Importance of bioavailability in the bioequivalence

At present, the quality of clinical trials is becoming increasingly important in the public action sense. Relating to their growing importance, the cost of this kind of research is steadily growing. However, not all companies are able to produce original drugs, and not every consumer can afford them, which is why their quality substitutes are needed — generic. To comply with all standards, it is necessary to conduct a bioequivalence study.

According to the definition of WHO, two drugs are considered bioequivalent, if they are pharmaceutically equivalent, have the same bioavailability and when used in the same dose ensure proper efficacy and safety. In one of the previous articles, we have already discovered the concept of bioequivalence. However, in this definition, there is another important term — bioavailability. It is about bioavailability that will be discussed in this article.

So, bioavailability is the proportion of the administered dose of an unchanged medical product that enters the bloodstream (the circulatory system). Bioavailability can be either low or high. When injecting directly into the bloodstream, for example, intravenous injection, bioavailability is defined as 100%. Low bioavailability is most typical for oral dosage forms of water-soluble and slowly absorbed drugs.

The degree of bioavailability is influenced by such indicators as:

  • Age;
  • Sex;
  • Physical activity;
  • Genotype;
  • Stress;
  • Various disorders and/or transferred operations of the digestive tract

Absolute and relative bioavailability is also distinguished. Absolute bioavailability compares the bioavailability of active pharmaceutical ingredients (APIs) in the circulatory system after administration by an intravenous route with bioavailability of the same medication when administered intravenously. This is the percentage of APIs absorbed because of non-intravenous administration, compared with the corresponding medication administered intravenously. In short, in the case of absolute bioavailability, the intravenous administration will be the standard.

The relative bioavailability characterizes the bioavailability of the dosage form (A) of a particular medical product when compared with another dosage form (B) of the same drug and is usually the established standard for cases of non-intravenous administration when the administration is via any other channel. In studies of bioequivalence, depending on the goals, both absolute and relative bioavailability indicators are considered.

From all the above, it is obvious that it is impossible to carry out pharmacokinetic studies (bioequivalence studies) without adequate knowledge of bioavailability. X7 Research understands the complexity of this kind of trial and considers all the above indicators when working on specific projects. You can be assured of the quality of our services and the professionalism of our employees.

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Source: EUPATI.