Absorption, Distribution and Excretion
This study investigated the skin absorption of RH-287 in male CR1:CD:BR rats. The experiment consisted of six groups, with four rats in each group. RH-287 was administered at two concentrations: 3% and 0.045%. 60 μL of RH-287 solution was applied to the interscapular region of the back, after which the rats were shaved. A fitted glass ring was then fixed in place with cyanoacrylate glue, and the top of the ring was secured with a rubber band. Groups A and B received 3% and 0.045% RH-287 solutions, respectively. Urine and fecal samples were collected 10 hours after administration. The animals were then sacrificed, and whole blood, plasma, and remaining carcasses were analyzed for radioactivity. The other two groups (Groups C and D) received either 3% or 0.045% RH-287, and underwent the same experimental procedures as Groups A and B, but with a 24-hour exposure period. The last two groups (Group E and Group F) also received 3% or 0.045% RH-287, respectively, and urine and fecal samples were collected at 0, 10, 24, 48, and 72 hours after administration. Animals in these groups were sacrificed 72 hours after administration and subjected to radioactive analysis using the same methods as the other groups. The results showed that the absorption rate of 0.045% RH-287 was 44-50% after 10 hours of exposure and 70% after 24 hours. The absorption rate of 3% RH-287 was 31-34% after 10 hours of exposure and 52% after 24 hours.

Toxicity Summary
Identification and Uses: 4,5-Dichloro-2-octyl-3-isothiazolinone (DCOIT) is a solid used as a marine antifouling agent. Human Studies: An outbreak of occupational contact dermatitis was caused by the bactericide DCOIT. Eight out of nineteen employees (six women, aged 20 to 63 years) at a textile finishing plant in Japan developed edematous, red rashes on their forearms, upper arms, face, or neck. All subjects were hypersensitive to DCOIT, but no significant cross-sensitization was observed. Animal Studies: Treatment with DCOIT at a concentration of 1500 ppm resulted in decreased body weight and food consumption in dogs, as well as changes in hematological and clinical chemistry parameters. In rats, after inhalation of the drug at concentrations of 0.02, 0.63, and 6.72 mg/m³ for 6 hours daily, 5 days a week for 13 weeks, treatment-related microscopic lesions were observed in the nose, larynx, and lungs of rats in both the medium- and high-dose groups. An increased incidence of mild or mild subacute inflammation was observed in the nose, along with transitional respiratory epithelial hyperplasia and goblet cell hyperplasia. In the epiglottis, squamous and cuboidal epithelial hyperplasia, as well as chronic active inflammation, were observed in both the medium- and high-dose groups. An increased incidence of goblet cell hyperplasia and acute inflammation was observed in the lungs of rats in the high-dose group. In rabbit developmental studies, no treatment-related external, visceral, or skeletal malformations or variations were observed. In rats, administration at a dose of 100 mg/kg/day increased the number of fetuses with wavy rib deformities, along with an increase in the number of parities and the severity of the deformity. The drug was non-mutagenic against Salmonella strains TA1535, TA1537, TA98, and TA100, regardless of metabolic activation. In in vitro cytogenetics assays, the drug induced chromosome breakage in the ovaries of Chinese hamsters, regardless of metabolic activation. Ecotoxicity studies: In marine medaka (Oryzias melastigma), gene transcription analysis showed that DCOIT primarily had a positive regulatory effect on the male hypothalamic-pituitary-gonadal-hepatic axis, with a smaller effect on females. Stimulated steroidal activity led to increased plasma concentrations of steroid hormones (including estradiol (E2), testosterone (T), and 11-ketotestosterone (11-KT)) in both males and females, resulting in hormonal homeostasis imbalance and an increased E2/T ratio. Relatively high estrogen levels in both males and females induced the synthesis of vitellogenin (VTG) or pro-human chorionic gonadotropin in the liver and increased the levels of these two hormones in the liver and plasma. Furthermore, parental exposure to DCOIT impaired offspring survival across generations, as evidenced by decreased hatching rates and swimming abilities. After 28 days of exposure at an environmentally realistic concentration of 2.55 μg/L, DCOIT induced differential expression of 26 proteins in the brain tissue of male marine medaka (Oryzias melastigma) and 27 proteins in the brain tissue of females. Interactions In two microalgae studies, the individual and mixed toxicities of three antifouling agents (Sea-Nine, Irgarol, and TBT) were determined. Their effects on photosynthesis in attached biomes and the reproduction of the single-celled green algae Scenedesmus vacuolatus were investigated. In both studies, the tested antifouling agents exhibited high toxicity. The observed mixed toxicities were compared with predicted values based on two concepts: Independent Action (IA), considered more applicable to mixtures composed of substances with different effects; and Concentration Addition (CA), considered a reasonable worst-case method for predicting the hazard assessment of mixtures. Despite the underlying mechanisms, the IA method failed to accurately predict observed mixture toxicity. Results from both detection methods exhibited the same pattern: mixture effects at high concentrations were slightly overestimated, while those at low concentrations were slightly underestimated. The maximum deviation between observed and IA-predicted concentrations was up to four times. The proposed worst-case approach using CA is only protective in the region where the effect value is above 20%. However, any concept that considers possible mixture effects is more realistic than the current approach of assessing chemicals individually.

