Allopurinol

Primary Mechanism: Xanthine Oxidase Inhibition

Xanthine oxidoreductase (XOR) is a key enzyme in the catabolism of purines. It exists in two interconvertible forms: xanthine dehydrogenase (XDH) and xanthine oxidase (XO). Both forms catalyze the oxidation of hypoxanthine to xanthine and xanthine to uric acid. researchgate.netnih.govresearchgate.net Allopurinol and its main metabolite, oxypurinol, are potent inhibitors of XOR, thereby blocking the final steps in uric acid synthesis. drugbank.compatsnap.com

Secondary and Pleiotropic Mechanisms of this compound

Absorption and Bioavailability of Allopurinol

This compound is rapidly and extensively absorbed from the gastrointestinal tract following oral administration researchgate.netmedsafe.govt.nz. Absorption primarily occurs in the upper gastrointestinal tract biomedpharmajournal.org. Studies have detected this compound in the blood within 30-60 minutes after dosing biomedpharmajournal.org. Peak plasma concentrations of this compound typically occur around 1.5 hours post-oral administration drugbank.combiomedpharmajournal.orgmedsafe.govt.nz. Estimates of oral bioavailability range from 67% to 90% researchgate.netresearchgate.netbiomedpharmajournal.org. Some limited data suggest the possibility of dose-dependent bioavailability, although further research is needed in this area researchgate.net. Following a single oral dose of 300 mg, maximum plasma levels of approximately 3 mcg/mL for this compound and 6.5 mcg/mL for oxypurinol have been measured drugbank.com. Rectal absorption of this compound is extremely limited and is not a recommended route of administration researchgate.net.

Distribution of this compound and its Metabolites within Tissues

This compound is uniformly distributed throughout total tissue water, with the exception of the brain, where concentrations are approximately 50% of those in other tissues medsafe.govt.nzmedcentral.comnps.org.au. This compound and its metabolite, oxypurinol, are negligibly bound to plasma proteins drugbank.comresearchgate.netmedsafe.govt.nzmedcentral.comnps.org.au. Both compounds are distributed into breast milk medsafe.govt.nzmedcentral.comnps.org.au. While tissue concentrations of this compound in humans have not been widely reported, it is likely that this compound and oxypurinol are present in highest concentrations in tissues rich in xanthine oxidase, such as the liver and intestinal mucosa drugbank.comresearchgate.net. In animal studies, this compound concentrations were found to be highest in blood, liver, intestine, and heart, and lowest in brain and lung tissues drugbank.comresearchgate.net. Small amounts of this compound and oxypurinol crystals have been detected in muscle tissue medsafe.govt.nzmedcentral.comnps.org.au.

Metabolism of this compound, Including Hepatic Transformation to Oxypurinol

This compound is rapidly converted to its principal pharmacologically active metabolite, oxypurinol (alloxanthine), in the body drugbank.comresearchgate.netmedsafe.govt.nzmedcentral.comnps.org.aud-nb.info. This biotransformation primarily occurs in the liver drugbank.comnih.gov. The conversion of this compound to oxypurinol is catalyzed by xanthine oxidase (XO) and aldehyde oxidase (AO) d-nb.infopharmgkb.orgnih.gov. While both enzymes contribute, aldehyde oxidase may have a proportionately greater impact on this compound metabolism at high this compound concentrations nih.govresearchgate.net. The rapid metabolism of this compound to oxypurinol does not appear to be substantially affected by liver impairment medcentral.com. Other metabolites, including this compound riboside and oxypurinol-7-riboside, are also formed medsafe.govt.nznps.org.aupharmgkb.org.

Aldehyde oxidase (AO) plays a significant role in the metabolism of this compound to oxypurinol researchgate.netnih.govresearchgate.net. Along with xanthine oxidase (XO), AO catalyzes this conversion d-nb.infopharmgkb.orgnih.gov. Research indicates that individual differences in AO activity may contribute to variations in this compound metabolism and potentially explain toxicity events nih.govresearchgate.net. Studies in rats have shown that AO can have a greater impact on this compound metabolism at higher concentrations nih.govresearchgate.net. Both AO and XO can metabolize this compound to oxypurinol through a self-inhibitory mechanism researchgate.net.

