Biopharmaceutics Part A - Specific Aims

What is the primary role of the pyloric sphincter?

Which of the following factors is least likely to affect the rate of drug absorption in the small intestine?

Which of the following characteristics is not typically associated with passive diffusion of drugs across the GI membrane?

Under what conditions are 'sink conditions' maintained during drug absorption via diffusion across the GI membrane?

Which of the following statements accurately describes the relationship between gastric residence time and the size of a dosage form?

Which of the following factors is most likely to affect the ability of drugs to be absorbed in the colon?

How can gastrointestinal pH affect drug absorption?

Which of the following statements accurately describes active transport of drugs across the GI membrane?

Biopharmaceutics Part A - Specific Aims

Oral administration advantages
Gastrointestinal (GI) tract components and function
Mucus: roles, components, turnover time
Stomach: volumes (fed/fasting), pH, secretions, motility patterns, pyloric sphincter role, MMC phase III location
Small intestine: roles, length, pH, absorption factors
Colon: roles, length, pH, absorption factors
Drug gastric residence time
Factors affecting residence time: dosage form size, meal, administration with water vs. food
Transit times: small and large intestines
Barriers to drug absorption
GI lumen and unstirred water layer
Gastrointestinal pH, food (including grapefruit juice), disease states, and luminal enzymes
Drug transport across GI membrane
Membrane characteristics
Passive diffusion: factors affecting rate, sink condition maintenance, drug concentration in blood vs. GI fluids
Active transport: carrier-mediated, energy investment, saturability, relevant molecules, multiple transport mechanisms
Facilitated diffusion: importance for drug absorption
Endocytosis: major types
Paracellular pathway: types of drugs using this mechanism
Drug efflux in the intestine
Main protein in small intestine
Efflux impact on bioavailability
Review questions

Explore the intricate details of biopharmaceutics, focusing on the advantages of oral administration and the functionality of the GI tract components. This quiz covers aspects such as drug absorption, gastric residence time, and the physiological factors affecting drug transport across the gastrointestinal membrane. Test your understanding of how various elements influence drug efficacy.