Pharmacology: Routes of Drug Administration and ADME Process

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the phenomenon known as 'first-pass metabolism'?

The rapid absorption of a drug through the digestive tract with minimal metabolism in the liver.

A process where a drug is administered orally, extensively metabolized in the liver, and has reduced bioavailability. (correct)

When a drug administered orally enters the liver and undergoes minimal biotransformation.

Extensive biotransformation of a drug in the liver leading to increased bioavailability.

Which route of drug administration bypasses both gastric and hepatic metabolism?

Intravenous (IV) (correct)

Sublingual

Topical

Rectal

Why is rectal administration considered suitable for patients who may be vomiting or unconscious?

Effective for prolonged drug release

Rapid absorption of drugs

Bypass of gastrointestinal metabolism

Stable environment with no enzymatic metabolism (correct)

Which type of drug delivery offers an 'instantaneous response'?

Intramuscular (IM) Signup and view all the answers

Which route of administration is known for requiring surfactants to enhance drug dissolution?

Intravenous (IV) Signup and view all the answers

What characterizes drugs administered via the buccal route?

Bypassing gastrointestinal metabolism Signup and view all the answers

Why is intramuscular (IM) administration often preferred for anticancer drugs?

Fast absorption compared to other routes Signup and view all the answers

What is the primary energy source for symporters in secondary active transport?

Electrochemical gradient Signup and view all the answers

Which type of drug absorption involves the engulfment of macromolecules to form vesicles?

Pinocytosis Signup and view all the answers

In pharmacokinetics, what factor influences the rate of reversible interaction between a drug and its carrier?

Rate of reversible interaction Signup and view all the answers

Which region of the gastrointestinal tract is known for being acidic and impacting drug absorption?

Stomach Signup and view all the answers

Which physicochemical property of drugs determines their absorption and excretion rates?

Log P octanol/water Signup and view all the answers

What is the main purpose of enteric-coating in oral drugs?

Protect the active ingredient in the stomach Signup and view all the answers

What is the main reason why polar (toxic) materials cannot enter cell membranes easily?

Tight junctions Signup and view all the answers

Which type of molecules can easily permeate lipid membranes due to their size and solubility characteristics?

Lipid-soluble and unionized molecules Signup and view all the answers

In pharmacokinetics, what is the term used to describe the quantitative measure of a substance's ability to dissolve in lipids?

Log P value Signup and view all the answers

What is the main factor that determines how well a substance can mix with oily phases in lipid diffusion?

Degree of ionization Signup and view all the answers

Which barrier allows for the passage of lipid-soluble and unionized drugs while preventing water-soluble substances?

Placenta barrier Signup and view all the answers

What type of transport mechanism ensures an easier passage for non-ionized drugs across membranes?

Lipid diffusion Signup and view all the answers

Study Notes

Drug Metabolism and Administration

First-pass metabolism refers to the initial metabolism of a drug by the liver after oral administration before it reaches systemic circulation.
Sublingual administration bypasses both gastric and hepatic metabolism, enabling rapid drug absorption directly into the bloodstream.

Administration Routes and Patient Conditions

Rectal administration is useful for patients who may be vomiting or unconscious, as it doesn’t require swallowing and provides an alternate route for medication absorption.
Intravenous (IV) drug delivery offers an instantaneous response, allowing for immediate drug effects.

Drug Solubility and Absorption

Oral administration may require surfactants to enhance drug dissolution, improving absorption in the gastrointestinal tract.
Drugs administered via the buccal route are characterized by their ability to dissolve directly in the mouth's mucous membranes, providing rapid absorption into systemic circulation.

Drug Delivery Preferences

Intramuscular (IM) administration is often preferred for anticancer drugs due to its ability to deliver larger volumes of medication and sustain absorption over time.

Transport Mechanisms

The primary energy source for symporters in secondary active transport is the sodium gradient, often established by primary active transport mechanisms.
Endocytosis is the process of drug absorption that involves the engulfment of macromolecules to form vesicles.

Pharmacokinetics Factors

In pharmacokinetics, the rate of reversible interaction between a drug and its carrier is influenced by factors such as the drug's affinity for the carrier and concentration gradients.
The gastric region of the gastrointestinal tract is known for its acidic environment, which can significantly impact the solubility and absorption of various drugs.

Physicochemical Properties

The lipophilicity of drugs plays a crucial role in determining their absorption and excretion rates, impacting how well drugs penetrate cell membranes.
Enteric-coating in oral drugs is primarily designed to protect the drug from degradation in the acidic stomach and to allow for release in more neutral intestinal pH.

Membrane Permeability

Polar (toxic) materials struggle to enter cell membranes easily due to their hydrophilic nature, which inhibits membrane permeability.
Non-polar molecules, due to their size and solubility characteristics, can easily permeate lipid membranes.

Diffusion and Transport Mechanisms

The partition coefficient refers to the quantitative measure of a substance's ability to dissolve in lipids, influencing its absorption.
The ability of a substance to mix with oily phases is primarily determined by its lipophilicity, impacting lipid diffusion.
Cell membranes act as a barrier that permits lipid-soluble and unionized drugs to pass while restricting water-soluble substances.
Passive diffusion mechanisms facilitate easier passage for non-ionized drugs across biological membranes, allowing for effective drug absorption.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

Learn about the process drugs go through in the body - from liberation to excretion, and the different routes of drug administration including local (topical, nasal, oral) and systemic (enteral, parenteral). Explore examples like bronchial dilators and clotrimazole troches.