What Is the Difference Between PK and BE in Clinical Research?

PK and BE stand for pharmacokinetics and bio equivalent, respectively. The former is pharmacokinetics, which mainly refers to the drug concentration change with time in blood. While BE is bioequivalence, it is generally called so when the drug effects of two drugs in an organism are consistent, and the index usually adopts PK index, which is the Cmax and AUC drug concentration curve in the blood, falling between 80 and 125. Of course, sometimes BE is judged by dissolution curve or other pharmacodynamic indicators.

Generally, BE uses absolute bioavailability or relative bioavailability, while PK mainly collects blood/urinary drug concentration to obtain pharmacokinetic parameters (such as half-life, peak concentration, Peak time, clearance rate, apparent distribution, bioavailability, etc.). Pharmacokinetics collects data by different doses, drug cycles, genders, races, health groups, drug administration etc.; while bioequivalence is expressed using pharmacokinetic parameters – the area under the curve (AUC), peak concentration (Cmax).

The purpose of the experimental design between the two is different, in terms of generic drugs or modified dosage forms. Therefore, there are generally two preparations for BE, one is the reference preparation, the other is the self-developed preparation, to compare their relative bioavailability or absolute bioavailability and determine whether the drug is equivalent.

According to the current registration requirements, PK and BE are required to carry out (I take chemical drugs as an example):

1. PK: mainly for chemical drugs Class 1/2/3, except 1.6 and 3.4. It is divided into single-dose, low-medium-high three-dose group and multiple doses. For Class 5, controlled release formulations, a comparative study of pharmacokinetics is required.

2. BE: BE studies are required for Class 5 and 6 for oral preparations.

For details on how to implement PK and BE, please refer to these two guiding principles.

People in this field call it pharmacodynamics or Pharmacokinetics. Now pharmacokinetics has become an independent course; people in my department like to call it DMPK (the full name is Drug Metabolism and Pharmacokinetics).

The traditional and classic definition of Pharmacokinetics refers to the establishment of dynamic functions or model equations with mathematical method, which describes the disposition process after drugs entering the body. Pharmacokinetics is actually a synthetic vocabulary. The two parts of the roots represent “drugs” and “kinetics”. Together, they can be called pharmacokinetics. It is universally accepted that mathematical methods and model equations are the foundations of Pharmacokinetics.

Traditional Pharmacokinetics have not developed as the statistical Moment and compartmental analysis are mature, while its mathematical meaning is still developing rapidly. The most intuitive reflection is the pharmacokinetics (PK) – pharmacodynamics (PD) modelling and Population pharmacokinetics. Even the two branches of pharmacokinetics, combined with the use of some other pharmacy mathematical methods, gave birth to an emerging marginal discipline, Pharmacometrices.

Source by Dynah Lopez

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