Sulfacetamide Research Articles

Efficacy of Treatments in Reducing Facial Erythema in Rosacea: A Systematic Review.

Rosacea is a chronic inflammatory skin condition that affects over 5% of individuals worldwide. Its clinical presentation is characterized by an array of features, including erythema, papules and pustules, phymatous changes, telangiectasia, and ocular manifestations. Specifically, the multifaceted manifestation of erythema varies widely in intensity and distribution. Factors contributing to pathogenesis include neurovascular dysregulation, increased levels of pro-inflammatory mediators, and aberrant vasodilation. Erythema management plays an important role in reducing the psychosocial burden associated with rosacea and improving overall quality of life. Cochrane CENTRAL, Medline, and Embase databases were searched from inception to September 2023 and included 33 clinical trials reporting on a total of 7411 rosacea patients (74.1% female) and 21 different topical or systemic treatments. The mean age was 48.8 years (range, 18-83 years), and the mean time to outcome assessment was 8.1 weeks (standard deviation, 4.1 weeks). Treatment efficacy was assessed by outcome measures including percent improvement from baseline on 4- and 5-point scales, clinician erythema assessment (CEA) success (improvement ≥1 point), and CEA and patient self-assessment success (improvement ≥1 point). Pooled effect sizes for each treatment were calculated as a weighted average based on the number of patients in each study. The most effective topical treatments for reducing erythema include sodium sulphacetamide and sulphur, praziquantel, metronidazole, and B244 spray (Nitrosomonas eutropha). The most effective systemic treatment was paroxetine. Our findings highlight the varying efficacy of treatments in addressing the erythema in rosacea, recognizing the nuances of clinical presentations.

Atomistic Analysis of Sulphonamides as a Microbial Influenced Corrosion (MIC) Inhibitor.

Four sulfonamide-type microbial inhibitors were studied using density functional theory (DFT) to assess their effectiveness in controlling microbial corrosion. The experimental techniques (FTIR, SEM, EIS, EFM, and AFM) are beneficial for measuring properties such as chemical composition, bond formation, electrochemical behavior, and surface topography; however, DFT can be useful as a new method for understanding microbial corrosion. Sulfacetamide (SFC), sulfamerazine (SFM), sulfapyridine (SFP), and sulfathiazole (SFT) uniformly adsorb onto the iron surface and block the active site, reducing the corrosion rate. To study the effect on microbial activity, a 0.6 eV electric field was applied. The absolute increase in the interaction energy indicates that sulfonamides are effective microbial inhibitors. Electronic SFC, SFM, SFP, and SFT descriptors agree with the experimental inhibition efficiency. The shift of the density of state (DOS) toward a low energy level for sulfonamides indicates the stabilization of these molecules at the Fe (100) surface. The population analysis combined with atomic and molecular parameters further explains the anticorrosive mechanism of sulphonamides.

The comparison of sodium sulfacetamide and erythromycin in treating trachoma

The comparison of sodium sulfacetamide and erythromycin in treating trachoma

Theoretical evaluation of C24 nanocage functionalization with protons for enhanced sulfacetamide drug delivery: A DFT study with non-covalent interaction analyses

In the realm of drug design, achieving precise and effective drug delivery poses a significant challenge. In this computational study, we explore the capacity of pristine C24 nanocages and those modified with 1H+ and 2H+ ions to serve as carriers for the sulfacetamide (SA) drug, employing density functional theory (DFT) calculations. Geometry optimizations of the SA&C24, SA&H+C24, and SA&2H+C24 complexes were conducted at the cam-B3LYP/6–31+G (d, p) level of theory. The optimized structures of all complexes exhibit local minima on the potential energy surface, indicated by the absence of imaginary frequencies, which confirms their thermodynamic stability. The negative values of adsorption energy (Eads) denote an exothermic and favorable adsorption process, with H+ ion functionalization enhancing the drug's binding affinity to the nanocages. Further analysis of the structural properties of the complexes was conducted through natural bond orbital (NBO) charge distribution, dipole moment calculations, and frontier molecular orbital analysis. Additionally, Atoms in Molecules (AIM), reduced density gradient (RDG), and electron localization function (ELF) analyses were employed to elucidate the nature of intermolecular interactions governing the drug-nanocage binding. UV-visible and nonlinear optical (NLO) response calculations reveal the potential of both pristine and functionalized C24 nanocages as optical sensors for SA drug detection. Our findings suggest that these nanocages hold promise for the development of sensitive drug delivery vehicles and targeted therapeutic agents.

