Enteric coating

The insolubility of the esters of MA-MVE or MA-St copolymers in acidic media and their solubility in basic environments represent an advantage for controlled drug delivery in the gastrointestinal tract when the drug should not be released in the acidic pH of the stomach, but in the intestine [140-144]. Table 10.3 presents the application of maleic copolymer as enteric coatings. 

The solubility in organic solvents of the copolymers in the maleic form allows their deposition from acetone, ethyl acetate, or acetone-isopropanol mixture. Tablets or granules can be covered by immersion into polymeric solution or by spraying. If the MA-MVE coated tablets showed a rapid disintegration in the stomach [140], when alkyl esters of MA-MVE were used for coating, the in-vivo absorption of the drug was delayed and the duration of action was increased [141-143]. 

MA-MVE ethyl ester, MA-MVE isopropyl ester, MA-MVE buthyl ester, MA-MVE cyclopenthyl ester ScJicyKc acid (tablets) 143 

MA-MVE hydrochlorothiazide (diuretic), indomethacin (anti-inflammatory), nalidixic acid (antibacterial), reserpine (anti-hypertensive) 145 

MA-MVE, MA-MVE ethyl ester, MA-MVE nonylphenoxy-poly-(ethylenoxy) ethanol griseofulvin (antifungal, antibiotic) 146 

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Ent. cloacae P99-Enteric bacteria Enteric coatings Enteritis Enterobacter... 

Enteric coating is also used for repeat-action tablets, which contain an enteric-coated core tablet and a sugar or film-coated second dose, permitting the adininistration of two doses simultaneously. The core dose is released several hours after the initial, outer dose. 

Uses. Aspirin has analgesic, antiinflammatory, and antipyretic activity. It is used for the reHef of less severe types of pain, such as headache, neuritis, acute and chronic rheumatoid arthritis, and toothache. Aspirin can be purchased in a variety of OTC and prescription dosage forms made and formulated by many companies. Tablets, ie, buffered, plain, or enteric-coated, are the most familiar in the United States, but other forms such as powder and effervescent formulations are of considerable importance in other parts of the world. 

Delivery systems that respond to changes in pH have been known to the pharmaceutical industry for more than a century. The pH-sensitive enteric coating is probably the oldest controUed-release technology. Unna introduced an enteric tablet coating based on keratin in 1884 (108). Enteric coatings are used primarily to protect the gastric mucosa from local irritation or to ensure that tablets do not dissolve until they reach the intestine. 

DIGESTIVE ENZYMES. When digestive enzymes are given in capsule or enteric-coated tablet form, the nurse... 

Oral administration of bicarbonate may decrease the absorption of ketoconazole. Increased blood levels of quinidine, flecainide, or sympatiiomimetics may occur when these agents are administered with bicarbonate There is an increased risk of crystalluria when bicarbonate is administered with the fluoroquinolones. Fbssible decreased effects of lithium, methotrexate, chlorpropamide, salicylates, and tetracyclines may occur when these drag s are administered with sodium bicarbonate. Sodium bicarbonate is not administered within 2 hours of enteric-coated drugs the protective enteric coating may disintegrate before the drug reaches the intestine. 

If the tablet has a coating (enteric-coated tablets), swallow it whole. Do not chew or crush the tablet. 

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-... 

Neural networks have also been used in Slovenia, to model the release characteristics of diclofenac [52] in China, to study release of nifedipine and nomodipine [53] and in Yugoslavia to model the release of aspirin [54], More recently, work in this area has been extended to model osmotic pumps in China [55] and enteric coated tablets in Ireland [56],... 

Turkoglu M, Varol H, Celikok M. Tableting and stability evaluation of enteric-coated omeprazole pellets. Eur J Pharm Biopharm 2004 57 277-86. 

Any extended release preparation ° CR—controlled-release ° EC—enteric coated ° LA—long-acting ° SR—sustained release 0 TR—time release ° SA—sustained action ° SL—sublingual ° XL—extended length ° XR—extended release... 

Shark cartilage 3 tablets by mouth daily Enteric-coated aspirin 81 mg by mouth daily Ginseng 2 tablets by mouth daily... 

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. 

Comparable daily doses of PPIs are omeprazole 20 mg = esomeprazole 20 mg = lansoprazole 30 mg = rabeprazole 20 mg = pantoprazole 40 mg. The PPIs degrade in acidic environments and are therefore formulated in delayed-release capsules or tablets.16 Lansoprazole, esomeprazole, and omeprazole contain enteric-coated (pH-sensitive) granules in a capsule form. For patients unable to swallow the capsule or in pediatric patients, the contents of the capsule can be mixed in applesauce or placed in orange juice. If a patient has a nasogastric tube, the contents of an omeprazole capsule can be... 

Sulfasalazine Azulfidine Azulfidine Entabs Sulfazine Sulfazine EC Immediate-release or enteric-coated tablets 500 mg 2-6 g Colon... 

Peppermint oil is widely advocated it acts as an antispas-modic agent due to its ability to relax gastrointestinal smooth muscle. However, it also relaxes the lower esophageal sphincter, which could allow reflux of gastric contents into the esophagus. The usual dose is 1 to 2 enteric-coated capsules containing 0.2 mL of peppermint oil two to three times daily. 

Non-enteric-coated pancreatic enzyme supplements require high doses to compensate for loss of enzyme due to... 

C, powder encased in a cellulose capsule ECMS, enteric-coated microspheres encased in a cellulose or gelatin capsule ECMT, enteric-coated microtablets encased in a cellulose capsule UCT, uncoated tablet P, powder. 

Non-enteric-coated pancreatic enzyme supplements can be used for initial therapy. The relative dose of amylase, lipase, and protease may be increased until control of pain and fatty diarrhea is achieved or the patient experiences intolerable side effects. If pain and diarrhea control are achieved, the patient can be transitioned to an enteric-coated supplement to maximize compliance. A reasonable example starting regimen is Viokase-8, six tablets with each meal and at bedtime, given with famotidine 20 mg at bedtime. 

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... 

Pancreatic enzyme supplements should be taken immediately prior to meals to aid in the digestion and absorption of food. Alternately, patients can supplement their diet with medium chain triglycerides (MCTs) or ingest foods rich in MCTs since they do not require pancreatic enzymes for absorption. An appropriate regimen incorporates the successful doses of each enzyme (amylase, lipase, and protease) from the starting non-enteric-coated regimen. As with the previous example, a patient stabilized on Viokase-8, six tablets with each meal, can be transitioned to Pancrease MT-16 three tablets with meals. The famotidine can then be discontinued. 

Optimize pancreatic enzyme supplementation, starting first with a non-enteric-coated enzyme supplement and an H2RA. When pain and diarrhea are stabilized, consider switching to an enteric-coated enzyme supplement for ease of dosing. 

Divalproex sodium Depakote Enteric-coated, 750-3000 mg/day (20-60 mg/kg Monotherapy or in... 

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... 

Enteric-coated MPA (Myfortic ) 720 mg by mouth twice Myelosuppression, gastrointestinal 180 mg = 2.53... 

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