Oral tablets for ingestion:Targeted tablet
From Pharmpedia
Next Page: Chewable tablet
Previous Page: Delayed action tablet
When we need to release the API at a specific site in the elementary tract, targeted drug delivery is a preferred option. Depending upon the composition and release mechanism of a tablet, the drug is delivered to a particular region. Under this category, we have two types of tablet:
I.Gastro retentive Tablet
This type of dosage form is to be opted when API release is desired in stomach (Antacids, APIs used against H.pylori infection) or site of absorption is either stomach or upper part of small intestine.
FIGURE.10. FLOATING TABLET
To retain the drug for longer time period in stomach, following approaches can be used:
i) Low density tablet (effervescent or non effervescent)
ii) Tablets that can expand in gastric environment (swelling or by unfolding) and thus increasing the size so that it cannot cross the pyloric sphincter.
iii) Using mucoadhesive polymers that stick to mucosa of stomach and provide slow drug release.
Supine position is to be avoided and also high level of fluid is necessary or if the swelling formulation leaves stomach before it swells it’s ineffective. Drugs like Diazepam, Levodopa, Benserazide, and Ciprofloxacin are successfully marketed in this formulation.
II. Colonic tablets(7,8)
When the aim is to deliver the drug into colon without dilution in other regions of gastrointestinal tract or the drug has poor absorption in stomach or small intestine, colonic drug delivery is an answer of choice. The pH in this region varies from 6.4 - 7 and presence of microbial flora plays as important role in drug release especially in this region. Various mechanisms are adopted for drug release in this area are coating with pH sensitive polymer e.g., Eudragit®S100, Eudragit® L100, biodegradable polymer like polymers which are sensitive to colonic bacteria, bioadhesive polymers which selectively sticks to colonic mucosa e.g., polycarbophils or polyethans, redox sensitive polymers that respond to redox potential in colon which expresses the total metabolic and bacterial action.
Next Page: Chewable
tablet
Previous Page: Delayed action tablet
Retrieved from "http://www.pharmpedia.com/Oral_tablets_for_ingestion:Targeted_tablet"
This page has been accessed 1,517 times. This page was last modified 21:35, 8 August 2005. All content, except where otherwise noted, is licensed under a Creative Commons Attribution License.
