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GB/T 15670 consists of the following parts under the general title Toxicological test methods for pesticides registration:
——Part 1: General principles;
——Part 2: Acute oral toxicity test - Horn's method;
——Part 3: Acute oral toxicity test - Up-and-down-procedure;
——Part 4: Acute oral toxicity test - Up-and-down-procedure;
——Part 5: Acute dermal toxicity test;
——Part 6: Acute inhalation toxicity test;
——Part 7: Dermal irritation/corrosion test;
——Part 8: Acute eye irritation/corrosion test;
——Part 9: Skin sensitisation test;
——Part 10: Short-term repeated dose 28-day oral toxicity study;
——Part 11: Short-term repeated dose 28-day dermal toxicity study;
——Part 12: Short-term repeated dose 28-day inhalation toxicity study;
——Part 13: Subchronic toxicity study;
——Part 14: Bacterial reverse mutation test;
——Part 15: In vivo mammalian bone marrow polychromatic erythrocyte micronucleus test;
——Part 16: In vivo mammalian bone marrow cell chromosome aberration test;
——Part 17: Mammalian spermatogonial/spermatocyte chromosome aberration test;
——Part 18: Rodent dominant lethal test;
——Part 19: In vitro mammalian cells chromosome aberration test;
——Part 20: In vitro mammalian cell gene mutation test;
——Part 21: Unscheduled DNA synthesis (UDS) test with mammalian liver cells in vivo;
——Part 22: DNA damage and repair/unscheduled DNA synthesis test in mammalian cells in vivo;
——Part 23: Teratogenicity study;
——Part 24:Two-generation reproduction toxicity study;
——Part 25: Acute delayed neurotoxicity test;
——Part 26: Chronic toxicity study;
——Part 27: Carcinogenicity study;
——Part 28: Combined chronic toxicity/carcinogenicity study;
——Part 29: Metabolism and toxicokinetics study.
This part is Part 12 of GB/T 15670.
This part is developed in accordance with the rules given in GB/T 1.1-2009.
This part replaces GB/T 15670-1995 Toxicological test methods of pesticides for registration partly.
The following main changes have been made with respect to the part of subacute inhalation toxicity test in GB/T 15670-1995:
——This part is renamed as Short-term repeated dose 28-day inhalation toxicity study;
——The overall structure and format are modified and adjusted;
——Some clauses and subclauses are added or refined (Clauses 1, 2, 3 and 5, 6.1.1, 6.1.2, 6.1.3, 6.1.4, and Clauses 7 and 8);
——The requirements for laboratory animals are modified (see 6.1.5; 10.3 of Edition 1995);
——In the description of the implementation of repeated inhalation exposure, the exposure time is modified to: "unless otherwise specified, inhalation exposure generally is carried out for 28d continuously, with 6h every day and 7d every week. In consideration of the actual work conditions, it is also possible to carry out inhalation exposure for 5d every week" (see 6.2.1.2; 10.6 of Edition 1995).
This part was proposed by and is under the jurisdiction of the Ministry of Agriculture of the People's Republic of China.
The previous edition of this part is as follows:
——GB/T 15670-1995.
Toxicological test methods for pesticides registration -
Part 12: Short-term repeated dose 28-day inhalation toxicity study
1 Scope
This part of GB/T 15670 specifies the basic principles, methods and requirements of short-term repeated dose 28-day inhalation toxicity study.
This part is applicable to short-term repeated dose 28-day inhalation toxicity study performed for pesticides registration.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB 14925 Laboratory animal - Requirements of environment and housing facilities
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
short-term repeated dose inhalation toxicity
adverse health effect caused by repeated inhalation of the test object for a period less than 10% of the life of laboratory animal
3.2
inhaled dose
the amount of test object inhaled per unit body weight of animal, i.e.:
(1)
where,
Dih——the inhaled dose, mg/kg;
c——the concentration of the test object in the inhaled gas, mg/L;
t——the inhalation duration, min;
R——the respiratory rate, times/min;
Tv——the tidal volume of the tested animal, L/time;
α——the retention coefficient related to the reactivity and solubility of the test object;
W——the body weight, kg.
3.3
no observed adverse effect level; NOAEL
the highest dose or concentration of the test object with no exposure-related adverse effect observed with the existing technical means or test indexes under the specified test conditions
3.4
lowest observed adverse effect level; LOAEL
the lowest dose or concentration of the test object with exposure-related adverse effect observed with the existing technical means or test indexes under the specified test conditions
3.5
cumulative toxicity
adverse reaction caused by repeated exposure, which is the result of the continuation of the effect of the test object on sensitive tissues or the increase of the concentration of the test object and/or its metabolites in sensitive tissues
3.6
target organ
organ with significant toxic effect caused by the test object.
