Probenecid

Synthetic Routes and Reaction Conditions: Probenecid can be synthesized through several methods. One common synthetic route involves the reaction of 4-aminobenzoic acid with dipropylamine and sulfuryl chloride to form 4-(dipropylsulfamoyl)benzoic acid. The reaction typically occurs under controlled temperature and pH conditions to ensure high yield and purity.

Industrial Production Methods: In industrial settings, this compound is produced through a similar synthetic route but on a larger scale. The process involves the use of large reactors and precise control of reaction parameters to maintain consistency and quality. The final product is purified through crystallization and filtration techniques to obtain pharmaceutical-grade this compound.

Types of Reactions: Probenecid undergoes various chemical reactions, including:

Oxidation: this compound can be oxidized to form sulfoxides and sulfones under specific conditions.

Reduction: Reduction reactions can convert this compound into its corresponding amine derivatives.

Substitution: this compound can undergo nucleophilic substitution reactions, particularly at the sulfonamide group.

Common Reagents and Conditions:

Oxidation: Common oxidizing agents include hydrogen peroxide and potassium permanganate.

Reduction: Reducing agents such as lithium aluminum hydride and sodium borohydride are used.

Substitution: Nucleophiles like amines and alcohols can react with this compound under basic conditions.

Major Products:

Oxidation: Sulfoxides and sulfones.

Reduction: Amine derivatives.

Substitution: Various substituted benzoic acid derivatives.

Pharmacological Properties

Probenecid functions primarily as a competitive inhibitor of organic acid transporters in the kidneys, which leads to increased uric acid excretion. Its pharmacokinetics reveal extensive metabolism through glucuronide conjugation and oxidation, with a half-life ranging from 4 to 12 hours depending on dosage .

Table 1: Pharmacokinetic Profile of this compound

Antiviral Applications

Recent studies have highlighted this compound's potential as an antiviral agent, particularly against SARS-CoV-2. In vitro and in vivo studies demonstrated that this compound significantly reduces viral replication in hamster models, achieving a 4-5 log reduction in lung virus titers compared to controls . The drug's ability to inhibit the NLRP3 inflammasome pathway further supports its role in modulating inflammatory responses during viral infections.

Table 2: Efficacy of this compound Against SARS-CoV-2

Neurological Applications

This compound has gained attention for its neuroprotective properties. It interacts with various membrane proteins, such as TRPV2 channels and pannexin-1 hemichannels, suggesting potential therapeutic uses in neurodegenerative diseases . Studies indicate that it can enhance the bioavailability of neurotransmitter metabolites, which may be beneficial in treating conditions like depression and epilepsy.

Table 3: Neuroprotective Effects of this compound

Case Study 1: Cardiovascular Risks

A study comparing this compound to allopurinol indicated that this compound treatment was associated with a lower risk of cardiovascular events, such as myocardial infarction and stroke, particularly among older patients . This suggests that this compound may offer additional benefits beyond its traditional uses.

Case Study 2: Influenza Treatment

Research on this compound's role in influenza treatment revealed that it could reduce disease severity by modulating cytokine production and enhancing the efficacy of neuraminidase inhibitors like oseltamivir . This positions this compound as a valuable adjunct therapy in managing influenza infections.

Probenecid exerts its effects by inhibiting the organic anion transporters (OAT) in the renal tubules . This inhibition reduces the reabsorption of uric acid, leading to increased excretion in the urine and decreased serum uric acid levels . This compound also inhibits pannexin 1 channels, which are involved in the activation of inflammasomes and the release of interleukin-1β, thereby reducing inflammation .

Allopurinol: Used to reduce uric acid production by inhibiting xanthine oxidase.

Febuxostat: Another xanthine oxidase inhibitor used to lower uric acid levels.

Sulfinpyrazone: A uricosuric agent similar to probenecid but with different pharmacokinetic properties.

Comparison:

This compound vs. Allopurinol: this compound increases uric acid excretion, while allopurinol reduces its production.

This compound vs. Febuxostat: Both are used to manage hyperuricemia, but febuxostat is more potent and has a different mechanism of action.

