Analysis of the advantages and disadvantages of the selection of special bacteriostatic agents for diagnostic reagents
The stability of in vitro diagnostic reagents is the key to restrict the marketization and internationalization of products, and the stability of reagents is closely related to the bacteriostatic system.
The stability of diagnostic reagents involves three aspects. First, whether the reagents have a sufficient validity period. The reagents often contain serum, enzymes, substrates and antigen-antibodies, which are easy to breed bacteria and molds. An imperfect bacteriostatic system will greatly shorten the validity period. And affect the linearity, sensitivity, precision and accuracy of the reagents; second: the stability of the machine and the stability of the bottle opening, the diagnostic reagents need to be used in conjunction with the instrument for a period of time, can it be guaranteed to be on the machine within 15 to 60 days Stability is the key; third: the mutual influence of the environment, the abuse of drugs in the hospital and inappropriate cleaning and disinfection methods have caused many drug-resistant strains, the pipelines of instruments, reagent needles, sample needles, etc. are seriously polluted, and the pipelines and sampling institutions are in contact with each other. Contamination caused by reagents is particularly common, and bacterial contamination in the pipeline leads to good and bad test results. A good antibacterial system is the beginning of ensuring the quality of reagents.
With the continuous development of domestic in vitro diagnostic reagents, the requirements for preservatives are getting higher and higher, and preservatives that are harmful to the human body and the environment, such as thimerosal and sodium azide, will be gradually replaced. In the future, preservatives will develop in the direction of broad spectrum, high efficiency, low toxicity and environmental protection. The criteria for selecting and judging suitable bacteriostatic agents for in vitro diagnostic reagents are as follows: 1. Broad-spectrum sterilization, which can effectively inhibit bacteria (including gram-positive and gram-negative bacteria), molds, yeasts and other microorganisms; 2. Fast and long-lasting It can kill all kinds of microorganisms; 3. It can be stable and effective in a wide pH range; 4. It has excellent physical and chemical compatibility, will not affect the activity of the enzyme, will not affect the binding of antigen and antibody, and will not cause the reagent to change color; 5. Good water solubility, easy to use; 6. Low toxicity under the recommended dosage, no adverse effect on the environment, and biodegradable.
1. Sodium azide ---- highly toxic, has inhibitory effect on HRP;
2. Thimerosal ---- Metal mercury has biological toxicity risks and has been gradually phased out
3. Antibiotics - easy to produce drug resistance, more early use, has been gradually eliminated
4. Cationics--change the permeability of cell membranes to achieve bactericidal effect,
5. Formaldehyde release body - is cell protein denaturation, rapid sterilization, such as methyl urea
6. Isothiazolinones--obvious bactericidal effect on bacteria and fungi, especially no interference with enzymes in the formula, suitable for pH<9.5 conditions, sensitive to sulfhydryl and -NH2;
7. Alcohols----------change the permeability of cell membranes, such as phenoxyethanol, etc., which have good compatibility with formulas and are often used in daily chemical personal care products.