Epimedium brevicornu maxim. -derived green carbon quantum dots as chemiluminescence probes for highly sensitive detection of Sulfacetamide and Sulfadimethoxine Sodium Salt

This study presented the synthesis of phosphorus (P) and chlorine (Cl) co-doped carbon quantum dots (P/Cl-CQDs) derived from Epimedium brevicornu Maxim. and established a simple and effective chemiluminescence (CL) system for detecting Sulfacetamide (STM) and Sulfadimethoxine Sodium Salt (STX). Employing traditional Chinese medicine Epimedium brevicornu Maxim. as a green precursor material, (NH4)2HPO4 and NH4Cl were utilized as dopants for P and Cl, respectively. The P/Cl-CQDs was synthesized through a one-step hydrothermal method exhibited excellent CL properties, effectively catalyzing the luminol system and markedly amplifying its CL intensity. Both STM and STX were observed to inhibit the CL intensity of the luminol-(P/Cl-CQDs) system. Based on this, a novel CL method combining flow injection technique was established for the detection of STM and STX. Under optimal conditions, the method demonstrated the capability to detect STM in the range of 1–400 × 10−6 mol/L, with a limit of detection (LOD) of 0.34 × 10−6 mol/L and a relative standard deviation (RSD) of 1.29 %, and STX within the range of 5–280 × 10−6 mol/L, with a LOD of 0.16 × 10−6 mol/L and an RSD of 1.23 %. This method successfully determined the content of STM and STX in pork, with spike recoveries ranging from 100.0 % to 103.8 % for STM and from 98.0 % to 102.3 % for STX.

Comparison of transfer of different sulphonamides from contaminated beeswax to honey.

No maximum residue limits in honey have been legislated in the EU for antimicrobial substances such as sulphonamides, and they are not permitted, therefore, for treating honey bees unless in a cascade system. Since sulphonamides are used illegally in apiculture to treat foulbrood, their residues can be found in honey and other apiculture products, including beeswax. The study aimed to assess the contamination of honey from beeswax containing residues of 10 sulphonamides (sulphadimethoxine (SDM), sulphadoxine (SDX), sulphamonomethoxine (SMM), sulphamethoxazole (SMX), sulphameter (SMT), sulphamethazine (SMZ), sulphamerazine (SMR), sulphadiazine (SDA), sulphathiazole (STZ) and sulphacetamide (SCA)). Wax-based foundations fortified with 10 sulphonamides at 10,000 μg/kg were evaluated for sulphonamide concentrations and then placed in a beehive so that honey bees (Apis mellifera L.) could build honeycombs with them. Frames of capped honey were taken out of the hives one month later and honey was sampled from them. The honeycombs were subsequently incubated in a laboratory at 35°C for five months, and honey was sampled monthly. The honey sulphonamide concentrations were measured using liquid chromatography-tandem mass spectrometry and compared to the wax-based foundation concentrations. The maximum transfers to honey of the initial amount of SDM, SDX, SMM, SMX, SMT, SMZ, SMR, SDA, STZ and SCA in the wax-based foundations were 42.6, 34.3, 31.7, 30.1, 29.5, 25.2, 18.7, 16.1, 9.5 and 8.6%, respectively. This study demonstrated that every tested sulphonamide could migrate from beeswax in antimicrobial-tainted honeycombs to honey, SDM having the highest migration potential and SCA the lowest.

Adsorption behavior and interaction mechanism of microplastics with typical hydrophilic pharmaceuticals and personal care products

