Introduction to Biopharmaceutics
This discipline studies how the physicochemical properties of a drug and drug product influence bioavailability in vivo.
What is biopharmaceutics?
This process is defined as the passage of a drug from its site of administration into the plasma.
What is drug absorption?
This term is defined as the rate and extent to which the active ingredient is absorbed from a drug product and becomes available at the site of drug action.
What is bioavailability?
This type of study compares the in-vivo bioavailability of a test drug product to a reference listed drug.
What is a bioequivalence study?
These drug products are formulated to release the active drug immediately after oral administration, with no deliberate effort to modify the release rate.
What are immediate-release (IR) drug products?
Biopharmaceutics is the interrelationship between the physicochemical properties of the drug, the dosage form (drug product), and this factor, all influencing the bioavailability of the drug.
What is the route of administration?
Before absorption can occur, an orally administered solid drug must first undergo this process to enter an aqueous solution.
What is dissolution?
These are the two main types of bioavailability described for drug products.
What are absolute bioavailability and relative bioavailability?
Bioequivalence studies are considered this type of bioavailability study.
What is a relative bioavailability study?
These drug products alter the timing and/or the rate of release of the drug substance compared with conventional products.
What are modified-release (MR) drug products?
This term is defined as the release of the drug substance from the drug product either for local drug action or for systemic therapeutic activity.
What is drug product performance?
This region of the gastrointestinal tract is the primary site of drug absorption due to its large surface area and extensive blood supply.
What is the small intestine?
This type of bioavailability compares the availability of a drug product to another dosage form or product of the same drug given at the same dose and by the same route.
What is relative bioavailability?
This study design is most commonly used in bioequivalence testing, where each subject receives both the test and reference products.
What is a two-way crossover study?
The primary objective of modified-release drug products is to achieve this therapeutic outcome.
What is a prolonged therapeutic effect with reduced fluctuation in plasma drug concentrations?
Design of the drug product, stability of the drug within the drug product, manufacture of the drug product, release of the drug from the drug product, rate of drug dissolution at the absorption site, and delivery of drug to the site of action are all examples of these.
What are factors influencing biopharmaceutics?
Increased gastric emptying time will generally have this effect on the absorption of most orally administered drugs.
What is increased absorption?
This pharmacokinetic measure reflects the overall extent of drug absorption into the systemic circulation.
What is the area under the plasma concentration–time curve (AUC)?
Bioequivalence is established when the 90% confidence intervals for these two pharmacokinetic parameters fall within 80% to 125%.
What are Cmax and AUC?
Ideally, extended-release drug products should release the drug at this kinetic rate in order to maintain relatively constant plasma drug concentrations.
What is zero-order release?
In a sequence of drug absorption processes, this term describes the slowest step that controls the overall rate of absorption.
What is the rate-limiting step?
This transport mechanism allows highly ionized drugs to be absorbed by forming a neutral complex with an oppositely charged ion.
What is ion-pair transport?
Plasma drug concentration studies assume a direct relationship between drug concentration in plasma and drug concentration at this location.
What is the site of drug action?
This regulatory term refers to the brand-name drug product that serves as the reference for approval of a generic drug product.
What is the Reference Listed Drug (RLD)?
This phenomenon is defined as the release of more than the intended fraction of drug, or release at a faster rate than intended, potentially leading to adverse plasma drug concentrations.
What is dose dumping?