Elimination of this compound and Oxypurinol

This compound and its metabolites are primarily eliminated by the kidneys drugbank.commims.commedsafe.govt.nznps.org.aud-nb.infonih.gov. Approximately 80% of an orally administered dose of this compound is recovered in the urine within 24 hours, mainly in the form of oxypurinol researchgate.netmedsafe.govt.nz. About 5-7% of an oral dose is excreted unchanged in the urine within 6 hours medcentral.com. Approximately 20% of ingested this compound is excreted in the feces as unchanged drug drugbank.commedsafe.govt.nzmedcentral.comnps.org.au.

This compound has a relatively short plasma half-life of about 1-3 hours due to its rapid renal clearance and metabolism drugbank.comresearchgate.netnih.govmedsafe.govt.nzmedcentral.com. In contrast, oxypurinol has a significantly longer elimination half-life, ranging from approximately 15 to 30 hours in patients with normal renal function researchgate.netnih.govmedsafe.govt.nzmedcentral.com. This longer half-life of oxypurinol is crucial as it maintains effective xanthine oxidase inhibition over a 24-hour period with single daily dosing of this compound medsafe.govt.nz.

While this compound is cleared essentially by glomerular filtration, oxypurinol undergoes significant tubular reabsorption in the kidneys, similar to uric acid medsafe.govt.nzmedcentral.com. This reabsorption contributes to its lower renal clearance compared to this compound medcentral.com. Renal clearance of oxypurinol is approximately 30 ml/min researchgate.net. In patients with impaired renal function, the elimination half-life of oxypurinol is prolonged, leading to its accumulation drugbank.comresearchgate.netnih.govmedcentral.comnps.org.au. Both this compound and oxypurinol are dialyzable nih.govmedcentral.com.

Pharmacodynamic Effects on Uric Acid and Oxypurine Levels

This compound and its active metabolite, oxypurinol, exert their pharmacodynamic effects by inhibiting xanthine oxidase (XO), the enzyme responsible for the conversion of hypoxanthine to xanthine and xanthine to uric acid drugbank.comwikipedia.orgresearchgate.netnih.govmedcentral.com. By blocking these steps in the purine catabolism pathway, this compound therapy leads to a decrease in serum and urinary uric acid concentrations drugbank.commims.commedsafe.govt.nzmedcentral.com.

Accompanying the reduction in uric acid levels is an increase in the serum and urine concentrations of the oxypurines, hypoxanthine and xanthine drugbank.commedcentral.com. In the absence of this compound, urinary excretion of oxypurines primarily occurs as uric acid drugbank.com. After this compound administration, the excreted urine contains hypoxanthine, xanthine, and uric acid drugbank.com. While levels of hypoxanthine and xanthine increase, the risk of their deposition in renal tissues is lower than that of uric acid due to their greater solubility and rapid renal excretion drugbank.com. The renal clearance of hypoxanthine and xanthine is at least 10 times greater than that of uric acid medsafe.govt.nzmedcentral.com.

The reduction in serum uric acid concentrations typically begins within 24-48 hours of initiating this compound therapy and reaches a nadir after 1-3 weeks medcentral.com. This compound also has an additional action of reducing de novo purine biosynthesis, thought to occur as a consequence of feedback inhibition of amidophosphoribosyl transferase, the rate-limiting enzyme in purine biosynthesis researchgate.netresearchgate.net. This feedback inhibition is also influenced by the increased reutilization of hypoxanthine and xanthine for nucleotide and nucleic acid synthesis via the purine salvage pathway drugbank.comresearchgate.net.

