Oxytetracycline is a tetracycline antibiotic, an alkaline, broad-spectrum antibiotic produced directly by Streptomyces. It works by inhibiting the synthesis of bacterial proteins, thus preventing the growth and reproduction of bacteria. Oxytetracycline hydrochloride is the salt form of oxytetracycline in which the drug molecule is bound to hydrochloric acid. This form is often used in pharmaceutical preparations because it is more stable and soluble in water compared to oxytetracycline. The hydrochloride form is commonly used for oral administration to treat a variety of bacterial infections, such as respiratory tract infections, urinary tract infections, acne, and certain sexually transmitted diseases.
Both forms of oxytetracycline are effective antibiotics, but the choice between them depends on factors such as route of administration, formulation requirements, and intended use.
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| CAS NO. | Product Name | Inquiry |
| 79-57-2 | Oxytetracycline | Inquiry |
| 2058-46-0 | Oxytetracycline hydrochloride | Inquiry |
| 6153-64-6 | Oxytetracycline dihydrate | Inquiry |
| 7179-50-2 | Oxytetracycline calcium | Inquiry |
The turbidimetric method is characterized by sensitivity and rapidity and can be used for the determination of the potency of hygromycin hydrochloride injection. The turbidimetric method utilizes Staphylococcus aureus as the experimental bacterium and evaluates the antimicrobial activity of hygromycin hydrochloride by determining the turbidity of the bacterial fluid after incubation for a certain period. The turbidity of the bacterial fluid is related to the growth of the strain and the concentration of the antibiotic, the higher the concentration, the more turbid the bacterial fluid.
Preparation of Reagents and Equipment
Oxytetracycline hydrochloride standard, Staphylococcus aureus strain, antibiotic medium III, phosphate buffer solution (pH 6.0), microbial turbidimetric tester, multifunctional microbial automatic measurement analyzer, electronic analytical balance, water-isolated electrothermal constant-temperature incubator and so on.
Experimental Procedures
1. Preparation of culture medium.
Take nutrient agar culture of Staphylococcus aureus, inoculate it on nutrient agar slant, and place it at 35 ℃ for 20 hours. Wash down the bacterial moss with sterilized physiological sodium chloride solution and dilute it with physiological sodium chloride solution to make its absorbance at 580 nm wavelength 1.0. Take 0.2 mL of bacterial solution and add it to 100 mL of antibiotic medium III, shake well to get the bacterial-containing medium.
2. Preparation of standard solution.
Weigh the appropriate amount of oxytetracycline hydrochloride standard, put it in a 50 mL measuring flask, add 0.1 mol/L hydrochloric acid solution 5mL to dissolve it, and then make it into a solution of 1000 u/mL with sterilized water as a reserve solution. Before use, dilute with phosphate buffer solution (pH 6.0) to the test concentration.
3. Preparation of test solution.
Measure 5 mL of oxytetracycline hydrochloride injection into a 250 mL flask, and make a solution of 1000 u/mL with sterilized water as reserve solution. The rest of the dilution steps are the same as the standard solution.
4. Linearity test.
Take an appropriate amount of standard stock solution, and dilute it into different concentrations with phosphate buffer (pH 6.0) according to the dose-to-pitch ratio of 1:1.5. Add each concentration of the solution into the medium containing bacteria, so that the final concentration range is 0.05-0.25 u/mL. 1.0 mL of each concentration of the solution, add 9.0 mL of the medium containing bacteria and place it in the tester according to the Latin square arrangement.
5. Determination of turbidity.
According to the growth of the experimental strains, the incubator was kept at a constant temperature of 37±0.5 ℃, and the turbidity of the bacterial solution was determined using a microbial turbidimetry tester after 3 to 4 hours of incubation. The turbidity values were recorded and the linear relationship between concentration and turbidity was statistically determined.
6. Data Processing.
The potency of oxytetracycline hydrochloride injection was calculated based on the linear relationship, including the recovery, correlation coefficient, and relative standard deviation (RSD).
