Sulfamethizole

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Cat Number

API0231615

CAS Number

144-82-1

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Product Detail Description Scientific Support Customer Q&A

CAS Number

144-82-1

EINECS

205-641-1

Storage

Store at room temperature

Synonyms

Sulfamethizol; Sulphamethizole; Thiosulfil; 4-Amino-N-(5-methyl-1,3,4-thiadiazol-2-yl)benzenesulfonamide

Molecular Formula

C9H10N4O2S2

Molecular Weight

270.3

Smiles

CC1=NN=C(S1)NS(=O)(=O)C2=CC=C(C=C2)N

Appearance

White to off-white powder to crystal

Melting Point

208-210℃

Boiling Point

504.9℃ at 760 mmHg

Relative Density

1.562

General Description

Sulfamethizole is a short-acting sulfonamide antibiotic with a rapid onset and high urinary excretion, making it suitable for urinary tract infections. It is one of the most rapidly absorbed and eliminated sulfonamides. The drug has a thiadiazole ring that contributes to its high solubility in acidic urine.

Mechanism of Action

Sulfamethizole inhibits bacterial folic acid synthesis by competitively binding to dihydropteroate synthase, preventing incorporation of para-aminobenzoic acid (PABA) into dihydrofolic acid. This bacteriostatic effect targets rapidly dividing bacteria, especially E. coli and other gram-negative uropathogens. Human cells lack this pathway, accounting for selective toxicity. Resistance is common due to plasmid-mediated altered enzymes.

Application

Sulfamethizole is indicated for the treatment of uncomplicated lower urinary tract infections (cystitis, urethritis) caused by susceptible organisms. Due to widespread resistance, it is rarely used as first-line therapy, being reserved for documented sensitivity or alternative treatment failures.

Cold plasma technology using pulsed corona discharge oxidized the antibiotic sulfamethizole in water. Flow rate and pH had no significant effect on oxidation efficiency, while lower pulse repetition frequency improved energy efficiency but prolonged treatment time. Increasing solution temperature to 50°C markedly slowed the reaction and reduced energy efficiency. The pseudo‑first order rate constant increased with pulse frequency but was pH‑independent. The authors conclude that pulsed corona discharge is an effective method for sulfamethizole abatement, with lower temperatures and optimized frequency enhancing performance.

Fig. 1 Relationship between sulfamethizole relative concentration (C/C0) and treatment time at different pulse frequencies (50 pps, 200 pps, 500 pps) and initial pH. (Sokolov A, et al., 2018)

References

Sokolov A, Louhi-Kultanen M. Behaviour of aqueous sulfamethizole solution and temperature effects in cold plasma oxidation treatment. Sci Rep. 2018;8(1):8734.

Does Sulfamethizole require protection from light during long-term storage?

Yes, it is photosensitive. Prolonged UV exposure can cause discoloration and degradation of the sulfonamide ring. Store in light-resistant containers.

What is the recommended storage temperature for Sulfamethizole?

Store at controlled room temperature (15-25°C). Avoid excessive heat above 30°C, which can accelerate hydrolysis to sulfanilamide derivatives.

Is Sulfamethizole susceptible to moisture-induced degradation?

It is slightly hygroscopic. Under high humidity, it may absorb moisture and clump, but significant hydrolysis requires elevated temperatures. Store with desiccant for long-term stability.

How is the impurity sulfanilamide monitored during stability?

This primary degradation product is specifically quantified using a validated HPLC method, ensuring it remains below pharmacopoeial limits.