Pharmacokinetic/Pharmacodynamic Modeling Approaches for this compound

Pharmacokinetic/pharmacodynamic (PK/PD) modeling approaches have been employed to characterize the relationship between this compound and oxypurinol concentrations and their effects on uric acid and oxypurine levels d-nb.infonih.govhelsinki.firesearchgate.net. These models often describe the pharmacokinetics of this compound and oxypurinol using compartmental models, linking them to pharmacodynamic models that represent the turnover of hypoxanthine, xanthine, and uric acid and the inhibition of xanthine oxidase d-nb.infonih.govhelsinki.firesearchgate.net.

Studies utilizing nonlinear mixed-effects modeling have described the PK of this compound and oxypurinol using sequential one-compartment models, sometimes incorporating an auto-inhibition effect of oxypurinol on this compound metabolism nih.govhelsinki.firesearchgate.net. These models estimate parameters such as clearance and volume of distribution for both this compound and oxypurinol nih.govhelsinki.firesearchgate.net. For instance, in a study involving neonates, typical clearance values for this compound and oxypurinol were estimated, with oxypurinol clearance being relative to a formation fraction nih.govhelsinki.firesearchgate.net. PK/PD models have also been used to evaluate target attainment of specific this compound concentrations and their corresponding effects on XO inhibition and uric acid levels d-nb.infonih.govhelsinki.fi. The combined concentration of this compound and oxypurinol at which half-maximal XO inhibition occurs has been estimated through these modeling approaches d-nb.infonih.govhelsinki.fi.

Pharmacokinetic Parameters (Example from Literature)

Note: Data presented are representative examples from the cited literature and may vary depending on the specific study population and methodology.

Pharmacodynamic Effects on Purine Metabolism (Conceptual)

Effects on Hypoxia Inducible Factor (HIF) System and Angiogenesis

Studies have investigated the effects of allopurinol on the Hypoxia Inducible Factor (HIF) system, a key regulator of cellular responses to hypoxia. High doses of this compound have been shown to reduce the accumulation of HIF-1α protein in human foreskin fibroblasts (HFF) and human umbilical vein endothelial cells (HUVEC) under both normoxic and hypoxic conditions plos.orgnih.govresearchgate.net. This reduction in HIF-1α protein levels appears to be independent of prolyl-hydroxylase activity and has only marginal effects on HIF-1α mRNA levels plos.orgnih.gov.

Furthermore, this compound treatment has been observed to reduce angiogenesis traits in HUVEC cells in in vitro models plos.orgnih.gov. This suggests that this compound may inhibit pro-angiogenic processes in cells, potentially through its influence on the HIF system.

Data on this compound's Effect on HIF-1α Protein Levels and Angiogenesis Traits:

Impact on Cellular Proliferation and Energy Metabolism

This compound's impact on cellular proliferation and energy metabolism has been explored in various cellular contexts. In the context of experimental colitis, a therapeutically relevant dose of this compound was found to disrupt purine metabolism, leading to shifts in adenylate and creatine metabolism nih.govnih.govresearchgate.net. This metabolic alteration resulted in the dysregulation of AMP-activated protein kinase (AMPK) nih.govnih.govresearchgate.net.

The dysregulation of AMPK was associated with disrupted proliferation in intestinal epithelial cells, contributing to attenuated wound healing and increased tissue damage in murine experimental colitis nih.govnih.govresearchgate.net. In vitro studies using T84 intestinal epithelial cells treated with this compound revealed that it can impede ATP production and energy distribution through its influence on the creatine kinase circuit nih.govresearchgate.net. While some doses showed no significant difference in intracellular AMP or ADP, a higher dose increased phosphocreatine levels nih.govresearchgate.netresearchgate.net.

In a study involving colorectal adenoma, this compound did not significantly influence Ki-67 levels, a marker of cellular proliferation aacrjournals.org. However, it did blunt the increase in β-catenin and NF-κB levels in adenomatous tissue, suggesting an influence on pathways related to cellular growth and inflammation, although the effect on proliferation marker Ki-67 was not statistically significant aacrjournals.org.