Microplastics (MPs) and pharmaceuticals and personal care products (PPCPs) are two types of emerging contaminants widely present in the global aquatic ecosystem. The ecological risks associated with the coexistence of these two contaminants have garnered increasing attention from researchers. In this study, we selected 15 typical hydrophilic PPCPs, including Sulfacetamide (SA), Thiamphenicol, Florfenicol, Chloramphenicol (CHL), Ampicillin, Cephalexin, Ofloxacin, Fluorouracil, Phenytoin, Theophylline, Cimetidine, Methylparaben, Diethyltoluamide, Benzophenone-2 (BP-2), and Benzophenone-4, as adsorbates. We evaluated the adsorption potential of five traditional plastics (TPs), namely Polyamide 6 (PA6), Polystyrene (PS), Polyethylene terephthalate (PET), Polyvinyl chloride (PVC), and Polyurethane (TPU), as well as three biodegradable plastics (BDPs), including Polylactic acid (PLA), Polybutylene succinate (PBS), and Poly (ε-caprolactone) (PCL), for these adsorbates. Out of the 120 combinations of MPs and PPCPs tested, only 24 exhibited significant adsorption behavior. Notably, the adsorption performance of the three BDPs was stronger than that of the three typical TPs (PS, PET, and PVC). Based on their adsorption potential, PA6, BDPs, phenytoin, and BP-2 were identified as potential sources of high ecological risk. To further explore the adsorption mechanism, we investigated the adsorption behaviors of SA, BP-2, and CHL on PA6. The conclusions were as follows: SA, BP-2, and CHL all reached adsorption equilibrium within 24 h, with the partition coefficient (Kd) following this order: BP-2 (8.051) ≫ SA (0.052) > CHL (0.018). The primary forces of adsorption were electrostatic interactions, intermolecular hydrogen bonding, and hydrophobic interaction, respectively. Additionally, weak electrostatic effects were observed in the adsorption of CHL and BP-2. The effects of pH, ionic strength, and fulvic acid on adsorption capacity varied. These results highlight a complex adsorption mechanism between MPs and hydrophilic contaminants in the aquatic environment. This study provides a basis for further evaluating the ecological risks of MPs and PPCPs combined pollution.

Cobalt oxide nanoparticles modified coated graphite potentiometric sensor for quantification of sulfacetamide sodium in its pharmaceutical dosage form and spiked rabbit aqueous humor samples with greenness assessment

This study presents the fabrication of an innovative coated graphite electrode modified with cobalt oxide nanoparticles, for potentiometric determination of Sulfacetamide sodium. The functionalized nano-electrode was compared to a classical one; to study the advantages of addition of nanoparticles which was found to improve the performance characteristics of the electrode including improved sensitivity and selectivity, as well as, extended operational lifespan. The functionalized nano-electrode was more sensitive than the classical one with linearity range (1 × 10−7–1 × 10−2 M) and a limit of detection down to 2.24 × 10−8 M. This small modification increased the electrode’s potential stability by preventing the formation of a water layer on the surface of the solid contact electrode. The electrochemical performance of the proposed sensors was evaluated according to the IUPAC recommendation data and was found to be within the acceptable ranges. These developed potentiometric platforms were applied to quantitatively analyze Sulfacetamide sodium in its pure solutions, pharmaceutical dosage form and spiked rabbit aqueous humor with satisfactory recovery percentages without pre-extraction procedure nor interference of the co-formulated drug; Prednisolone acetate and excipients. The proposed method was statistically compared with the reported method in literature and no statistically significant difference was found. The proposed method was evaluated for its environmental sustainability utilizing the Green Analytical Procedure index (GAPI) as a greenness assessment tool.

Design of Solid-contact Ion-selective Electrode with Multiwall-carbon Nanotubes for Assay of Sulfacetamide in Rabbit Aqueous Humour

Background: Inclusion of multiwall-carbon nanotubes (MWCNTs) as ion-to-electron transducers within the ionophore-doped PVC membrane has a great impact on the stability and robustness of the produced sensor performance compared to conventional liquid-based ISEs. Objective: Solid-contact ion selective electrodes (SC-ISEs) were fabricated and optimized for the assay of sulfacetamide sodium in both ophthalmic eye drops and in rabbit aqueous humor. Methods: 2-hydroxypropyl-β-cyclodextrin (2HP-β-CD) was selected as an ionophore to dope the ionselective membrane to enhance its selectivity towards sulfacetamide. The performance of multiwall-CNTs as ion-to-electron transducer was evaluated by comparing MWCNT-based SC-ISE with control sensor which does not include the MWCNTs. The electrochemical performance characteristics of the proposed sensors were assessed in accordance with the IUPAC recommendations. A green profile assessment of the proposed method was performed using Eco-Scale and AGREES metrics. Results: Inclusion of MWCNT into the sensing membrane improved the performance of the developed sensor. The linearity range was (2.5 x 10-4 M - 1.0 x 10-2 M) for both sensors and the LOD was estimated to be 5.6 x 10-5 M for GCE/ISM(CNT) and 1.5x 10-4 M for control sensor GCE/ISM. The results of green assessment for both the developed and the official method showed an excellent greenness of the proposed method. Conclusion: The proposed sensor can be applied successfully for the determination of sulfacetamide in eye drops and rabbit aqueous humour.

