The main mode of action of phenylurea-cytokinins like thidiazuron is to inhibit cytokinin oxidases, allowing endogenous cytokinins to have a longer half-life. TDZ stimulates cell division and differentiation, leading to enhanced shoot formation and lateral branching in plants. It promotes growth and various developmental processes in plants. TDZ has been shown to be highly active in promoting the growth of cytokinin-dependent callus. Its biological effects are highly concentration-dependent and species-specific, often inducing somatic embryogenesis where purine-based cytokinins like BAP fail. The compound interacts with cytokinin signaling pathways in plants.

For micropropagation, thiadiazuron is a plant growth regulator added to media like Skoog and Murashige. Thidiazuron encourages both plant regeneration and organogenesis, or shoot regeneration.

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In vitro, thidiazuron has been used as a component of proliferation medium to test its effect on the proliferation of embryo-like structures obtained from shoot tips. It promotes soybean callus growth and radish cotyledon expansion. TDZ is used in plant tissue culture to supplement media such as Murashige and Skoog medium. It stimulates cell division and differentiation in cultured plant tissues. The compound's cytokinin activity is highly potent at low concentrations. Cellular assays typically evaluate its effects on plant cell proliferation, shoot regeneration, and somatic embryogenesis.

In vivo, thidiazuron is applied to plants as a growth regulator to promote shoot formation and lateral branching. It is used in micropropagation techniques for plant breeding and biotechnology. TDZ stimulates somatic embryogenesis and plant regeneration in various species. Its biological effects are species-specific and concentration-dependent. The compound has been found to have significant cytokinin activity in promoting growth and developmental processes in whole plants. TDZ is effective as a foliar spray or media supplement in horticultural and agricultural applications.

In vitro enzyme/receptor binding assays for thidiazuron typically evaluate its activity as a cytokinin. The compound interacts with cytokinin receptors and inhibits cytokinin oxidase enzymes. A typical assay protocol involves incubating TDZ with plant tissues or cell cultures in appropriate growth medium. Cytokinin activity is assessed by measuring cell proliferation, shoot regeneration, or callus growth. The compound's ability to inhibit cytokinin oxidases can be measured using enzyme activity assays with purified enzymes or tissue extracts. Binding to cytokinin receptors can be evaluated using competitive binding assays with radiolabeled cytokinins.

Cellular assays for thidiazuron typically involve evaluating its effects on plant cell proliferation and differentiation. A standard protocol includes culturing plant cells, callus, or tissues in Murashige and Skoog medium supplemented with TDZ at concentrations ranging from 0.01-10 μM. Cultures are maintained at appropriate temperature (typically 25°C) with a 16-hour light/8-hour dark photoperiod. Cell proliferation is assessed by measuring fresh weight, dry weight, or cell number. Shoot regeneration and somatic embryogenesis are evaluated by counting the number of shoots or embryos formed. The compound's cytokinin activity is compared to standard cytokinins like BAP or kinetin.

In vivo animal studies are not applicable for thidiazuron, as it is a plant growth regulator used exclusively in plant systems. The compound is not intended for animal or human use. All applications of TDZ are in the context of plant tissue culture, micropropagation, and agricultural research. The compound is classified for research use only and is not intended for veterinary or human therapeutic applications. Any studies involving animals would be limited to toxicological evaluations of the compound as an environmental or agricultural chemical, though such data is not readily available in the public literature.