Data on this compound's Impact on Proliferation and Metabolism:

Modulation of Inflammatory Mediators and Cytokines

This compound has been shown to modulate inflammatory mediators and cytokines in various contexts. Its anti-inflammatory properties have been suggested as a reason for its use in inflammatory bowel disease aacrjournals.org.

Studies have indicated that this compound can mitigate T cell activation, evidenced by decreased CD69 expression and diminished secretion of IL-2 and IFN-γ following antigen stimulation frontiersin.orgfrontiersin.org. This suggests a direct action of this compound on human T cells, potentially offering a therapeutic tool for cell-mediated inflammatory diseases frontiersin.org.

In avian studies, reduced urate levels due to this compound treatment were linked to an increase in the expression of pro-inflammatory cytokines such as IL-6, COX-2, and TNF-α in the intestines of female chickens wvu.eduwvu.edu. TNF-α expression, however, decreased in the liver of both female and male chickens wvu.eduwvu.edu. This indicates that the modulation of inflammatory mediators by this compound can be tissue-specific and potentially influenced by biological sex.

This compound treatment has also been shown to decrease NF-κB expression levels in adenomatous and normal adjacent colorectal tissue, a key transcription factor involved in inflammatory responses aacrjournals.org.

Data on this compound's Modulation of Inflammatory Mediators and Cytokines:

Influence on Epithelial Cell Function and Metabolism in Gastrointestinal Tissues

Research has explored this compound's influence on epithelial cell function and metabolism, particularly in the gastrointestinal tract. As mentioned earlier, in experimental colitis, this compound disrupted purine metabolism in colonic epithelial cells, affecting adenylate and creatine metabolism and leading to AMPK dysregulation nih.govnih.govresearchgate.net. This metabolic shift was associated with impaired epithelial proliferation and wound healing nih.govnih.govresearchgate.net.

In vitro studies using intestinal epithelial cells demonstrated that this compound can impede ATP production and influence the creatine kinase circuit nih.govresearchgate.netresearchgate.net. These findings highlight the importance of purine salvage for cellular metabolism and gut health nih.govnih.govresearchgate.net.

Furthermore, in avian studies, this compound treatment was suggested to induce cellular remodeling of the intestines and generate an inflammatory state, potentially due to the upregulation of IL-6, COX-2, and TNF-α wvu.edu. This was also linked to an increase in intestinal permeability wvu.edu.

Data on this compound's Influence on Gastrointestinal Epithelial Cells:

Pharmacogenomics of Allopurinol Response and Adverse Reactions

Pharmacogenomics plays a crucial role in understanding the variability in patient responses to this compound and the risk of developing adverse reactions. Genetic factors, particularly variations in human leukocyte antigen (HLA) genes, have been strongly associated with the incidence of severe cutaneous adverse reactions (SCARs).

Mechanisms of this compound Resistance

While this compound is effective for many patients, some individuals exhibit an inadequate response to treatment, failing to achieve the target serum urate levels necessary for effective gout management. This inadequate response can be considered a form of "partial resistance" in adherent patients receiving appropriate doses. nih.govnih.govpharmgkb.org

Drug Interactions and Associated Biochemical Mechanisms

This compound's inhibitory effect on xanthine oxidase can lead to significant drug interactions, particularly with medications that are metabolized by this enzyme.

Effects of Allopurinol on T-Cell Activation and Cytokine Production

Research indicates that this compound can modulate the activation and cytokine production of T lymphocytes. Studies have shown that this compound can mitigate T cell activation following stimulation, evidenced by decreased expression of CD69 and reduced secretion of cytokines such as IL-2 and IFN-γ. frontiersin.orgfrontiersin.orgnih.govnih.gov IL-2 is a cytokine crucial for driving T cell activation, while IFN-γ is a key effector cytokine of Th1 cells. frontiersin.orgnih.gov This suggests that this compound may have a direct action on human T cells, potentially serving as a pharmacological tool for managing cell-mediated inflammatory diseases. frontiersin.orgnih.govnih.gov

