial cell surface and subsequent absorption-enhancing effects were significantly reduced in mucus-covered HT29-H cultures. When the mucus layer was removed prior to the addition of chitosan, the cell surface binding and absorption-enhancing effects of the chitosans were increased. We conclude that the modest absorption-enhancing effects of unformulated chitosan solutions in the perfused rat ileum are a result of the mucus barrier in this tissue. This effect may be overcome by increasing the local concentrations of both chitosan and drug, i.e,. through formulation of the chitosan into a particulate dosage form.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
0928-0987
pubmed:author
pubmed:issnType
Print
pubmed:volume
8
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
335-43
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed-meshheading:10425384-Adrenergic beta-Antagonists, pubmed-meshheading:10425384-Animals, pubmed-meshheading:10425384-Atenolol, pubmed-meshheading:10425384-Biocompatible Materials, pubmed-meshheading:10425384-Biological Transport, pubmed-meshheading:10425384-Caco-2 Cells, pubmed-meshheading:10425384-Cell Membrane Permeability, pubmed-meshheading:10425384-Chitin, pubmed-meshheading:10425384-Chitosan, pubmed-meshheading:10425384-HT29 Cells, pubmed-meshheading:10425384-Humans, pubmed-meshheading:10425384-Ileum, pubmed-meshheading:10425384-Intestinal Absorption, pubmed-meshheading:10425384-Intestinal Mucosa, pubmed-meshheading:10425384-Male, pubmed-meshheading:10425384-Mucus, pubmed-meshheading:10425384-Perfusion, pubmed-meshheading:10425384-Rats, pubmed-meshheading:10425384-Rats, Sprague-Dawley
pubmed:year
1999
pubmed:articleTitle
Chitosans as absorption enhancers of poorly absorbable drugs. 3: Influence of mucus on absorption enhancement.
pubmed:affiliation
Department of Pharmaceutics, Uppsala University, Biomedical Center, P.O. Box 580, S-75123, Uppsala, Sweden. Nicolaas.Schipper@arcus.se.astra.com
pubmed:publicationType
Journal Article, Comparative Study, Research Support, Non-U.S. Gov't