3.7
aerodynamic equivalent diameter; AD
a special term used to describe the size of aerosol particles
Comparing aerosol particles of different shapes and densities with spherical particles of different diameters with standard unit density (1.0g/cm3), when both kinds of particles have the same terminal settling velocity, the diameter of the aerosol particles is expressed by the diameter of the standard spherical particles, and is called the aerodynamic equivalent diameter of the aerosol particles, expressed in micrometers (μm).
3.8
mass median aerodynamic diameter; MMAD
when the particles smaller than or equal to a certain aerodynamic equivalent diameter (for example, 5μm) account for 50% of the total mass or total weight of an aerosol sample composed of particles of different aerodynamic equivalent diameters, the aerodynamic equivalent diameter of this kind of aerosol particles is the mass median aerodynamic diameter (5μm) of the aerosol sample
3.9
geometric standard deviation; GSD
the geometric standard deviation of the aerodynamic equivalent diameter of aerosol particles, which is used to describe the uniformity or dispersion of aerosol particle size. The smaller the geometric standard deviation is, the higher the content of particles of similar size will be, that is, the better the uniformity of aerosol particles is, the lower the dispersion will be. In general, aerosol sample with geometric standard deviation less than or equal to 2 is called monodisperse aerosol
3.10
inhalable diameter
aerosol particles with aerodynamic equivalent diameter less than 10μm are usually called inhalable particulate matters, of which the aerodynamic equivalent diameter is referred to as inhalable diameter for short
4 Test purpose
Through short-term repeated dose 28-day inhalation toxicity study, the inhalation toxicity characteristics and dose-response relationship of the test object are further understood, and information such as toxicity characteristics, target organs, whether the test object has cumulative toxicity, no observed adverse effect level (NOAEL) and lowest observed adverse effect level (LOAEL) are obtained, so as to provide basis for selection of dose and observation indexes of subchronic and chronic toxicity studies.
5 Test overview
The test object is prepared into gaseous, vapor, aerosol or granular suspension with a specific concentration. The tested animal is then repeatedly exposed to it for 28d in a short term by a dynamic exposure system and is then observed for toxic reaction, regularly weighed, has the food intake calculated, and is also subjected to the determination of hematological indexes, blood biochemical indexes and histopathological examination indexes, so as to evaluate the short-term repeated inhalation toxicity of the test object and preliminarily determine the dose and target organ(s) of the test object causing adverse effects in animals.
6 Test methods
6.1 Preparation for test
6.1.1 Test object
The test object shall be sample with stable preparation process and conforming to the quality standards, with the name, source, batch number, content (or specification), storage conditions, preparation method, etc. indicated, and the inspection report accompanied. Excipients, solvents or other media adopted shall be provided with batch number, specifications and manufacturer.
6.1.2 Selection of method and preparation for gasification or aerosol preparation of the test object
6.1.2.1 Gaseous test object
The test object is mixed with air into a certain concentration through the flowmeter, and then the gas mixture is directly introduced into the exposure cabinet.
6.1.2.2 The volatile liquid test object with lower boiling point
After being volatilized by air bubbling or appropriate heating, the test object is mixed with air into the exposure cabinet.
6.1.2.3 Non-volatile liquid test object with high boiling point
According to the physical and chemical properties of the test object, the spray method may be selected, or an aerosol generator may be used to prepare liquid aerosol meeting the test requirements, and then the liquid aerosol is mixed with a certain amount of air into the exposure cabinet.
6.1.2.4 Powdery or solid test object
The test object is prepared into solid aerosol by an aerosol generator, and is then mixed with a certain amount of air into the exposure cabinet.
6.1.3 Exposure method
To perform the short-term repeated dose inhalation toxicity study, dynamic exposure method shall be adopted by continuously and uniformly sending the air containing the test object with a certain concentration into the exposure cabinet with mechanical ventilation device at a ventilation rate of about 12~15 times/h, so as to maintain a relatively stable exposure concentration. The animal is then subjected to inhalation exposure for 6h continuously every day by systemic exposure or nose/head-only exposure. During exposure, the gas for exposure in exposure cabinet shall be distributed evenly, with the oxygen content of not less than 19% and CO2 content of not more than 3%, and shall be maintained at a temperature of (22±3)℃ and a relative humidity of 30%~70% (except for special circumstances, such as vapor exposure). In case of the systemic exposure of the animal, the total volume of laboratory animals shall not exceed 5% of the volume of the exposure cabinet in order to ensure that the air inside the exposure cabinet is stable. Weak negative pressure shall be maintained in the exposure cabinet to prevent the test object from leaking and polluting the surrounding environment. At the same time, attention shall be paid to preventing the test object from exploding.
Foreword I
1 Scope
2 Normative references
3 Terms and definitions
4 Test purpose
5 Test overview
6 Test methods
7 Test results and evaluation
8 Test report
