Oral route gastrointestinal tract

Oral. The oral route for dmg dehvery includes the gastrointestinal (GI) tract and the oral cavity including the buccal mucosa. The buccal mucosa is considered separately because of differences in the approach to dmg dehvery via this route. 

Insulin must be administered via the parenteral route, usually the subcutaneous (SC) route Insulin cannot be administered orally because it is a protein and readily destroyed in the gastrointestinal tract. Regular insulin is the only insulin preparation given intravenously (IV). Regular insulin is given 30 to 60 minutes before a meal to achieve optimal results. 

Delivery of peptides and proteins via the gastrointestinal tract has not been successful because of poor penetration through the intestinal epithelium and high levels of proteolytic activity in the gastrointestinal tract. Liposomal encapsulation of proteins and peptides will not improve the efficiency and capacity of this absorption pathway considerably (e.g., Ryman et al., 1982 Machy and Leserman, 1987 Weiner and Chia-Ming Chiang, 1988). These difficulties in delivery via the oral route caused the parenteral route to remain the preferred route for the administration of therapeutic peptides... 

Epinephrine is administered by a variety of different routes in anaphylaxis, except for the oral route, which is not feasible because of rapid inactivation of epinephrine in the gastrointestinal tract by catechol-O-methyltransferase and monoamine oxidase [9]. The initial intramuscular epinephrine doses of 0.3-0.5 mg currently recommended for adults with anaphylaxis are low compared with the doses required for resuscitation following cardiac arrest [1, 2,4,18]. 

Generally, tin compounds of 3-4 mgday-1 are ingested in the human body, and are absorbed poorly from the digestive tracts. 40% of the tin are excreted via urine and feces. Tin compounds tend to accumulate in liver, kidney and bone. By the oral route, high levels of tin compounds cause gastrointestinal symptoms such as nausea, vomiting and abdominal pain and headache. 

The toxicokinetics of disulfoton in humans and animals depends on its physicochemical characteristics and its metabolism. The lipophilicity of disulfoton indicates that the insecticide should be easily absorbed by oral, inhalation, and dermal routes. No bioavailability data were located for inhalation and dermal exposure. However, disulfoton is almost completely absorbed from the gastrointestinal tract within 2 days after oral exposure. Animal studies suggest that disulfoton is widely distributed primarily to the liver and in smaller quantities to the kidney, fat, skin, muscle, brain, and other organs. Disulfoton and/or its metabolites are excreted mainly in the urine of humans and animals, with minor amounts excreted in the feces and expired air. 

Orai Administration The oral route is the most common way of administering a drug. For a drug to be absorbed into the bloodstream, it has to be soluble in the fluids of our gastrointestinal tract. Drugs are often formulated with excipients (components other than the active drug) to improve manufacturing and dissolution processes (see Section 5.6). 

Intravenous Administration When a drug is injected, the entire dose can be considered as being available in the bloodstream to be distributed to the target site. Hence, the dosage can be controlled, unlike with other routes of administration, where the bioavailability of the drug may be unpredictable because of diffusion processes. Intravenous injection is the normal route for administration of protein-based drugs, as they are likely to be destroyed if taken orally because of the pH conditions in the gastrointestinal tract. 

Some of these triiodinated compounds are orally active, i.e. they are absorbed from the gastrointestinal tract after oral administration and imaging of the biliary system is possible following this route of administration. Examples are iopanoic acid, iophenoxic acid and sodium ipodate. A prerequisite for oral absorption is a balance of relatively hydrophilic and lipophilic moieties in the molecule. Numerous investigations have been performed to establish structure-activity relationships for this class of compounds, e.g. by Archer and Hoppe [70, 71]. Sodium salts are better absorbed than the free acids [72]. 

---