Pharmacokinetics and Drug Absorption Quiz

Pharmacokinetics and Drug Absorption

• Intranasal administration delivers drugs directly to the nasal cavity for local or systemic effects, bypassing the hepatic first-pass effect.
• Intrathecal administration introduces drugs directly into the cerebrospinal fluid to overcome the blood-brain barrier, used for CNS infections and cancer treatment, but it can be painful.
• Topical administration is used for local drug effects, such as applying creams to the skin or using eye drops.
• Transdermal administration involves applying drugs to the skin via patches for systemic distribution and effects, affected by skin characteristics and diseases.
• Pharmacokinetics examines drug movement through the body, focusing on absorption, distribution, metabolism, and excretion (ADME).
• Drug absorption involves the transfer of a drug from its site of administration to the systemic bloodstream circulation, occurring through various processes like simple diffusion, facilitated diffusion, active transport, and endocytosis/exocytosis.
• Simple diffusion allows drugs to move along their concentration gradient without requiring energy or a carrier protein, with the rate dependent on the drug's physicochemical properties.
• Facilitated diffusion requires transmembrane carrier proteins and moves drugs according to their concentration gradient without needing energy, but it is saturable and can be inhibited.
• Active transport involves specific carrier proteins, is energy-dependent, and moves drugs against their concentration gradient, being saturable and inhibitable.
• Endocytosis and exocytosis transport large-sized drugs through engulfment by the cell membrane and transport into or out of the cell, respectively.
• Factors influencing drug absorption include pH, blood flow to the absorption site, total surface area available for absorption, and contact time at the absorption surface, with pH affecting drug ionization and thus permeation through membranes.
• The pKa of a drug, a measure of its interaction with a proton, influences the ratio of its ionized and unionized forms, affecting absorption based on the drug's acidity or basicity, and blood flow and surface area at the absorption site also impact drug absorption.

Pharmacokinetics and Drug Absorption

• Intranasal administration delivers drugs directly to the nasal cavity for local or systemic effects, bypassing the hepatic first-pass effect.
• Intrathecal administration introduces drugs directly into the cerebrospinal fluid to overcome the blood-brain barrier, used for CNS infections and cancer treatment, but it can be painful.
• Topical administration is used for local drug effects, such as applying creams to the skin or using eye drops.
• Transdermal administration involves applying drugs to the skin via patches for systemic distribution and effects, affected by skin characteristics and diseases.
• Pharmacokinetics examines drug movement through the body, focusing on absorption, distribution, metabolism, and excretion (ADME).
• Drug absorption involves the transfer of a drug from its site of administration to the systemic bloodstream circulation, occurring through various processes like simple diffusion, facilitated diffusion, active transport, and endocytosis/exocytosis.
• Simple diffusion allows drugs to move along their concentration gradient without requiring energy or a carrier protein, with the rate dependent on the drug's physicochemical properties.
• Facilitated diffusion requires transmembrane carrier proteins and moves drugs according to their concentration gradient without needing energy, but it is saturable and can be inhibited.
• Active transport involves specific carrier proteins, is energy-dependent, and moves drugs against their concentration gradient, being saturable and inhibitable.
• Endocytosis and exocytosis transport large-sized drugs through engulfment by the cell membrane and transport into or out of the cell, respectively.
• Factors influencing drug absorption include pH, blood flow to the absorption site, total surface area available for absorption, and contact time at the absorption surface, with pH affecting drug ionization and thus permeation through membranes.
• The pKa of a drug, a measure of its interaction with a proton, influences the ratio of its ionized and unionized forms, affecting absorption based on the drug's acidity or basicity, and blood flow and surface area at the absorption site also impact drug absorption.

Pharmacokinetics and Bioavailability in Drug Absorption and Distribution

• P-glycoprotein is a transmembrane transporter protein that can decrease drug absorption and therapeutic concentration, as well as cross the blood-brain barrier.
• The route of administration affects drug absorption, with IV administration providing 100% bioavailability due to bypassing the absorption process.
• Chemical characteristics, dosage form, and health status influence drug absorption and bioavailability.
• Bioavailability is the percentage of the administered dose of a drug that reaches the systemic circulation.
• Factors influencing bioavailability include first-pass hepatic metabolism, extent of absorption, chemical instability, and drug solubility.
• Bioequivalence measures comparable bioavailability and time to achieve maximum blood concentration of related drug products.
• Therapeutic equivalence requires bioequivalence and pharmaceutical equivalence, ensuring comparable efficacy and safety.
• Pharmacokinetics examines drug movement through the body, including absorption, distribution, metabolism, and excretion (ADME).
• Drug distribution depends on factors such as blood flow, capillary permeability, and binding to plasma proteins.
• Volume of distribution (Vd) is a hypothetical volume of fluid into which a drug is dispersed and varies based on drug properties.
• The volume of distribution has three compartments: plasma, extracellular fluid, and total body water, each influencing drug distribution differently.
• Drug binding to plasma proteins, such as albumin, influences drug activity, availability for elimination, and potential competition between drugs at binding sites.

Test your knowledge of pharmacokinetics and drug absorption with this quiz. Explore different routes of drug administration, including intranasal, intrathecal, topical, and transdermal, and learn about the processes of drug absorption, such as simple diffusion, facilitated diffusion, and active transport. Understand the factors influencing drug absorption, including pH, blood flow, and surface area.