Synergistic degradation of Azure B and sulfanilamide antibiotics by the white-rot fungus Trametes versicolor with an activated ligninolytic enzyme system

The treatment of complex polluted wastewater has become an increasingly critical concern for the various types of hazardous organic compounds, including synthetic dyes and pharmaceuticals. Due to their efficient and eco-friendly advantages, the white-rot fungi (WRF) have been applied to degrade environmental pollutants. This study aimed to investigate the removal ability of WRF (i.e., Trametes versicolor WH21) in the co-contamination system composed of Azure B dye and sulfacetamide (SCT). Our study discovered that the decolorization of Azure B (300 mg/L) by strain WH21 was significantly improved (from 30.5% to 86.5%) by the addition of SCT (30 mg/L), while the degradation of SCT was also increased from 76.4% to 96.2% in the co-contamination system. Transcriptomic and biochemical analyses indicated that the ligninolytic enzyme system was activated by the enhanced enzymatic activities of MnPs and laccases, generating higher concentration of extracellular H2O2 and organic acids in strain WH21 in response to SCT stress. Purified MnP and laccase of strain WH21 were revealed with remarkable degradation effect on both Azure B and SCT. These findings significantly expanded the existing knowledge on the biological treatment of organic pollutants, indicating the strong promise of WRF in the treatment of complex polluted wastewater.

Formulation development and characterization of dual drug loaded hot-melt extruded inserts for better ocular therapeutic outcomes: Sulfacetamide/prednisolone

The present investigation was intended to formulate and evaluate a hot-melt extruded (HME) bioadhesive ophthalmic inserts containing a fixed-dose combination of Prednisolone Sodium Phosphate (PSP) and Sulfacetamide Sodium (SA) to improve the treatment outcomes of multiple ocular bacterial infections. The inserts were prepared using FDA-authorised biocompatible polymers, including Polyox WSR N10 LEO NF (polyethylene oxide; PEO), Klucel™ HF (hydroxypropyl cellulose; HPC-HF), and Ethocel™ (Ethylcellulose; EC). The inserts were then assessed for physicochemical characteristics, weight variation, surface pH, uniformity of thickness, drug content, swelling index, thermal analysis, drug–excipient compatibility, moisture uptake and loss, surface morphology, mucoadhesive strength, in vitro release, ex-vivo transcorneal permeation and deposition, and stability. The HPC-HF and EC-containing inserts extended the release of both drugs compared to PEO-N10-based inserts that showed the release of the loaded amount of both drugs immediately (<1 h). All fabricated inserts were stable over 90-day storage at room temperature (25 °C) and accelerated conditions (40 °C) for drug content and thermal behavior. The developed PSP-SA inserts exhibited optimum bioadhesive strength and smooth surface favorable for topical ocular application. Ex vivo transcorneal permeation studies using freshly isolated rabbit corneas demonstrated that the extended-release inserts slowed down the transcorneal flux of the drug in comparison to the immediate-release inserts and the commercial solution eyedrops. Overall, the inserts were fabricated using a solvent-free, scalable, and continuous manufacturing process and could reduce the frequency of administration to once-daily application, affording a new topical delivery vehicle with prolonged antibacterial and anti-inflammatory activity during ocular bacterial infections treatment.

ANTIBIOTIC PRESCRIPTION AND ANTIMICROBIAL RESISTANCE RATES OF UROPATHOGENS IN CHILDREN WITH URINARY TRACT INFECTIONS

The current study aimed to evaluate the antibiotic treatment of UTIs and antimicrobial resistance of uropathogens in children with UTIs. A retrospective study was conducted in the Pediatrics Department of different centers from November 2021-November 2022. A total of 100 children with febrile or afebrile urinary tract infections were included in the study. UTIs were categorized as febrile and afebrile. Antibiotics were prescribed according to the UTI and pathogen identified. E.coli was the most common pathogen (80%) found in patients of both groups, while Citrobacter sp and gram-positive cocci were only found in one case each. Amikacin was mostly prescribed in both groups (54 for fUTIs and 8 for aUTIs). 60% of the E.coli isolates were resistant to ampicillin, 10% to AMC (amoxicillin and clavulanic acid), and 15% to SAM (Sulfacetamide sodium). The highest resistant rates of E.coli were observed against SXT, i.e., 25%. Based on the results, it can be concluded that there is a need for antimicrobial resistance stewardship programs to control the increasing prevalence of resistance among UTI-causing pathogens.

