Bioavailability Research

Bioavailability: refers to the degree and speed of the release of active pharmaceutical ingredients from the preparation into the systemic circulation. Generally divided into absolute bioavailability and relative bioavailability. Absolute bioavailability is the relative amount of pharmacologically active ingredients absorbed into the body by intravenous preparations (usually considered as 100% bioavailability of intravenous preparations) as a reference preparation; relative bioavailability is given by other non-intravenous routes The relative preparations (such as tablets and oral solutions) are the relative amounts of the active pharmaceutical ingredients obtained from the reference preparations absorbed into the systemic circulation.

Consistency evaluation service content of Medicilon
(1) A comprehensive comparison of the quality of self-made products and original research products

● Comparison of four dissolution curves

● Stability comparison: related substances, content, polymers, isomers, etc.

● Influencing factors: dissolution, related substances, content, polymers, isomers, etc.

● Long-term and accelerated conditions

(2) Improvement of prescription process

● Prescription optimization

● Process improvement

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Email: marketing@medicilon.com
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The above is about the content of the consistency evaluation of generic drugs. For details, please click the consistency evaluation.

Bioavailability (Bioavailability BA) is an index that reflects the degree and speed of absorption of active ingredients of the drug into the body. In the past, some adverse events due to the different bioavailability of the preparations have made people realize that it is necessary to verify the consistency or reproducibility of the bioavailability of the active ingredients in the preparations, especially those containing the same active ingredients. When a generic product replaces its original preparation and enters clinical use. In view of the correlation between drug concentration and therapeutic effect, assuming that the same blood drug concentration-time curve in the same subject means that the same drug concentration can be achieved at the site of action and produce the same therapeutic effect, then the pharmacokinetic parameters can be used as Substitute endpoint indicators to establish equivalence, that is, bioequivalence (Bioequivalence BE).
BA and BE research has become an important method to evaluate the quality of preparations. This guiding principle will focus on explaining the relevant concepts of BA and BE research, the scope of application, and the design, operation, and evaluation of BA and BE research.

If two drugs containing the same active substance are pharmacologically equivalent or pharmacologically replaceable, and their bioavailability (speed and degree) falls within predetermined acceptable limits after they are administered at the same molar dose, then it is considered Bioequivalent. These limits are set to ensure that the in vivo behavior of drugs in different preparations is equivalent, that is, the two preparations have similar safety and effectiveness.

Both BA (bioavailability) and BE (bioequivalence) are important indicators for evaluating the quality of the preparation. BA emphasizes the relative amount and speed of the active ingredients of the drug to reach the circulation in the body. One of the important basis of medication regimen (such as dosage and interval). The focus of BE is to compare with pre-determined equivalent standards and limits. It is the basis for ensuring the consistency of the behavior of different preparations containing the same pharmaceutical active ingredient in vivo, and the basis for judging whether the developed product can replace the use of the marketed drug.

BA and BE research have different roles in different stages of drug development:
In the new drug research stage, in order to determine the rationality of the new drug prescription and process, it is usually necessary to compare whether the preparation can achieve the expected bioavailability after changing the above factors; a new dosage form has been developed, and the bioavailability study of the proposed dosage form should be conducted to determine the dosage form. Reasonable, the BA dosage to be compared with the original dosage form to determine the dosage of the new dosage form, and the BE research can also be used to confirm whether the new dosage form is equivalent to the original dosage form; during the clinical trial, the BE study can be used to verify the same drug The consistency of products in different periods of time, such as: early and late clinical trial drugs, clinical trial drugs (especially the test drugs used to determine the dose) and drugs to be marketed.
In the production of generic drugs with existing national standards, BE research can be used to prove whether the generic products and the original drugs are bioequivalent and can be used interchangeably with the original drugs. After the drug is approved for marketing, if there is a certain degree of change in the composition of the prescription, the proportion and the process, the researcher needs to determine whether to conduct a BE study based on the degree of product change to investigate whether the product is bioequivalent after and before the change . New formulations developed for the purpose of improving bioavailability require BA studies to understand the changes in bioavailability before and after changes.

Related Articles:

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Drug Bioavailability Studies from Medicilon