Absorption, Distribution and Excretion
[(14)C-aniline]thiazidron was administered at a 1.9-fold dose (10 ppm) to a lactating cow for 7 consecutive days. The animal was sacrificed within 24 hours of the last administration. Maternal radioactivity was detected at 0.05 ppm, 0.1 ppm, 1.5 ppm, and 1.0 ppm in fat, muscle, kidney, and liver, respectively. Radioactivity in milk plateaued at 0.2 ppm on the second day. Analysis was performed using high-performance liquid chromatography (HPLC) and thin-layer chromatography (TLC). [(14)C-aniline]thiazidron was administered at a 100-fold dose (8 ppm) to six hens once daily for 14 consecutive days. During this period, radioactivity in eggs did not plateau. All tissues were treated with protease and β-glucuronidase prior to extraction. The maternal equivalent radioactivity was detected in fat, gastrointestinal tract, gastrointestinal contents, liver, muscle, skin, and blood at levels of 0.02 ppm, 0.27 ppm, 1.11 ppm, 0.66 ppm, 0.10 ppm, 0.10 ppm, and 0.34 ppm, respectively. In a metabolic study, male and female Sprague-Dawley CD rats were administered (14)C-thiazuron [((14)C-aniline)thiazuron or ((14)C-thiadiazoline)thiazuron (purity: >97% ai; batch numbers: 1695-3 and 1695-4)] via single gavage or oral administration of thiazuron 10 mg/kg for 14 consecutive days, followed by a single oral administration. (14)C-thiazidron, at a dose of 10 mg/kg… Preliminary results indicate that, regardless of whether it is ((14)C-aniline)thiazidron or ((14)C-thiadiazolin)thiazidron, less than 0.2% of the administered dose is excreted as (14)CO2 after administration. Furthermore, the study showed no significant difference in the percentage of thiazidron excreted in urine or feces between the two radiolabeled forms. Thiazidron is rapidly but incompletely absorbed at both doses, with absorption appearing to be lower in the high-dose group than in the low-dose group. Elimination is relatively rapid with a single low-dose oral dose of thiazidron. The primary elimination route is urine. Studies of single low-dose, single high-dose, and multiple low-dose oral administrations showed that the total radioactive material recovered from urine and feces within 5 days after administration accounted for 91%–104% of the administered dose. In the low-dose group, the radioactivity recovered from urine and feces within 5 days was 60–66% and 29–31% of the administered dose, respectively. In the repeated oral administration group, the radioactivity recovered in urine and feces over 5 days was 73-75% and 26-28% of the administered dose, respectively. In the high-dose group, the radioactivity recovered in urine and feces over 5 days was 41-47% and 56-60% of the administered dose, respectively. A single high-dose administration resulted in a decrease in the percentage of thiamethoxam-derived radioactive material excreted in urine (approximately 20%), while fecal excretion increased. This change is likely due to reduced absorption of the test substance at high doses. Terminal tissue distribution data showed that, regardless of the low-dose or high-dose group, the highest concentrations of thiamethoxam-derived radioactive material were found in the liver, kidneys, thyroid gland, whole blood, and adrenal glands at the time of sacrifice. Repeated oral administration did not significantly affect the distribution of thiamethoxam-derived radioactive material. In a skin penetration study, thiabendazole (99.9% ai, batch number OR 1844 (SEL/1098), [phenyl-U-(14)C]-thiabendazole) was applied to a 12 cm² area on the back of five male Sprague Dawley CD rats at dose levels of 5.0, 0.04, and 0.004 mg/cm², in the form of the formulation and its aqueous dilution. The mean total recovery rate for all groups ranged from 88% to 99.54% of the dose. Twenty-four hours after exposure, the radioactive material content in the stratum corneum of the high, medium, and low dose groups was 0.73%, 10.68%, and 8.14%, respectively; eight hours after exposure, the radioactive material content in the stratum corneum of the high, medium, and low dose groups was 0.41%, 3.24%, and 5.37%, respectively. However, the results indicate that most of the radioactive material in the stratum corneum is lost with the shedding and regeneration of the stratum corneum.
Thiaziron (N-phenyl-N'-1,2,3-thiadiazole-5-ylurea) cotton defoliant was administered to lactating goats and laying hens for 10 consecutive days. The vast majority of the radioactive material (>70%) was excreted through the goats' urine and feces; the radioactive material content in milk was less than 1.5%. During the 10-day feeding period, hens excreted 72% of the total ingested radioactive material. In addition to the maternal compound, which was found in low levels in goat milk, chicken feces, eggs, liver, and kidneys, N-4-hydroxyphenyl-N'-1,2,3-thiol-5-ylurea or 4-hydroxyphenylthiaziron and phenylurea were also detected. 4-Hydroxyphenylthiaziron is the major metabolite of thiaziron and exists in free and/or bound forms in the feces, milk, eggs, and certain tissues of goats and hens. Phenyurea was detected only in goat urine. Other unidentified compounds were also present.

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Metabolism/Metabolites
Thidiazuron (N-phenyl-N'-1,2,3-thiadiazole-5-ylurea) cotton defoliant was administered to lactating goats and laying hens for 10 consecutive days. The vast majority of the radioactive material (>70%) was excreted through the urine and feces of the goats; the radioactive material content in the milk was less than 1.5%. During the 10-day feeding period, laying hens excreted 72% of the total ingested radioactive material. In addition to the parent compound, which was found in low concentrations in goat milk and chicken feces, eggs, liver, and kidneys, N-4-hydroxyphenyl-N'-1,2,3-thiol-5-ylurea or 4-hydroxyphenylthidiazuron and phenylurea were also detected. 4-Hydroxyphenylthidiazuron is the major metabolite of thidiazuron and exists in free and/or bound forms in the feces, milk, eggs, and certain tissues of goats and chickens. Phenyurea was detected only in goat urine. Furthermore, other unidentified compounds were present. In a rat oral metabolism study… the identification of urinary metabolites revealed the presence of oxidative metabolites (4-hydroxythiazidime) and 4-hydroxythiazidime sulfate and glucuronide conjugates in the urine. In feces, the major metabolite was 4-hydroxythiazidime in the low-dose group and unmetabolized thiazidime in the high-dose group.

