Sterility is the complete absence of living microorganisms. For medicines, the presence of microbes, albeit in a small amount, can be fatal, since they can enter the blood and mucous epithelium of a person with low immunity. Therefore, in medicine, tests are carried out on the sterility of medicines and products, biological products using thioglycol medium.
Short description of the tool
Thioglycolic medium is a universal medium containing sodium thioglycolate and thioglycolic acid. It creates favorable conditions for the growth of bacteria, therefore, it is used to control the sterility of drugs, medical devices, vaccines and serums, allergens, etc.
The composition of the product includes components such as sodium thioglycolate, thioglycolic acid, sodium chloride, cysteine, dry peptone, microbiological agar, yeast extract, and others.
The drug is produced in the form of a powder, which is packaged in jars of 50, 100, 250 and 500 grams. It is diluted with water before use, a liquid thioglycol medium is obtained, which reduces redox processes and activates the growth of anaerobic microbes.
Instruction for use
To prepare the solution, it is necessary to take a powder in an amount of 30 grams, dilute in 1 dm³ of pure water, boil until the substance is completely dissolved. This usually takes about three minutes. Then the solution must be passed through a cotton filter. It is poured into test tubes with a capacity of 10 cm³, then sterilized in an autoclave for fifteen minutes at a temperature of one hundred twenty-one degrees and 1.1 atmospheres. After this, the solution is cooled to 25 degrees. Thioglycolic medium is ready.
If some of the solution turns pink on top, it can be restored only once. To do this, it is heated in a water bath or under a stream of steam until this color disappears.
How to store the drug
Store thioglycol medium 250 gr. or in a different dosage, it is necessary in hermetically sealed packaging. In this case, the air temperature should be from 5 to 25 degrees, and the air humidity should not exceed 60%. Shelf life is two years.
Sterility testing
Thioglycol medium is used to study sterility. The investigated material in the amount of 1 ml is inoculated into the liquid medium. If medicines are checked, then the crops are inhibited at a temperature of thirty-seven degrees for two days. One tube with medium is left inoculated to control the process.
After the incubation period, the crops are viewed daily. Sterility is assessed visually if microbes are present, the medium becomes cloudy, a film forms on it or a precipitate appears.
In the absence of growth of microorganisms, the studied material is considered to be sterile.
As you can see, the analysis is done quite simply. According to its results, the appropriateness of the use of drugs or medical devices in practice is assessed. Such a study makes it possible to prevent the entry of pathogenic microbes into the human body.