This compound has been shown to decrease the frequency of IFN-γ and IL-2-producing T cells after both polyclonal and antigen-specific stimulation with various antigens, including Herpes Simplex virus 1, Influenza virus, tetanus toxoid, and Trypanosoma cruzi-derived antigens. nih.govnih.govyork.ac.uk Furthermore, it has been observed to attenuate CD69 upregulation after engagement of CD3 and CD28, which mimics signals generated by the T cell receptor complex. frontiersin.orgnih.govnih.govyork.ac.ukresearchgate.net This attenuation supports the notion of a direct action of this compound on T cells, bypassing the need for T cell-antigen presenting cell interaction. nih.gov

In experimental models of autoimmune uveitis (EAU), this compound demonstrated significant immunomodulating effects, influencing the immunologic mechanism in this model of autoimmune disease. researchgate.netnih.gov These effects were detected even when therapy was initiated after the onset of the disease. researchgate.netnih.gov

Modulation of B-Cell Responses

Studies in animal models have explored this compound's influence on B-cell responses. In normal BALB/c mice, long-term administration of this compound resulted in a decreased immune response to ovalbumin in the peripheral blood. researchgate.netnih.gov This decreased response was suggested to be potentially due to direct B cell suppression or suppression of helper T cell function. researchgate.netnih.gov In severe combined immunodeficient (SCID) mice, this compound administration led to a markedly late and reduced recovery of surface immunoglobulin (sIg) positive cells, which are markers for mature B lymphocytes, in the peripheral blood. researchgate.netnih.gov Additionally, total immunoglobulin G (IgG) titers were significantly lower in the this compound-treated group at certain time points compared to controls, suggesting that this compound may modulate B cell responses in antigen-immunized antibody formation. researchgate.netnih.gov

Role in Oxidative Stress and Reactive Oxygen Species Scavenging in Immune Responses

This compound is known for its ability to inhibit xanthine oxidase, an enzyme that contributes to the production of reactive oxygen species (ROS), such as superoxide and hydrogen peroxide, during the metabolism of purines. nih.gov Beyond this inhibitory action, this compound and its metabolite oxypurinol have been shown to act as direct free radical scavengers and antioxidants. frontiersin.orgresearchgate.netresearchgate.net

In the context of immune responses, oxidative stress plays a significant role in inflammation and cell activation. This compound has been shown to significantly reduce levels of spontaneous and mitogen-induced intracellular reactive oxygen species in T cells. frontiersin.orgnih.govnih.govyork.ac.ukresearchgate.net This scavenging action during early T cell activation events could partially explain its effect on diminishing T cell activation. frontiersin.org

Research in various inflammatory models has demonstrated that this compound can reduce oxidative stress. frontiersin.orgnephropathol.complos.orgaacrjournals.org For instance, in a model of global brain ischemia-reperfusion injury, this compound reduced mRNA levels of pro-inflammatory cytokines, cell surface molecules, and enzymes, with its neuroprotective effect suggested to be derived from a direct free-radical-scavenging effect rather than solely from xanthine oxidoreductase inhibition. plos.org In experimental lens-induced uveitis, higher doses of this compound were able to reduce oxidative damage, suggesting an effect due to its free radical scavenging and antioxidative activity generated by activated leukocytes. researchgate.net

The chronic inflammatory microenvironment in conditions like colon cancer is characterized by elevated levels of ROS. aacrjournals.org this compound's ability to decrease ROS production has been observed in animal models. aacrjournals.org

This compound's Influence on Gut Microbiota and Systemic Immune Effects

Emerging research suggests a complex interplay between this compound, the gut microbiota, and systemic immune effects. The gut microbiota plays a vital role in host metabolism and immune regulation, and imbalances have been associated with metabolic disorders and the release of inflammatory cytokines. frontiersin.org