SPECTROPHOTOMETRIC METHOD FOR SIMULTANEOUS DETERMINATION OF SULPHACETAMIDE SODIUM AND PREDNISOLONE ACETATE IN OPHTHALMIC FORMULATION

A simple, precise, accurate, and rapid derivative spectrophotometric approach for the simultaneous quantification of sulfacetamide sodium (SUL) and prednisolone acetate (PRE) in the combined dosage form has been established and validated. The wavelengths selected for analysis are 230 nm (ZCP of SUL) and 244 nm (ZCP of PRE) for SUL and PRE, respectively. The suggested technique has exhibited linearity for a concentration range of 2–6 µg mL-1 for PRE and 5–15 µg mL-1 for SUL, respectively. Both medications had percentage recoveries that varied from 99.41 to 101.8. The suggested approach has been validated according to ICH guidelines [Q2(R1)] for linearity, LOD, LOQ, accuracy and precision. The proposed method can be successfully utilized to analyze SUL and PRE concurrently in ocular formulations.

Spectrophotometric Determination of Sulphacetamide Sodium Using 2,4-Dinitrophenylhydrazine as Coupling Reagent

A Sensitive, rapid and selective spectrophotometric method was developed for the determination of sulfacetamide sodium in an aqueous solution. The method is based on the oxidative coupling reaction with 2,4-dinitophenylhydrazine in the basic medium in the presence of potassium periodate to produce an intense orange colour product, soluble in water, stable and gives maximum absorbance at 484 nm. The linearity of Beer's law was in the range of 2.5-75 μg/ml of sulfacetamide. The molar absorptivity, Sandellʼs sensitivity, and detection limit were 3202.92 L/mol.cm, 0.07936 µg/cm2 and 0.50476 μg/ml respectively. This method is applied successfully to the determination of sulfacetamide in pharmaceutical preparation (eye drops and ointment).

Spectrophotometric Determination of Sulphacetamide Sodium in Its Pharmaceutical Preparations Using Azo-Coupling Reaction

Spectrophotometric Determination of Sulphacetamide Sodium in Its Pharmaceutical Preparations Using Azo-Coupling Reaction

Spectrophotometric Determination of Chlorpromazine HCl by Oxidative Coupling Method in Pharmaceutical formulations

The research includes the development of spectrophotometric method for determination microgram amounts of CPZ via oxidative coupling with the Sodium sulphacetamide reagent in presence of oxidizing agent potassium persulphate in the acidic medium (pH=1.8) to form a violet colored-dye, which is soluble in water and showed the highest intensity of absorption at λ max 550 nm. The method has been obeyed Beer's Law in the concentration range (2 - 20) µg/ml, with molar absorptivity of 1.2791 ×104 L/ mol. Cm, Sandel Index value 0.0278 µg/cm2. The detection limit 0.1727 µg/ml, with correlation coefficient 0.9983, the relative standard deviation of the method does not exceed 0.8933%, the proposed method was applied successfully for the determination of chlorpromazine hydrochloride in pharmaceutical preparation

Validated thin‐layer chromatography method for simultaneous determination of sulfacetamide sodium and hydrocortisone acetate in the ophthalmic formulation

AbstractHigh‐performance thin‐layer chromatography has the utmost separation efficiency. High‐performance thin‐layer chromatography methods can be used to separate, detect, and estimate the different phytochemicals and drug components along with additives. A simple, accurate, precise, and robust high‐performance thin‐layer chromatography method has been developed and validated for the simultaneous estimation of sulfacetamide sodium and hydrocortisone acetate in eye drops. The separation was carried out on pre‐coated silica gel aluminum plate 60 F254 as a stationary phase using ethyl acetate: toluene: methanol: triethylamine (6:2:2:0.1) as a mobile phase. The densitometric measurement of separated components was performed at 254 nm. The method was validated for accuracy, precision, reproducibility, robustness, the limit of detection, and the limit of quantification as per International Council for Harmonization (Q2[R1]) guidelines. The regression coefficients (r2) for sulfacetamide sodium and hydrocortisone acetate were found to be 0.9998 and 0.9994, respectively. The values for percentage recoveries of sulfacetamide sodium and hydrocortisone acetate were found to be 100.2%–100.9% and 101.1%–101.2%, respectively. The developed thin‐layer chromatography method can be used for the analysis of sulfacetamide sodium and hydrocortisone acetate in eye drops.

