Fish and Housing:** Japanese eel (*Anguilla japonica*) with an average body weight of 160 g were obtained and kept in tanks with running filtered water at an average temperature of 27°C. [1]
* **Intravascular Administration:** Fish were anesthetized in ice-water for 5-10 minutes. Sulfamonomethoxine was dissolved in diluted NaOH, neutralized with HCl, and prepared in sterile saline at 100 mg/mL. This solution was injected into the caudal vein at a single dose of 200 mg/kg body weight. [1]
* **Oral Administration:** Fish were anesthetized in ice-water for 5-10 minutes. Sulfamonomethoxine was mixed with a fish diet and administered orally via a catheter at a single dose of 400 mg/kg body weight. [1]
* **Sampling:** Five fish were sampled at intervals ranging from 0.5 hours to 40 days after administration. Blood was collected from the caudal vein using a syringe. Serum was obtained by centrifugation after overnight refrigeration and stored at -40°C until analysis. [1]
* **Analytical Procedure for Serum Samples:** Serum (1-4 mL) was homogenized in acetone. After centrifugation, n-propanol was added to the supernatant, and the mixture was concentrated. The concentrated solution was transferred to a separatory funnel with acetone, n-hexane, and 3% NaCl. After shaking and discarding the organic layer, the n-hexane wash was repeated. Chloroform was then added and the mixture was shaken. The chloroform layer containing the drug was collected, pooled, and concentrated. This concentrated solution was applied to a purification cartridge that had been pre-washed with acetonitrile. The drug and its metabolite were eluted with 70% acetonitrile. The eluate was evaporated to dryness, and the residue was dissolved in 30% acetonitrile for HPLC injection. The average recovery was 80%, and the detection limit was 0.05 μg/mL. [1]
* **HPLC Conditions:** The HPLC system used a UV detector set at 265 nm. The analytical column was a C18 reversed-phase column. The mobile phase was 0.05 M phosphate buffer (pH 2.5) and acetonitrile (65:35) at a flow rate of 0.5 mL/min. The injection volume was 20 μL, and the system was operated at room temperature. [1]
* **Pharmacokinetic Analysis:** Pharmacokinetic analysis was performed assuming a one- or two-compartment model using the non-linear least-squares program MULTI. Model selection was based on Akaike's information criterion. The area under the concentration-time curve (AUC) was calculated using the trapezoidal rule. Mean residence time (MRT) was obtained by non-compartmental analysis based on statistical moment theory. [1]

[1]. Ryuji Ueno. Pharmacokinetics and Bioavailability of Sulfamonomethoxine in Cultured Eel. Fish Pathology,33(4),297-301,1998.10.

[2]. Environ Sci Pollut Res Int. 2014 Jun;21(12):7436-48.

Sulfamonomethoxine is a sulfonamide compound, belonging to the benzene family. It is a long-acting sulfonamide antibiotic. It is a long-acting sulfonamide antibacterial agent.

C11H12N4O3S

280.3030

280.063

C, 47.14; H, 4.32; N, 19.99; O, 17.12; S, 11.44

1220-83-3

Sulfamonomethoxine-d4;1286538-12-2;Sulfamonomethoxine sodium;38006-08-5;Sulfamonomethoxine-d3;Sulfamonomethoxine-13C6;1416768-32-5;Sulfamonomethoxine-d3-1;2704162-84-3

5332

Solid powder

1.3936

513℃

203-206°C

>110°

0.0±1.3 mmHg at 25°C

1.6200

-0.04

2

7

4

19

376

0

S(C1C([H])=C([H])C(=C([H])C=1[H])N([H])[H])(N([H])C1=C([H])C(=NC([H])=N1)OC([H])([H])[H])(=O)=O

WMPXPUYPYQKQCX-UHFFFAOYSA-N

InChI=1S/C11H12N4O3S/c1-18-11-6-10(13-7-14-11)15-19(16,17)9-4-2-8(12)3-5-9/h2-7H,12H2,1H3,(H,13,14,15)

4-Amino-N-(6-methoxypyrimidin-4-yl)benzenesulfonamide

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 : 56~100 mg/mL ( 199.78~356.76 mM)
H2O : ~1 mg/mL (~3.57 mM)
Ethanol : ~4 mg/mL

Solubility in Formulation 1: ≥ 2.5 mg/mL (8.92 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 (8.92 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: 10% DMSO+40% PEG300+5% Tween-80+45% Saline: ≥ 2.5 mg/mL (8.92 mM)

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