Studies have indicated that this compound treatment can lead to changes in the composition of the gut microbiota. In a hyperuricemia rat model, this compound treatment resulted in increased abundance of Bifidobacterium and Collinsella, and decreased abundance of Adlercreutzia and Anaerostipes. frontiersin.orgclinexprheumatol.org Another study noted an increase in Bifidobacterium and a decrease in anaerobes in the gut microbiota following this compound treatment. wjgnet.comnih.gov Notably, this compound treatment was also associated with a significant decrease in Bilophila, a genus linked to systemic inflammation. frontiersin.orgwjgnet.comnih.gov These alterations in gut microbiota composition suggest that this compound's therapeutic effects, particularly in conditions like gout, may involve the modulation of the intestinal microbial environment. frontiersin.orgwjgnet.com

Furthermore, metabolites generated by intestinal microbes can influence host gene expression in various tissues, including the brain, suggesting a pathway for microbiota to influence the central nervous system activity. wvu.edu While some studies in avian models suggest that this compound administration can potentially evoke type 1 immune reactions via IL-6 by altering the intestinal environment, the relationship between reduced urate levels, the immune system, and the pathogenesis of the intestine, liver, or brain is not fully characterized across different species. wvu.eduwvu.edu

Potential in Cell-Mediated Inflammatory Diseases

The observed effects of this compound on T cell activation, cytokine production, and oxidative stress suggest its potential as a therapeutic tool for managing cell-mediated inflammatory diseases. frontiersin.orgnih.govnih.gov By diminishing T cell activation and cytokine production, this compound may help to attenuate the inflammatory responses driven by these cells. frontiersin.orgnih.govnih.gov

The suppression of IFN-γ production in T lymphocytes by this compound, as indicated by research, may contribute to its potential in attenuating cell-mediated inflammatory diseases. frontiersin.org Experimental models of autoimmune diseases, such as experimental autoimmune uveitis, have shown significant immunomodulating effects of this compound, further supporting its potential in this area. researchgate.netnih.gov

While research into the anti-inflammatory effects of this compound in specific conditions like prostate cancer has yielded mixed results, its established anti-inflammatory properties and effects on oxidative stress highlight its relevance in the broader context of inflammatory processes. researchgate.netnih.govtouro.edu The ability of this compound to inhibit biomarkers of oxidative activation in tissues like colon adenomatous polyps also points towards its potential in influencing inflammatory pathways involved in disease development. aacrjournals.org

Neuroprotective Effects and Mechanisms in Neurological Conditions

Research is exploring the neuroprotective potential of allopurinol in various neurological conditions. While the precise mechanisms are still under investigation, they are thought to involve the reduction of oxidative stress and inflammation, processes implicated in neurodegeneration.

Potential in Cardiovascular Disease Beyond Urate Lowering

Beyond its effect on uric acid, this compound is being investigated for its potential benefits in cardiovascular disease. Studies suggest mechanisms that may contribute to cardiovascular protection, such as improving endothelial function, reducing oxidative stress, and modulating inflammatory pathways.

Investigation in Chronic Kidney Disease

This compound's role in chronic kidney disease (CKD) is another area of active research. While hyperuricemia is often associated with CKD, studies are investigating whether this compound's effects, potentially through reducing oxidative stress and inflammation, can directly impact kidney function and slow disease progression, independent of uric acid lowering.

Role in Inflammatory Bowel Disease and Colitis

The potential therapeutic application of this compound in inflammatory bowel disease (IBD) and colitis is being explored. Research suggests that its anti-inflammatory and antioxidant properties may play a role in ameliorating intestinal inflammation.

