Stomach enteric coatings

Most pancreatic enzyme supplements are enteric coated to release enzymes in the alkaline environment of the intestine this minimizes enzyme destruction in the stomach. Enteric-coated pancreatic enzyme supplements require fewer daily dosage units, but delivery of the drug to the site of action and effectiveness may be delayed by gastric emptying time.41... 

Enteric Coated Intended to delay the release of the drug (or drugs) until the dosage form has passed through the stomach. Enteric coated products are delayed release dosage forms. 

Chitosan would not seem suitable as a pH-sensitive polymer because it is soluble at acidic pH values, and becomes insoluble approximately at pH 6.5. Nevertheless, an enteric coating can protect chitosan from the acidity of the stomach. When the preparation reaches the intestine, the en-... 

Pancreatic enzyme replacement is the mainstay of gastrointestinal therapy. Most enzyme products are formulated as capsules containing enteric-coated microspheres or microtablets to avoid inactivation of enzymes in the acidic stomach instead, they dissolve in the more alkaline environment of the duodenum. Capsules may be opened and the microbeads swallowed with food, as long as they are not chewed. A powder form is available for patients unable to swallow the capsules or microbeads, but bioavailability is poor. While products may contain similar enzyme ratios, they are not bioequivalent and cannot be substituted. Generic enzyme products generally display poor dissolution and should not be used.5 Table 13-3 lists commonly used enzyme replacement products. 

Syrup/suspension/ solution Extended-release/ enteric-coated tablets Faster rate of absorption 100% Delayed absorption 60-90% Faster rate of absorption Delayed absorption 89% of the suspension and less than regular-release tablets Unknown NA Faster rate of absorption than tablets Extended-release 90% of intravenous dose. Delayed-release 81-90% of intravenous dose Delayed absorption with delayed-release tablets valproate is rapidlyconverted to VPA in the stomach, then is rapidly and almost completely absorbed from the Gl tract NA NA... 

A drug should always be ingested with a cup of water ( 8 oz) to insure easy transit down the esophagus and to provide fluid for disintegration and dissolution. Whether or not the drug should be taken on an empty stomach (e.g., enteric-coated tablets) or with food will depend upon the specific drug as noted above. 

Enteric-coated tablets or capsules of garlic are better absorbed since an active ingredient, allicin, is acid labile. The tablets or capsules bypass the stomach and release their contents in the alkaline medium of the small intestine [4],... 

Encapsulation within an enteric coat (resistant to low pH values) protects the product during stomach transit. Microcapsules/spheres utilized have been made from various polymeric substances, including cellulose, polyvinyl alcohol, polymethylacrylates and polystyrene. Delivery systems based upon the use of liposomes and cyclodextrin-protective coats have also been developed. Included in some such systems also are protease inhibitors, such as aprotinin and ovomucoids. Permeation enhancers employed are usually detergent-based substances, which can enhance absorption through the gastrointestinal lining. 

Pancreatin is a pancreatic extract usually obtained from the pancrease of slaughterhouse animals. It contains a mixture of enzymes, principally amylase, protease and lipase, and, thus, exhibits a broad digestive capability. It is administered orally mainly for the treatment of pancreatic insufficiency caused by cystic fibrosis or pancreatitis. As it is sensitive to stomach acid, it must be administered in high doses or, more usually, as enteric-coated granules or capsules that may be taken directly or sprinkled upon the food prior to its ingestion. Individual digestive activities, such as papain, pepsin or bromelains (proteases), or a-amylase are sometimes used in place of pancreatin. 

The reason for the problems is often that the characteristics of the medication are changed. Depot formulation loses its slow release properties with increased peak-and decreased through concentrations. Enteric coating is destroyed with stomach... 

Enteric coated tablets are designed to resist the acidic environment in the stomach and release the medication in the small intestine. If such tablets are broken, their enteric properties may be lost. Therefore, do not break them. 

The solubility should be measured at all of these pH values with a suitable, validated method such as shake-flask or pSol (2) at 37°C to determine whether the (envisaged) dose of the drug can be completely dissolved at all points of interest in the GI tract (see Chapter 11 for more discussion of solubility determination). Typically, this would be the upper GI pH (stomach and proximal small intestine) for immediate release (IR) products, the pH in the small intestine for enteric-coated products and, additionally for MR dosage forms intended to release over a period of six hours or more, the pH in the proximal colon. 

For some products, e.g., propanolol extended release formulations (USP 27), a modification of the standard method for enteric-coated dosage forms have been introduced to reflect the change from conditions in the stomach to those in the small intestine. This is a step in the right direction, but to achieve dissolution testing that can differentiate between formulations which are robust and those which are not, and especially to be able to predict food effects on the release from... 

Enteric coating materials not only protect a dosage form from the acidic environment in the stomach and allow drug delivery to the small intestine, they may also pass through the... 

Absorption/Distribution - Most of these oral agents contain enteric-coated granules. Absorption of these agents is rapid and begins only after the granules leave the stomach. 

Enteric-coated capsules In the presence of food, C ax AUC for didanosine capsules were reduced by approximately 46% and 19%, respectively, compared with the fasting state. Take didanosine capsules on an empty stomach. 

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