[1].Isothiazolinone Disrupts Reproductive Endocrinology by Targeting the G-Protein-Coupled Receptor Signaling. Environ Sci Technol. 2024 Jan 3.

4,5-Dichloro-2-n-octyl-3(2H)-isothiazolinone is a 1,2-thiazolium compound with the structure 1,2-thiazol-3(2H)-one, where chlorine atoms are substituted at positions 4 and 5, and an octyl atom is substituted at position 2. It can be used as a bactericide. It is both an environmental pollutant and an exogenous substance. It is an organochlorine compound belonging to the 1,2-thiazolium class of compounds.

C11H17CL2NOS

282.23

281.04

64359-81-5

91688

Crystals from hexane

1.3±0.1 g/cm3

322.6±52.0 °C at 760 mmHg

36-40ºC

148.9±30.7 °C

0.0±0.7 mmHg at 25°C

1.552

4.34

0

2

7

16

281

0

ClC1=C(SN(C1=O)C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])C([H])([H])[H])Cl

PORQOHRXAJJKGK-UHFFFAOYSA-N

InChI=1S/C11H17Cl2NOS/c1-2-3-4-5-6-7-8-14-11(15)9(12)10(13)16-14/h2-8H2,1H3

4,5-dichloro-2-octyl-1,2-thiazol-3-one

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)

Typically soluble in DMSO (e.g. 10 mM)

Note: Listed below are some common formulations that may be used to formulate products with low water solubility (e.g. < 1 mg/mL), you may test these formulations using a minute amount of products to avoid loss of samples.

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Injection Formulation 1: DMSO : Tween 80： Saline = 10 : 5 : 85 (i.e. 100 μL DMSO stock solution → 50 μL Tween 80 → 850 μL Saline)
*Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH ₂ O to obtain a clear solution.
Injection Formulation 2: DMSO : PEG300 ：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL DMSO → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline)
Injection Formulation 3: DMSO : Corn oil = 10 : 90 (i.e. 100 μL DMSO → 900 μL Corn oil)
Example: Take the Injection Formulation 3 (DMSO : Corn oil = 10 : 90) as an example, if 1 mL of 2.5 mg/mL working solution is to be prepared, you can take 100 μL 25 mg/mL DMSO stock solution and add to 900 μL corn oil, mix well to obtain a clear or suspension solution (2.5 mg/mL, ready for use in animals).

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Injection Formulation 4: DMSO : 20% SBE-β-CD in saline = 10 : 90 [i.e. 100 μL DMSO → 900 μL (20% SBE-β-CD in saline)]
*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.
Injection Formulation 5: 2-Hydroxypropyl-β-cyclodextrin : Saline = 50 : 50 (i.e. 500 μL 2-Hydroxypropyl-β-cyclodextrin → 500 μL Saline)
Injection Formulation 6: DMSO : PEG300 : castor oil : Saline = 5 : 10 : 20 : 65 (i.e. 50 μL DMSO → 100 μLPEG300 → 200 μL castor oil → 650 μL Saline)
Injection Formulation 7: Ethanol : Cremophor : Saline = 10： 10 : 80 (i.e. 100 μL Ethanol → 100 μL Cremophor → 800 μL Saline)
Injection Formulation 8: Dissolve in Cremophor/Ethanol (50 : 50), then diluted by Saline
Injection Formulation 9: EtOH : Corn oil = 10 : 90 (i.e. 100 μL EtOH → 900 μL Corn oil)
Injection Formulation 10: EtOH : PEG300：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL EtOH → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline)

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Oral Formulation 1: Suspend in 0.5% CMC Na (carboxymethylcellulose sodium)
Oral Formulation 2: Suspend in 0.5% Carboxymethyl cellulose
Example: Take the Oral Formulation 1 (Suspend in 0.5% CMC Na) as an example, if 100 mL of 2.5 mg/mL working solution is to be prepared, you can first prepare 0.5% CMC Na solution by measuring 0.5 g CMC Na and dissolve it in 100 mL ddH2O to obtain a clear solution; then add 250 mg of the product to 100 mL 0.5% CMC Na solution, to make the suspension solution (2.5 mg/mL, ready for use in animals).

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Oral Formulation 3: Dissolved in PEG400
Oral Formulation 4: Suspend in 0.2% Carboxymethyl cellulose
Oral Formulation 5: Dissolve in 0.25% Tween 80 and 0.5% Carboxymethyl cellulose
Oral Formulation 6: Mixing with food powders

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Note: Please be aware that the above formulations are for reference only. InvivoChem strongly recommends customers to read literature methods/protocols carefully before determining which formulation you should use for in vivo studies, as different compounds have different solubility properties and have to be formulated differently.

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