Gastrointestinal tract evaluation

Spahn-Langguth H, Baktir G, Radschuweit A, et al. P-glycoprotein transporters and the gastrointestinal tract evaluation of the potential in vivo relevance of in vitro data employing talinolol as model compound. Int J Clin Pharmacol Ther 1998 36 (l) 16-24. 

Sucralfate [54182-58-0] an aluminum salt of sucrose octasulfate, is used as an antacid and antiulcer medication (59). Bis- and tris-platinum complexes of sucrose show promise as antitumor agents (60). Sucrose monoesters are used in some pharmaceutical preparations (21). A sucrose polyester is under evaluation as a contrast agent for magnetic resonance imaging (mri) (61). Oral adrninistration of this substance opacifies the gastrointestinal tract and eliminates the need for purging prior to mri. 

A number of the water-soluble polymers also have adhesive properties which are being extensively evaluated for drug delivery (9). These polymers will adhere to the mucous coating in the gastrointestinal tract, the nose, and the mouth to delay passage and sustain drug release. Those polymers with the best adhesive properties are those with hydroxyl and carboxyl groups. Table II lists some of the bioadhesive polymers and their adhesive properties. 

Interroute extrapolation. The values for pharmacokinetic variables in the O Flaherty Model are independent of the route of exposure. However, the model does incorporate media-specific estimates of absorption from the gastrointestinal tract. Different exposure scenarios have been evaluated with the O Flaherty Model for children and adults (O Flaherty 1993, 1995a). 

Such requirements are expected to assure that the dosage form is formulated and manufactured appropriately to ensure that the index or marker ingredients are uniformly distributed and will dissolve in the gastrointestinal tract and be available for absorption. No assumption is made that the marker or index compound selected for demonstration of dissolution is responsible for the purported effect. The test is valuable in that it assures that the formulation technology used is reflective of the state-of-the-art technology, provides a means to evaluate lot-to-lot performance over a product s shelf-life and that excipients used to facilitate transfer of the index or marker ingredients of the botanical to the human system are appropriate. 

All the above mentioned polymers have been evaluated mainly for application in the intestine. Finally, the last part of the gastrointestinal tract, the rectum should also be mentioned as a suitable site for delivery and fast absorption of therapeutics. Kim et al. [88] developed an in situ gelling and mucoadhesive acetaminophen liquid suppository prepared with poloxamers and sodium alginate. It was found that this particular formulation of acetaminophen in humans resulted in shorter T ax and higher maximum plasma concentrations of dmg (C ax) than the conventional acetaminophen suppositories. 

Akiyama, Y., Nagahara, N., Kashihara, T., Hirai, S., and Toguchi, H., In vitro and in vivo evaluation of mucoadhesive microspheres prepared for the gastrointestinal tract using polyglycerol esters of fatty acids and a poly(acrylic acid) derivative, Pharm. Res., 12 397-405... 

Decontamination procedures should be undertaken simultaneously with initial stabilization, diagnostic assessment, and laboratory evaluation. Decontamination involves removing toxins from the skin or gastrointestinal tract. 

Delie, F. (1998). Evaluation of nano- and microparticle uptake by the gastrointestinal tract. Advanced Drug Delwery Reviews, 34, 221-233. 

A comprehensive histology evaluation was performed in this study, but the liver is the only tissue specifically mentioned as having been examined. Due to the total number of tissues examined (21) and route of exposure, it is probable that the gastrointestinal tract was examined but not discussed because no histopathologic changes were observed. 

Recently, the pharmacokinetics of resveratrol from Smilax china, a rhizome extensively used in traditional Chinese medicine was evaluated [Huang et al., 2008]. Forty-five female rats were orally administered with 1 g/kg S. china extract equivalent to 180 mg/kg of oxyresveratrol and 80 mg/kg of resveratrol. The pharmacokinetic parameters showed that the two stilbenes were rapidly absorbed into the body fluid from the gastrointestinal tract and could still be detected in the plasma at least 6 h after the administration [Huang et al., 2008], probably due to the high dose administered. 

The most common cause of iron deficiency in adults is blood loss. Menstruating women lose about 30 mg of iron with each menstrual period women with heavy menstrual bleeding may lose much more. Thus, many premenopausal women have low iron stores or even iron deficiency. In men and postmenopausal women, the most common site of blood loss is the gastrointestinal tract. Patients with unexplained iron deficiency anemia should be evaluated for occult gastrointestinal bleeding. 

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