The comprehensive effects of aluminum oxide nanoparticles on the physiology of freshwater microalga Scenedesmus obliquus and it's phycoremediation performance for the removal of sulfacetamide

Nanoparticles are inevitable byproducts of modern industry. However, the environmental impacts arising from industrial applications of nanoparticles are largely under-reported. This study evaluated the ecotoxicological effects of aluminum oxide nanoparticles (Al2O3NP) and its influence on sulfacetamide (SA) biodegradation by a freshwater microalga, Scenedesmus obliquus. Although Al2O3NP showed limited toxicity effect on S. obliquus, we observed the toxicity attenuation aspect of Al2O3NP in a mixture of sulfacetamide on microalgae. The addition of 100 mg L−1 of Al2O3NP and 1 mg L−1 of SA reduced total chlorophyll by 23.3% and carotenoids by 21.6% in microalgal compared to control. The gene expression study demonstrated that ATPF0C, Lhcb1, HydA, and psbA genes responsible for ATP synthesis and the photosynthetic system were significantly downregulated, while the Tas gene, which plays a major role in biodegradation of organic xenobiotic chemicals, was significantly upregulated at 1 and 100 mg L−1 of Al2O3NP. The S. obliquus removed 16.8% of SA at 15 mg L−1 in 14 days. However, the removal was slightly enhanced (18.8%) at same concentration of SA in the presence of 50 mg L−1 Al2O3NP. This result proves the stability of sulfacetamide biodegradation capacity of S. obliquus in the presence of Al2O3NP co-contamination. The metabolic analysis showed that SA was degraded into simpler byproducts such as sulfacarbamide, sulfaguanidine, sulfanilamide, 4-(methyl sulfonyl)aniline, and N-hydroxy-benzenamine which have lower ecotoxicity than SA, demonstrating that the ecotoxicity of sulfacetamide has significantly decreased after the microalgal degradation, suggesting the environmental feasibility of microalgae-mediated wastewater technology. This study provides a deeper understanding of the impact of nanoparticles such as Al2O3NP on aquatic ecosystems.

Validated chromatographic methods for the simultaneous determination of a ternary mixture of sulfacetamide sodium and two of its official impurities; sulfanilamide and dapsone

Abstract Sulfacetamide sodium is a widely prescribed sulfonamide drug due to its topical antibacterial action on eye and skin. Four impurities are stated in the British Pharmacopoeia among which are sulfanilamide and dapsone. This work presents two specific, accurate and precise chromatographic methods for the simultaneous determination of a mixture of sulfacetamide sodium, sulfanilamide and dapsone. The first method is an isocratic RP-HPLC where the separation of components was achieved on C18 column. A green mobile phase was used consisting of methanol:water (60:40, v/v). The flow rate was 1.0 mL/min and effluent was monitored at 273 nm. The second method is a TLC-spectrodensitometric one where good separation was achieved by using silica plates and a mobile phase consisting of chloroform:dichloromethane:acetic acid (6:2.5:1.5, by volume). Determination was done by densitometry in the absorbance mode at 273 nm. Both methods were validated in compliance with ICH guidelines. They were also successfully applied for the determination of sulfacetamide sodium and its impurities in Ocusol® ophthalmic solutions. The obtained results were statistically compared to the results obtained by applying the official methods of analysis of each component where no significant difference was found with respect to accuracy and precision.

Ecotoxicological effects of sulfacetamide on a green microalga, Desmodesmus quadricauda: Cell viability, antioxidant system, and biotransformation

Sulfonamides (SAs) has been frequently found in environment with numerous adverse effects on ecological system and human. In this study, we investigated the toxicity of sulfacetamide (SFM) on a benthic microalgal species, as well as its metabolic mechanisms. Results of flow cytometry demonstrated significant inhibition on growth and cell viability of Desmodesmus quadricauda under 0.1–3 mg L−1 SFM. Half-maximum effective concentrations (EC50) of SFM were calculated to be 1.224, 1.324, 0.845, 1.178 and 1.754 mg L−1 at day 2, 4, 6, 8 and 10. Biochemical characteristics including total chlorophyll, carotenoid, malonaldehyde, and activities of antioxidant enzymes (superoxide dismutase and peroxidase) were significantly influenced by SFM. Principal component analysis showed a close correlation among the cellular contents. Moreover, identified intermediates showed that D. quadricauda can biodegrade SFM through hydroxylation, decarboxylation, bond cleavage and deamination. Acute and chronic toxicity test of the metabolic byproducts indicated the formed intermediates were with less toxicity than their parent compound. This study has extended the understanding of the microalgal tolerance and metabolic mechanisms toward SA antibiotic.