Classification of pesticides, pesticides commonly used in our country which types of dosage forms, what are their characteristics

A pesticide can be processed into many kinds of dosage forms, common dosage forms are powder, granule, wettable powder, soluble powder, thick suspension and colloidal agent, emulsifiable oil, seed coating agent, oil, slow-release agent, smoke agent.

(1) Powder (D). Powder is a very fine powdery mixture, 95% of the powder particles can pass through a 200 mesh sieve (sieve hole inner diameter of 74um). Mainly for spray powder use of low concentration powder can be directly sprayed, suitable for water sources difficult areas to use; high concentration powder for seed mixing, preparation of poisonous soil and other uses. Powder can not be used for water spray.

3.2 Granules (G). Granular dosage form processed from the original drug, carrier and additives. It is derived from the powder and the development of multi-specification, multi-form, multi-purpose dosage form. Granules are categorized into microparticulate, granular and large granular dosage forms according to the size of the particle, and those with a particle size larger than that of large granules are known as block dosage forms, or pill dosage forms. According to the differentiation of carrier disintegration, the granules that are not dispersed in water are called non-disintegrating granules, and the granules that are dispersed in water are called disintegrating granules. The active ingredients of non-disintegrating granules are gradually released from the carrier to exert the medicinal effect, and mostly appear as granules or particles, with a wide variety of preparations and uses. Disintegrating granules are also known as water-dispersible granules, and are mostly found as granules or pellets. Mostly used for soil treatment.

(3) Wettable powder (WP). Easily wetted by water and can be dispersed in water, suspended powder dosage form. To insoluble in water of the original drug and wetting agent, dispersant, filler mixed, crushed and become. The agent can be diluted with water into a stable, well-dispersed suspension for spraying. Wettable powder in pesticide dosage form occupies a more important position, compared with emulsifiable oil, it does not use organic solvents and emulsifiers; it has some advantages of powder, such as packaging, transportation costs are low, and the active ingredient content of the general powder is high, and more resistant to storage. Especially herbicides, fungicides are mostly solid drug, some of which are difficult to dissolve in water, and difficult to dissolve in organic solvents, which is not suitable for processing into emulsifiable oil, but suitable for processing into wettable powder. The efficacy of wettable powder is better than the powder of the same original drug. It can also be used for seed mixing, soil treatment, root irrigation, preparation of poisonous soil, poisonous bait and so on.

(4) soluble powder (WS). Preparation appearance like wettable powder, and the active ingredient content is usually higher than wettable powder. The same agent, the two active ingredient content is the same, soluble powder efficacy is higher than wettable powder, packaging, transportation is also convenient; compared with emulsifiable concentrate, similar efficacy, but do not need to use organic solvents, additives, the amount of relatively small, which not only reduces the product cost, but also on the environment is relatively safe. The dosage form can be used after dilution with water, and special attention should be paid to moisture-proof packaging and dry storage.

(5) concentrated suspension. Solid drug dispersion, suspended in the water medium containing a variety of additives or oil medium can flow in a high concentration of viscous agent type. Water as the medium of concentrated suspension is often referred to as suspension; and oil as the medium of concentrated suspension is often referred to as oil suspension, can be used for aircraft or ultra-low volume spray. It has some advantages of both emulsifiable oil and wettable powder, and is resistant to rain, non-flammable, and not easy to appear drug damage, etc.; it can be mixed with water in any proportion.

(6) emulsifiable concentrate (EC). Into the water can be dispersed into an emulsion of oil homogeneous liquid dosage form. Emulsified oil processing equipment used in simple, easy to master the preparation technology, that is, the original drug dissolved in organic solvents, plus emulsifiers, the three mutually soluble and become. Emulsified oil in the active ingredient content is high, generally good storage stability, high efficacy, easy to use. Emulsifiable concentrate can not be directly sprayed, the requirements of water diluted into a certain concentration of emulsion, sprayed with a sprayer. Emulsifiable concentrate has many advantages, but the biggest disadvantage is the consumption of a large number of organic solvents, pollution of the environment, flammable and unsafe. Therefore, other dosage forms containing no or less organic solvents have been emphasized, such as concentrated emulsions, suspensions, and aqueous agents.

(7) concentrated emulsion. For water-in-oil opaque emulsion pesticide dosage form. Water insoluble pesticide crude oil, emulsifier, dispersant, stabilizer, antifreeze and water as raw materials by homogenization process and made without or with less organic solvents. The dosage form of emulsion characteristics or advantages of water as a continuous phase, pesticide crude oil for the dispersed phase, water can inhibit pesticide vapor volatilization, the production cost is lower than emulsions, no combustion, explosion hazards, storage and transportation safety, to avoid the hazards of organic solvents on the environment, animals and crops. Concentrated emulsion can be used directly for aircraft or ground spraying. It can also be used to do constant spraying on water.

(8) Aqueous agent. Pesticide original drug of the water solution dosage form. Aqueous agent contains a small amount of surfactant. This is a molecular or ionic state of the agent dispersed in water in a true solution formulation, the concentration depends on the solubility of the active ingredient of pesticides, and requires good stability of the original drug in the water, the use of the basic and the thick emulsion is basically the same as the above. Dedicated to the treatment of seeds is called seed treatment of water. Used to control indoor health pests, often processed into aromatic water. All water-soluble and water-stable drug can be processed into water.

(9) seed coating agent.

Containing adhesive pesticides coated in the plant seeds outside and form a relatively strong layer of agent. Seeds treated with it can often be stored for a period of time, so some seed companies will sell this as commercial seeds. If you use conventional formulations such as powder, emulsion, etc., seed mixing or soaking, it is called seed treatment, usually with the treatment with the seed.

(10) oil. Pesticide original oil solution dosage form. The agent is designed for ultra-low-volume spraying, also known as ultra-low-volume spray. The dosage form generally contains 20% to 50% of the active ingredient of the pesticide, without dilution and direct spraying.

(11) slow release agent. Can control the pesticide active ingredient from the processed products in the slow release of pesticide formulations. The use of physical and chemical means to make pesticides stored in pesticides in the processed products, and then make it a controlled release. At present, some foreign slow-release agent has been commercialized, the country is accelerating research, mainly to explore the slow-release agent processing technology, and study the relationship between the release rate and environmental conditions.

(12) smoke agent. Fine powdered mixture, ignited, the active ingredient in smoke-like dispersion system suspended in the air pesticide dosage form. Used by ignition, it can burn, but should only emit smoke without flame. Pesticide active ingredients due to heat and vaporization, cooling in the air and coalescence into very small solid particles, deposited on the plant surface. Tiny smoke particles not only have a good touch and stomach poisonous effect on pests, but also through the respiratory tract of pests into the body and play a toxic role. The use of smoke also has the advantages of high efficiency and low labor intensity. To be used in the environment under closed conditions, such as protected areas.