What are factors affecting bioequivalence?

What are factors affecting bioequivalence?

Factors which influence bioavailability

• Drug concentration at site of administration.
• Surface area of the absorptive site.
• Drug pKa.
• Drug molecule size.
• pH of the surrounding fluid.

What is Cmax Tmax and AUC?

Abstract. The three classical pharmacokinetic parameters used to assess bioequivalence, AUC (total area from zero to infinity), Cmax (peak plasma concentration), and tmax (time to reach Cmax), are suitable to determine the extent and rate of absorption of immediate-release drug products.

What is Cmax and Tmax of drug?

Cmax is the opposite of Cmin, which is the minimum (or trough) concentration that a drug achieves after dosing. The related pharmacokinetic parameter tmax is the time at which the Cmax is observed.

What is Tmax pharmacokinetics?

tmax – the time take to reach Cmax. AUC (Area Under the Curve) – a measure of the exposure to the drug. t1/2 (elimination half-life) – the time taken for the plasma concentration to fall by half its original value (shown in. figure 3 using a semi-logarithmic plot of the elimination phase only) Bioavailability.

How is bioequivalence determined?

Bioequivalence is determined based on the relative bioavailability of the innovator medicine versus the generic medicine. It is measured by comparing the ratio of the pharmacokinetic variables for the innovator versus the generic medicine where equality is 1.

Why bioequivalence study is important?

Bioequivalence studies are very important for the development of a pharmaceutical preparation in the pharmaceutical industry. Their rationale is the monitoring of pharmacokinetic and pharmacodynamic parameters after the administration of tested drugs.

Which is more important Cmax or AUC?

Cmax is highly correlated with the area under the curve (AUC) contrasting blood concentration with time. Therefore, use of the Cmax/AUC ratio is recommended for assessing the equivalence of absorption rates.

What is are the importance of AUC as a pharmacokinetic parameter?

Toxicology AUC can be used as a measure of drug exposure. It is derived from drug concentration and time so it gives a measure how much – how long a drug stays in a body. Pharmacokinetics Drug AUC values can be used to determine other pharmacokinetic parameters, such as clearance or bioavailability, F.

What is the significance of Cmax?

A pharmacokinetic measure used to determine drug dosing. Cmax is the highest concentration of a drug in the blood, cerebrospinal fluid, or target organ after a dose is given.

What is AUC and Cmax?

Abstract. In bioequivalence studies, the maximum concentration (Cmax) is shown to reflect not only the rate but also the extent of absorption. Cmax is highly correlated with the area under the curve (AUC) contrasting blood concentration with time.

What is the bioequivalence limit for AUC and Cmax?

Limits of 80\%-125\% for AUC and 70\%-143\% for Cmax. What is the impact on bioequivalence studies? Without further scientific or clinical rationale, we find it difficult to justify widening the bioequivalence limit for Cmax to 70\%/143\% for either fasting or fed BE studies.

What is pharmacokinetic profile and minimum effective concentration?

The pharmacokinetic profile is how the drug concentration changes in time, and it depends on the drug half-life, route of administration and dosage form. The Minimum Effective Concentration is the lowest possible concentration of the drug in plasma that results in a therapeutical effect.

What is AUC (area under the time-concentration curve)?

AUC (area under the time-concentration curve) measures the “extent of drug absorption”. The definition of bioequivalance as described by FDA in brief is : The rate and extend of drug absorption of a generic medicine should be same (not significantly different) as the brand medicine under similar experimental conditions.