This compound vs. Sulfinpyrazone: Both are uricosuric agents, but this compound has a longer half-life and is more commonly used in clinical practice.

This compound’s unique ability to inhibit renal excretion of various drugs makes it a valuable tool in both clinical and research settings, distinguishing it from other similar compounds.

Probenecid, a uricosuric agent primarily used in the treatment of gout, has garnered attention for its diverse biological activities beyond its original therapeutic indications. This article explores the multifaceted biological activities of this compound, including its effects on drug transport, antiviral properties, and potential therapeutic applications in various medical conditions.

This compound functions primarily as an inhibitor of various organic anion transporters (OATs) and multidrug resistance-associated proteins (MRPs). Notably, it inhibits OAT3, which plays a crucial role in the renal excretion of drugs and metabolites. This inhibition can enhance the bioavailability of certain medications by reducing their renal clearance. Additionally, this compound has been shown to inhibit pannexin 1 (Panx1) channels, which are involved in cellular signaling processes.

Antiviral Activity

Recent studies have highlighted this compound's potent antiviral properties, particularly against SARS-CoV-2 and influenza A viruses.

• SARS-CoV-2 : this compound demonstrated an in vitro IC50 of 1.3 nM in NHBE cells and 750 nM in Vero E6 cells, significantly reducing lung virus titers in animal models .
• Influenza A : It also exhibited inhibitory effects on influenza A virus replication both in vitro and in vivo .

Cardiovascular Implications

A significant body of research has investigated this compound's effects on cardiovascular health. A study involving nearly 10,000 patients indicated that this compound was associated with a 20% reduction in the risk of myocardial infarction (MI) or stroke compared to allopurinol . The findings suggested that this compound could potentially improve outcomes for patients with cardiovascular conditions.

Neuroprotective Effects

This compound's ability to interact with TRPV2 channels and OATs suggests potential neuroprotective effects. It has been shown to reduce neuroinflammation by blocking Panx1 hemichannels, which may be beneficial in treating neurological disorders . Studies have indicated that this compound can increase brain levels of kynurenate, a neuroprotective metabolite, thereby enhancing its therapeutic potential against neurodegenerative diseases.

Pharmacokinetic Enhancements

This compound is frequently used as an adjuvant therapy to enhance the pharmacokinetics of various antibiotics. For instance:

• β-lactam antibiotics : Co-administration with this compound has been shown to increase the area under the curve (AUC) and peak serum concentrations (Cmax) of drugs like flucloxacillin and cefalexin, improving their efficacy against bacterial infections .
• Antibiotic Resistance : Meta-analyses have demonstrated that this compound can significantly reduce treatment failure rates in gonococcal disease when used alongside β-lactam antibiotics .

Case Study 1: Cardiac Function Improvement

In a clinical trial assessing this compound's effects on heart failure patients, it was found to improve diastolic function and increase myofilament force generation without significant adverse effects .

Case Study 2: Antiviral Efficacy

In a phase 2 study evaluating this compound's antiviral activity against mild COVID-19, it was observed to significantly reduce viral loads when administered either prophylactically or post-infection .

Summary Table of Biological Activities

Basic Research Questions

Q. What methodological considerations are critical when developing UV-Vis spectroscopic techniques for quantifying Probenecid in pharmacokinetic studies?

• Answer : Key steps include selecting optimal wavelengths (e.g., λ~max~ of this compound in solvent systems), validating linearity over a concentration range (e.g., 2–20 µg/mL), and assessing precision (intra-day/inter-day %RSD <2%). Matrix effects from bulk drugs or formulations must be minimized using solvent extraction or dilution. Validation parameters (accuracy, specificity, robustness) should adhere to ICH guidelines .

Q. How can researchers design clinical studies to evaluate this compound's urate-lowering efficacy in gout patients with renal impairment?

• Answer : Retrospective cohort studies should stratify patients by eGFR (e.g., <50 vs. ≥50 mL/min/1.73 m²) and use logistic regression to identify predictors of serum urate (SU) target achievement (e.g., baseline SU, dose adjustments). Exclude confounding factors like co-medications or non-adherence. SU measurements should be standardized post-treatment (≥1 month at maximum dose) .

