Excipient effects on gastrointestinal transit and drug absorption in beagle dogs

Julia D R Schulze1, Erin E Peters, Ann W Vickers

  • 1Department of Pharmaceutics, The School of Pharmacy, University of London, 29-39 Brunswick Square, London WC1N 1AX, UK.

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Factors Influencing Drug Absorption: Disease States and Pharmacology01:25

Factors Influencing Drug Absorption: Disease States and Pharmacology

Multiple disease states can significantly influence the oral drug absorption process by affecting blood flow and the functionality of the gastrointestinal (GI) system. Various GI diseases, including conditions that alter GI motility, such as diarrhea, decreased acid secretions (achlorhydria), and infections, have been associated with reduced drug absorption.
Substances such as alcohol and specific drugs, including antineoplastics, can also negatively impact drug absorption. For instance,...
Drug Absorption: Factors Affecting GI Absorption01:19

Drug Absorption: Factors Affecting GI Absorption

The process of oral drug absorption can be influenced by several factors. Weakly acidic drugs tend to be absorbed more readily from the stomach due to their nonionized state. However, absorption may be less efficient in the upper intestine, where drugs are often ionized. Interestingly, despite the stomach's apparent advantage for drug absorption, its mucous layer can hinder diffusion. Its surface area is also smaller than the intestine's, which can further slow down the absorption rate.
In...
Factors Affecting Dissolution: Drug Permeability, Stability and Stereochemistry01:20

Factors Affecting Dissolution: Drug Permeability, Stability and Stereochemistry

Orally administered drugs primarily enter the systemic circulation via passive diffusion through the intestinal membranes. The drug's absorption is influenced by drug stability in the gastrointestinal GI tract, membrane permeability, the surface area available for absorption, luminal drug concentration, and residence time in the lumen. Drug permeability can be enhanced by adjusting the lipophilicity, polarity, or molecular size of the drug, promoting its passive transport across intestinal...
Factors Influencing Drug Absorption: Anatomical Parameters01:23

Factors Influencing Drug Absorption: Anatomical Parameters

Drug absorption involves the movement of drugs from the point of administration into the systemic circulation. Initially, Gastrointestinal (GI) motility propels the drug through the digestive tract and into the stomach. However, the stomach's high acidity and limited surface area restrict its role in drug absorption for most drugs. The drug then moves from the stomach to the small intestine via gastric emptying, which can be slowed by various factors, including interactions with other...
Bioavailability Enhancement: Drug Stability Enhancement and GI Retention01:05

Bioavailability Enhancement: Drug Stability Enhancement and GI Retention

Improving a drug's stability in the gastrointestinal (GI) tract is paramount for enhancing its bioavailability and therapeutic effectiveness. Various strategies are employed to protect the drug from the harsh gastric milieu and to ensure its release and absorption at the desired site within the GI tract.Polymer coatings are one such method used to shield drugs from the stomach's acidic environment. By preventing premature drug release, these coatings improve the bioavailability of unstable...
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Drugs Affecting GI Tract Motility: Adsorbents as Antidiarrheal Agents

Diarrhea is characterized by the occurrence of frequent, watery bowel movements. Various factors can trigger diarrhea, including viral or bacterial infections, foodborne illnesses, side effects from certain medications, and underlying digestive disorders. If not adequately managed, diarrhea can lead to complications such as dehydration, electrolyte imbalances, and nutrient deficiencies. Severe diarrhea can lead to significant weight loss, malnutrition, and weakened immune function.
Adsorbents...