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What are the main research contents of the local toxicity test?

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The test designed to study the toxicity caused by topical medication is a local toxicity test, which is an important part of toxicology research, including irritation test, allergic test, hemolysis and skin toxicity test. Generally speaking, ointments, drops, lotions, scalp patches, sprays, powders for external use and other dosage forms must be  tested for local toxicity of drugs. Allergy test, irritation test, hemolytic test and skin toxicity test are the research contents of local toxicity test.


1.Allergy test

The allergic test observes the systemic or local allergic reactions of animals after injection and administration. Allergic reactions are divided into 4 types, including the immediate type mediated by immunoglobulin E (IgE), the cytotoxic type or the cytolytic type mediated by IgG Type, immune complex type or vasculitis type mediated by IgG and IgM, and delayed type or type mediated by T lymphocytes. In order to explore and establish a rat-type allergy test method based on the detection of blood biomarkers, some researchers first developed a rat systemic allergic reaction symptom table and sensitization evaluation criteria, then tested the serum indicators of sensitized rats, and then observed The symptoms of allergic reaction in rats after challenge and so on. Finally, it was found that the serum IgE level after sensitization in the rat allergy test method is highly correlated with the symptoms of allergic reaction, which can be used as a blood biomarker to evaluate the sensitization of the tested drug.

Allergy is the most common and most serious adverse reaction of injections. What kind of allergy test should be determined according to the characteristics of the drug, clinical indications, mode of administration, mechanism and influencing factors, etc.

2. Irritation test

The irritation test mainly observes whether the blood vessels, muscles, skin and other parts of the animals cause inflammatory lesions such as redness, congestion, exudation, degeneration, or necrosis when administered according to the clinically intended route. At the same time, observe the general state of the animal. Conduct a comprehensive evaluation of local and overall behaviors, physical signs, etc. For example, the acute eye irritation test aims to confirm and evaluate whether the test product has irritation or corrosive effect on the eyes of mammals and its degree, so as to provide a basis for safety protection during production and use. Skin irritation refers to the local reversible damage caused by the skin contacting the test substance. It has always been used to predict the irritation of the test substance to human skin through animal experiments. Skin irritation is primary, allergic, painful, etc. 3 types. In toxicology research, irritation tests should be combined with the specific conditions of the species and the specific problems found in the research, and reasonable methods should be adopted to provide more valuable test results and improve the clinical predictability of the test.

Pharmaceutical toxicology research is a science based on the physical and chemical properties of drugs, using the principles and methods of toxicology, to conduct a comprehensive and systematic safety evaluation of drugs and to clarify their toxic mechanism, so as to reduce the degree of harm to human health by drugs. Medicilon is an outsourcing company engaged in pharmaceutical research and development, with professional knowledge in drug metabolism, pharmacokinetics, pharmacodynamic research, and toxicology. Provide customers with high-quality data and fast turnaround to support various drug development, preclinical research and clinical research.

3. Hemolysis test

Some medicines have toxic side effects that cause changes in red blood cell membranes, and even rupture red blood cells, which can be life-threatening in severe cases. For example, injections made of Chinese herbal medicine often contain saponins, which can rupture and dissolve red blood cells, resulting in hemolysis. Therefore, through the observation of hemolysis test, the safety of certain Chinese herbal medicine preparations, especially medicines for intravenous injection, can be determined. The purpose of the hemolytic test is to observe whether the test substance can cause hemolysis and red blood cell aggregation, including in vivo/in vitro hemolysis test.

4. Skin toxicity test

The skin drug toxicity test is to observe the toxic reaction of the intact and broken skin of animals in short-term contact with the test substance. The principle of the experiment is that when the skin contacts the test substance, the irritating substance contained in the test substance stimulates the nerve endings of the skin and expands the blood vessels. , Exudate and produce corresponding reversible inflammatory reaction. Record points according to the strength of the reaction, and evaluate the stimulus intensity of the test substance.

The main focus of drug research and development is effectiveness and safety. Through toxicological research, safety windows, toxic target organs, and adverse reactions can be discovered, providing data for predicting human adverse reactions.

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