Oral route of drug administration

Oral Delivery Systems. The oral route of drug administration has been the most popular one, however, it is not without problems and constrains. First of all, the total gastrointestinal residence time limits the time frame or "window" for oral absorption. The... 

The oral route of drug administration may be indicated for some conditions in pediatric patients, such as in dacryocystitis and orbital or preseptal cellulitis. Young patients are able to swallow liquid suspensions and solutions more easily than oral solids (e.g., tablets or capsules). Oral medications are the most reliable form of dosing and delivery and continue to be the mainstay in pediatric drug therapy. 

Historically, the oral route of drug administration has been the one nsed most for both conventional as well as novel drug delivery. The reasons for this preference are obvious because of the ease of administration and widespread acceptance by patients. Major limitations of oral route of drug administration are as follows ... 

The oral route is the most frequent route of drug administration and rarely causes physical discomfort in patients. Oral drug forms include tablets, capsules, and liquids. Some capsules and tablets contain sustained-release drag s, which dissolve over an extended period of time. Administration of oral dru is relatively easy for patients who are alert and can swallow. 

The transdermal route of drug administration offers several advantages over other methods of delivery. For some cases, oral delivery may be contraindicated, or the drug may be poorly absorbed. This would also include situations for which the drug undergoes a substantial first-pass effect [173] and systemic therapy is desired. 

Despite tremendous innovations in the field of drug delivery technology, oral intake remains the preferred route of drug administration, for reasons of patient convenience and therapy compliance. Compounds intended for oral administration must have adequate biopharmaceutical properties in order to achieve therapeutic concentrations at the targeted site of action. 

Poor correlation may be found between response and plasma concentration of parent drug if active metabolites are present and not measured. Formation of active metabolites may be a function of the route of drug administration because oral ingestion generally produces an initial surge of metabolites due to the first-pass effect of the liver compared with drugs administered intravenously. 

In the past two decades, many studies have tested adjuvants that act by either permeabilizing the rectal mucosa or inhibiting drug degradation. Oral and rectal routes of drug administration are unsuitable for adequate absorption of various compounds with a peptide or protein structure and of several hydrophilic antibiotics. The use of absorption enhancers, e.g., salicylates, enamines, surfactants, and straight-chain fatty acids, has gained wide interest... 

Today, there are a number of methods that can be used to introduce a drug into the body. Because of its convenience, the most common delivery system is the oral route. However, sometimes the oral route is not the most appropriate. In addition to the oral route, some of the alternative routes of drug administration with the oldest history include, not surprisingly, inhalation, and, surprisingly, rectal and vaginal, as illustrated by the following examples. 

The oral route is, of course, the principal enteral route of drug administration. However, two other examples are worthy of note. First, the sublingual route (beneath the tongue) provides relatively good absorption because of its rich capillary bed it is routinely used for the administration of nitroglycerin tablets in the treatment of... 

All routes of drug administration can affect ocular structures and functions. OADRs have been associated with topical ophthalmic administrations as well as local injections. Systemically, oral drug administration has been implicated most frequently in the development of OADRs. However, parenteral as well as inhaled or nasally applied drugs have also produced OADRs. Topical application to the skin, particularly if it is abraded or burned, may result in sufficient systemic absorption to lead to ocular side effects. Dermatologic use of antibiotics has resulted in ocular hypersensitivity reactions. 

Oral (PO) Absorption may vary Generally slower absorption rate compared to IV bolus or IM injection Safest and easiest route of drug administration May use immediate-release and modified-release drug products Some drugs may have erratic absorption, be unstable in the gastointestinal tract, or be metabolized by liver prior to systemic absorption... 

Oral administration is the most common route of drug administration. Major physiologic processes in the GI system include secretion, digestion, and absorption. Secretion includes the transport of fluid, electrolytes, peptides, and proteins into the lumen of the alimentary canal. Enzymes in saliva and pancreatic secretions are involved in the digestion of carbohydrates and proteins. Other secretions such as mucus protect the linings of the lumen of the GI tract. Digestion is the breakdown of food constituents into smaller structures in preparation for absorption. Both drug and food constituents are mostly absorbed in the proximal area (duodenum) of the small intestinal. The process of absorption is the entry of constituents from the lumen of the gut into the body. Absorption may be considered as the net result of both lumen-to-blood and blood-to-lumen transport movements. 

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