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Pharmacokinetic data for thidiazuron is not applicable in the context of animal or human pharmacology, as it is a plant growth regulator. The compound has a molecular weight of 220.25 g/mol and is a white to off-white powder. It is soluble in DMSO and 0.1 N KOH. The compound is stored at room temperature or 2-8°C. In plant systems, TDZ is taken up through roots or foliar application and is translocated to target tissues. Its persistence and metabolism in plants depend on species and environmental conditions.

Toxicity Summary
The U.S. Environmental Protection Agency (EPA) has not found any information indicating that thiamethoxam shares a common toxic mechanism with other substances. (L2080) Toxicity Data
LC50 (Rats) > 3,480 mg/m³ LD50 > 2 g/kg (L2080). Non-Human Toxicity Values LD50 (Rats, dermal contact) > 4000 mg/kg LD50 (Rats, oral) > 2000 mg/kg LD50 (Rats, dermal contact) > 5000 mg/kg LD50 (Rats, oral) > 5350 mg/kg For more non-human toxicity values (complete data) for thiamethoxam (out of 8), please visit the HSDB record page.

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Toxicological data for thidiazuron in animals and humans is limited, as it is a plant growth regulator not intended for human use. The compound is classified for research use only. Standard safety precautions include handling with appropriate personal protective equipment (gloves, lab coat, safety goggles) in a well-ventilated area. The compound should be stored at room temperature or 2-8°C. Acute toxicity data is not readily available in the public literature. As with all research chemicals, appropriate laboratory safety practices should be followed. No specific LD₅₀ values or detailed toxicological profiles are available in the public domain.

Thidiazuron belongs to the urea family of compounds. It has been reported that white water lilies contain Thidiazuron, and relevant data is available for reference. Thidiazuron is a herbicide, defoliant, and plant growth regulator, primarily used in cotton crops. It can be absorbed by the leaves.

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Thidiazuron (TDZ, CAS 51707-55-2) is a synthetic diphenylurea cytokinin and plant growth regulator. It has a molecular formula of C₉H₈N₄OS and a molecular weight of 220.25 g/mol. The compound is also known as 1-Phenyl-3-(1,2,3-thiadiazol-5-yl)urea. TDZ is used in plant tissue culture, micropropagation, and somatic embryogenesis. It is classified as a research-use-only compound not intended for diagnostic or therapeutic purposes. The compound is available from multiple commercial suppliers in various pack sizes. No clinical trials or approved drug status exist for this compound as it is not a therapeutic agent.

C9H8N4OS

220.25

220.041

51707-55-2

40087

Colorless crystals

1.5±0.1 g/cm3

410.5±55.0 °C at 760 mmHg

210.5 - 212.5 °C (decomposes)

202.1±31.5 °C

0.0±1.0 mmHg at 25°C

1.722

1.81

2

4

2

15

220

0

O=C(NC1=CN=NS1)NC2=CC=CC=C2

HFCYZXMHUIHAQI-UHFFFAOYSA-N

InChI=1S/C9H8N4OS/c14-9(12-8-6-10-13-15-8)11-7-4-2-1-3-5-7/h1-6H,(H2,11,12,14)

1-phenyl-3-(thiadiazol-5-yl)urea

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

DMSO: 100 mg/mL (454.03 mM)

Solubility in Formulation 1: ≥ 2.5 mg/mL (11.35 mM) (saturation unknown) in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 400 μL PEG300 and mix evenly; then add 50 μL Tween-80 to the above solution and mix evenly; then add 450 μL normal saline to adjust the volume to 1 mL.
Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution.

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Solubility in Formulation 2: ≥ 2.5 mg/mL (11.35 mM) (saturation unknown) in 10% DMSO + 90% (20% SBE-β-CD in Saline) (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 900 μL of 20% SBE-β-CD physiological saline solution and mix evenly.
Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution.

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Solubility in Formulation 3: ≥ 2.5 mg/mL (11.35 mM) (saturation unknown) in 10% DMSO + 90% Corn Oil (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 900 μL of corn oil and mix evenly.

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 (Please use freshly prepared in vivo formulations for optimal results.)