Intestinal absorption After ingestion of a drug, the active ingredient must first be released. This process is called release (liberation), and it is a prerequisite for subsequent absorption. Absorption (formerly: resorption) is the passage of an active pharmaceutical ingredient from the digestive pulp into the bloodstream in the stomach and intestines. Absorption occurs primarily in … Absorption
Definition Accumulation refers to the accumulation of an active pharmaceutical ingredient in the organism during regular drug administration. The term comes from the Latin (to accumulate). It occurs when there is an imbalance between the intake and elimination of the active ingredient. If the dosing interval is too short, too much drug is administered. If … Cumulation
Pharmacodynamics and pharmacokinetics. When we take a tablet, we are usually interested in its immediate effects. The drug is supposed to relieve a headache or reduce symptoms of a cold. At the same time, we may think about the possible side effects it may trigger. The desired and undesired effects that a drug exerts on … ADME
Definition and mechanisms A pharmacokinetic booster is an agent that improves the pharmacokinetic properties of another agent. It is a desirable drug interaction It can exert its effects at different levels (ADME): Absorption (uptake into the body). Distribution (distribution) Metabolism and first-pass metabolism (metabolization). Elimination (excretion) Pharmacokinetic enhancers can increase absorption, increase distribution to an … Pharmacokinetic Booster
Introduction Elimination is a pharmacokinetic process that describes the irreversible removal of active pharmaceutical ingredients from the body. It is composed of biotransformation (metabolism) and excretion (elimination). The most important organs for excretion are the kidney and the liver. However, drugs can also be excreted through the respiratory tract, hair, saliva, milk, tears, and sweat. … Elimination
Introductory question How much active ingredient is in a 10 mg cetirizine tablet? (a) 5 mg B) 7.5 mg C) 10 mg The correct answer is a. Image and mirror image Many active pharmaceutical ingredients exist as racemates. They consist of two molecules that behave like an image and mirror image of each other. These … Enantiomers
The effect of the first liver passage For a perorally administered pharmaceutical agent to exert its effects at the site of action, it usually must enter the systemic circulation. To do so, it must pass through the intestinal wall, the liver, and part of the circulatory system. Despite complete absorption in the intestine, the bioavailability … First-Pass Metabolism
Introduction Biotransformation is an endogenous pharmacokinetic process that leads to a change in the chemical structure of active pharmaceutical ingredients. The organism’s general goal in doing so is to make the foreign substances more hydrophilic and to direct them to excretion via the urine or stool. Otherwise, they could be deposited in the body and … Metabolism (Biotransformation)
Definition When two or more drugs are combined, they may affect each other. This is especially true with regard to their pharmacokinetics (ADME) and effects and adverse effects (pharmacodynamics). This phenomenon is called interaction and drug-drug interaction. Interactions are usually undesirable because they can lead to, for example, loss of efficacy, side effects, poisoning, hospitalization, … Interactions
Definition and properties When active pharmaceutical ingredients enter the bloodstream, they often bind to proteins, especially albumin, to a greater or lesser extent. This phenomenon is called protein binding, and it is reversible: drug + protein ⇌ drug-protein complex Protein binding is important, first, because only the free portion distributes to tissues and induces a … Protein Binding
Definition and examples When a drug is administered, for example, a tablet is swallowed or an injection is injected into a vein, the active pharmaceutical ingredients subsequently spread throughout the body. This process is called distribution. Active ingredients distribute throughout the bloodstream, into tissues, and are eliminated through metabolism and excretion. Mathematically, the volume of … Volume of Distribution
Definition Plasma concentration is the concentration of a pharmaceutical agent in blood plasma at a given time after administration. Plasma is the liquid portion of blood excluding its cellular components. Concentration is typically expressed in µg/ml. Plasma concentration-time curves If plasma levels are measured several times after administration, a plasma concentration-time curve can be constructed … Plasma Concentration
