Standard substance: In fact, it is a standard substance used in biological assays, antibiotics or biological drugs, and it is indicated by the titer unit "u".
The national drug reference substance and standard product series are mainly used to distinguish the content detection, impurities and related substances in the drug standard. It is an important component of the national drug standard. The national drug substance standard is an important foundation of the national drug standard. A measuring tool used to check the quality of drugs is the basis for measuring the quality of drugs. It is to revise the material standards of inspection equipment and methods; it can confess the authenticity and quality of medicines.
There are 1242 kinds of national drug standard substances recognized in our country. Among them, there are 288 kinds of Chinese medicine chemical reference materials and 400 kinds of reference medicinal materials. Potency) The measured standard materials, production equipment and calibration should meet the requirements of "National Standard Material Equipment and Calibration Regulations for Biological Products".
In the literature, the two concepts of standard and reference are often turbid, thinking that the reference is the standard. The reason for the turbidity is that some drugs have both reference and standard. For example, the determination of cephalosporin by microbiological method Cefaclor standard is used for the titer of cefaclor, and the reference substance is used for the determination by HPLC or UV method; when phenacetin is used as a melting point calibration substance, the melting point standard is used, and when the content is determined, the reference substance is used . In this case, there will be a standard substance and a reference substance for the same substance, but their standards, calibration methods and uses are different.
In practice, there is a mixed use of drug standards and reference products, that is, the content of the reference product or standard product is not the content of its calibration method. Although the contents of different calibrations of the same batch of reference substances have good correlation, they are not completely the same, and the differences are sometimes large. For example, the cefuroxime axetil reference substance supplied by Glaxo in the United Kingdom has a HPLC calibration of 96.9% for the content determination. Use; UV is 98.8%, for dissolution determination.
The reasons for mixed use are as follows:
1. It is extremely difficult to find the corresponding reference substance in daily scientific research;
2. The instruction manuals for reference materials provided by the Ministry of Health are not informative, and most of them have no reference quality requirements and calibration methods;
3. Lack of knowledge about the correct use of reference or standard products;