Bioequivalence
The term bioequivalence comes from pharmacokinetics and evaluates the interchangeability of two drugs with the same active ingredients , but which differ in the manufacturing process and / or in the auxiliary substances they contain .
definition
Two drugs are called bioequivalent if the bioavailability corresponds to 80 to 125% within a 90% confidence interval . The extent and speed of drug absorption are compared. In the case of bioequivalent drugs, it is assumed that an exchange between the two drugs can take place without any risk to the patient. However, such an exchange is problematic in the case of drugs with a narrow therapeutic range . Theophylline , thyroxine or digitoxin are such drugs.
The bioequivalence test is carried out using a pharmacokinetic study on volunteers. Two groups receive the same dose of the test drug or the reference product under strictly standardized conditions. Blood samples are taken at certain time intervals and analyzed for the drug concentration.
Mathematical parameters based on which the bioequivalence can be judged are, for example, the area under the plasma concentration -time curve ( area under the curve (AUC) (see trapezoidal rule )) or the peak plasma levels (C max ). The time at which the peak plasma level occurs (t max ), the minimum plasma level (C min ) and the absorption delay time (t lag ) are further parameters .
In the case of referring drug approvals , which are usually applied for and granted for generics , the responsible authorities require the applicant to provide evidence of bioequivalence with the original product of the first supplier. The 90% confidence interval ( confidence interval ) of the quotient of the average values determined for the parameters to be compared for the test product and reference product must be within clearly defined limits (80–125% are usual). The selection of the parameters and the study design depend, among other things, on the indication and the dosage form of the drug.
Web links
- ADHDpedia - bioequivalence