Adopting methods such as one dose method (standard curve method), two dose method, and three dose method. Generally, the determination of linearity and range is carried out using the one dose method (standard curve method), the conventional content determination is carried out using the two dose method, and the standard calibration is carried out using the three dose method. Measure the diameter of each inhibition zone and obtain the average diameter of the inhibition zone caused by the dilution of the standard solution and the sample solution. After obtaining the correction value according to the standard preparation method, the sample solution is

Correct the average diameter of the antibacterial zone, obtain the potency of the sample solution, and convert it into the number of units per milligram of the tested sample.

Antibiotics are physiologically active substances that are sensitive to life phenomena, and their potency can be expressed by their biological efficacy. The smallest potency unit of antibiotics is calledUnit "(U). The standard unit established through international consultation is called the "International Unit" (IU), which is usually used to measure the active ingredients of various antibiotics based on national antibiotic standards. Both chemically synthesized and semi synthesized antibiotics are expressed by weight, while biosynthetic antibiotics are expressed by potency, and the weight corresponding to the potency is also indicated. Potency is measured by antibacterial efficacy (active part), therefore, the relative standard for measuring the quality of antibiotics is the level of potency.