Q. What experimental protocols are recommended to assess this compound's inhibition of organic anion transporters (OATs) in drug-drug interaction studies?

• Answer : Use in vitro assays (e.g., HEK293 cells expressing OAT3 or OATP1B1) with competitive inhibition constants (K~i~) derived from this compound co-incubation. Validate findings via compartmental pharmacokinetic modeling to predict interactions with substrates like ciprofloxacin. Adjust for saturable metabolite formation and non-renal clearance assumptions .

Advanced Research Questions

Q. What strategies address contradictions in this compound's transporter-mediated pharmacokinetics when in vitro and clinical data are limited?

• Answer : Optimize passive transcellular permeability (e.g., 3.97 × 10⁻⁶ cm/min vs. lipophilicity-based predictions) in physiologically-based pharmacokinetic (PBPK) models. Incorporate inhibition constants (K~i~) for OAT3, UGT1A9, and MRP4 from sparse in vitro data. Validate models against historical clinical studies, excluding non-standard formulations or co-medications .

Q. How can researchers resolve conflicting data on this compound's efficacy in chronic kidney disease (CKD) populations?

• Answer : Conduct subgroup analyses stratified by eGFR (e.g., 30–50 mL/min/1.73 m²). Use multivariate regression to isolate this compound's effect from confounders (e.g., allopurinol use). Monitor SU reduction thresholds (<0.36 mmol/L) and adverse events, adjusting for renal clearance variability. Note that eGFR is not an independent predictor of SU target failure in moderate CKD .

Q. What experimental approaches validate this compound's inhibition of osteoclastogenesis via reactive oxygen species (ROS) and downstream signaling pathways?

• Answer : Treat RAW264.7 cells with LPS to induce ROS, then dose with this compound (e.g., 10–100 µM). Quantify ROS via fluorescence assays (DCFH-DA) and validate via Western blot for phosphorylated JNK (pJNK) and COX-2 expression. Dose-response curves (IC₅₀) should confirm pathway-specific inhibition .

Q. How do physiologically-based pharmacokinetic (PBPK) models integrate transporter inhibition data to predict this compound-drug interactions?

• Answer : Incorporate optimized inhibition constants (K~i~) for OAT3, MRP4, and OATP1B1 into PBPK software (e.g., Simcyp®). Simulate competitive inhibition of renal secretion (e.g., ciprofloxacin) and adjust for inter-individual variability in transporter expression. Validate against clinical AUC changes (e.g., ciprofloxacin + this compound) .

Q. What statistical methods are appropriate for analyzing this compound's dose-response relationships in heterogeneous patient cohorts?

• Answer : Use mixed-effects models to account for repeated measures (e.g., SU levels over time) and covariates (e.g., eGFR, ethnicity). Non-linear regression can identify threshold doses (e.g., 1.1–1.2 g/day) for SU target achievement. Sensitivity analyses should address adherence biases in retrospective data .

Q. How can researchers address the lack of in vivo transporter data for this compound in PBPK model development?

• Answer : Assume transporter-mediated absorption/distribution based on low solubility/permeability (Biopharmaceutics Classification System IV). Use in vitro-in vivo extrapolation (IVIVE) for intestinal permeability and optimize kidney uptake parameters (e.g., partition coefficients) against clinical PK profiles .

Q. What mechanisms underlie this compound's anti-inflammatory effects beyond urate-lowering, and how can they be experimentally validated?

• Answer : Investigate ROS scavenging in macrophage lineages (e.g., THP-1 cells) via flow cytometry. Use siRNA knockdown of JNK/COX-2 to confirm pathway necessity. In vivo models (e.g., murine gout) can correlate ROS inhibition with reduced joint inflammation .

Q. Methodological Notes

• Data Contradictions : Retrospective studies may overestimate efficacy due to selection bias (e.g., exclusion of non-adherent patients). Address via propensity score matching .
• Advanced Techniques : Compartmental modeling outperforms non-compartmental analysis (NCA) in predicting dose-dependent interactions .
• Clinical Relevance : this compound remains viable in mild-moderate CKD but requires SU monitoring due to variable renal clearance .