Biopharmaceutics is the study of how the physical and chemical properties of drugs and their dosage forms affect the drug's absorption, distribution, metabolism, and excretion.
Why is bioavailability important in biopharmaceutics?
Bioavailability refers to the extent and rate at which the active drug ingredient is absorbed and becomes available at the site of action.
What role does solubility play in biopharmaceutics?
Solubility affects a drug's absorption rate; poor solubility can lead to inadequate drug concentrations in the bloodstream irrespective of dosage increases.
How does particle size influence drug absorption?
Smaller particles have a larger surface area to volume ratio, enhancing dissolution and thus increasing the absorption rate.
What is the significance of the first-pass effect?
The first-pass effect refers to the reduction in bioavailability of a drug as it passes through the liver where it is metabolized before reaching systemic circulation.
Describe the difference between immediate-release and controlled-release formulations.
Immediate-release formulations dissolve quickly, releasing the active drug immediately, whereas controlled-release formulations release the drug over a prolonged period.
How does pH affect drug absorption?
The pH of the surrounding environment can affect the ionization state of a drug, influencing its solubility and permeability through biological membranes.
What factors influence drug distribution within the body?
Drug distribution is affected by factors such as blood flow to tissues, drug affinity to tissue proteins, and the presence of barriers (e.g., blood-brain barrier).
Define 'therapeutic window' in the context of biopharmaceutics.
The therapeutic window is the range of drug dosages which can treat disease effectively while staying within the safety limit (below the threshold of toxicity).
What is 'drug half-life' and why is it important?
The drug half-life is the time required for the concentration of the drug in the bloodstream to decrease by half, essential for determining dosing frequency.
How do prodrugs differ from active drugs in biopharmaceutics?
Prodrugs are inactive compounds that convert into an active form within the body, enhancing bioavailability and targeted delivery.
Discuss the impact of drug-food interactions.
Food can affect drug absorption, leading to either increased or decreased drug bioavailability due to changes in gastric pH, motility, or enzyme activity.
What is therapeutic drug monitoring (TDM)?
TDM is the clinical practice of measuring drug levels in the blood at designated intervals to maintain a drug’s therapeutic effects without causing toxicity.
How does genetic variability affect drug metabolism?
Genetic variability can lead to differences in enzyme activity involved in drug metabolism, resulting in variations in drug efficacy and safety among individuals.
Explain the concept of 'bioequivalence'.
Bioequivalence means that two drug products release their active ingredients into the bloodstream at the same rate and extent.