Exploration in Psychiatric Disorders

This compound is being investigated as a potential adjunctive treatment for certain psychiatric disorders, including schizophrenia and major depressive disorder. researchgate.netjournalijar.com The proposed mechanisms involve the modulation of purinergic neurotransmission and increasing tryptophan levels, a precursor to serotonin. journalijar.compsychiatrist.com Clinical studies in schizophrenia have shown mixed results, with some trials indicating improvement in psychotic symptoms and cognitive problems, while others have been inconclusive. journalijar.com In major depressive disorder, studies suggest that this compound adjunct to standard treatment may provide better therapeutic effects and improve associated mental health disorders. This effect is hypothesized to be linked to increased tryptophan levels due to xanthine oxidase inhibition. A case report also provides evidence supporting the use of this compound as an adjunctive therapy in managing severe mania, particularly in cases with comorbid gout. psychiatrist.com The mechanism here is thought to involve the influence on purinergic neurotransmission and elevated brain adenosine levels due to xanthine oxidase inhibition, indirectly affecting dopamine binding. psychiatrist.compsychiatrist.com

Here is a summary of findings in psychiatric disorders:

Anticancer Research and Tumorigenesis Modulation

Research is exploring the potential of this compound in anticancer strategies and its role in modulating tumorigenesis. Investigations are focusing on its ability to inhibit xanthine oxidase, which can influence cellular processes relevant to cancer development and progression.

Other Investigational Therapeutic Areas and Underlying Mechanisms

Beyond the specific areas mentioned, this compound is being investigated in other therapeutic areas. The underlying mechanisms in these diverse applications often relate to its primary function as a xanthine oxidase inhibitor, leading to reduced uric acid production and consequently mitigating oxidative stress and inflammation. These effects can have broad implications in various disease states where oxidative damage and inflammation play a significant role.

In Vitro and In Vivo Models for Studying Allopurinol

In vitro models provide a controlled environment to investigate the direct effects of this compound on cells and biological processes. These models are valuable for elucidating the molecular mechanisms underlying this compound's actions, such as its inhibition of xanthine oxidase and its effects on cellular pathways. For instance, in vitro studies have explored the dose-dependent effects of this compound on human foreskin fibroblasts (HFF) and human umbilical vein endothelial cells (HUVEC) under hypoxic conditions, demonstrating that high doses can reduce the accumulation of HIF-1α protein and inhibit angiogenesis traits in HUVEC cells plos.org. Another in vitro approach utilized cultured human kidney cells (HK-2 cells) to establish a model for high uric acid production, which was then used to verify the antihyperuricemic effect of this compound nih.gov. This cell model, induced by adenosine, allows for the screening of compounds that reduce uric acid production and mimics in vivo cell growth patterns nih.gov. Furthermore, in vitro studies have investigated the effect of this compound on antigen-specific and polyclonal activation of human T cells, showing that it can decrease the frequency of IFN-γ and IL-2-producing T cells after stimulation frontiersin.org.

In vivo models, typically involving animal subjects, are crucial for studying the systemic effects of this compound, its pharmacokinetics and pharmacodynamics, and its efficacy in complex biological systems that mimic disease states. Various animal models have been utilized in this compound research. For example, a mouse model of postischemic cardiomyopathy was used to demonstrate that chronic this compound treatment improved survival and cardiac contractility ahajournals.org. In this model, this compound suppressed elevated cardiac xanthine oxidase activity and prevented oxidative modifications to proteins ahajournals.org. Chickens have also been proposed as a suitable animal model for studying hyperuricemia and gout due to their purine-urate metabolic pathway, and studies in this model have shown that this compound can decrease serum urate levels mdpi.com. Rat models have been employed to investigate the potential of this compound-loaded hydrogels for intervertebral disk regeneration, showing promising results in promoting repair bjbms.org. Additionally, animal models of crystal-induced inflammation, often involving the injection of monosodium urate (MSU) crystals into joints, are used to study gouty arthritis and the effects of treatments like this compound windows.netnews-medical.net. While MSU crystals activate the NALP3 inflammasome, this compound crystals have not been found to do so despite similar morphology windows.net. Canine models, specifically dogs with naturally acquired zoonotic visceral leishmaniasis, have been used for pharmacokinetic studies of this compound and its metabolite oxypurinol longdom.orglongdom.org.

Analytical Techniques for this compound and Metabolite Quantification

Accurate quantification of this compound and its primary active metabolite, oxypurinol, in biological matrices and pharmaceutical formulations is essential for pharmacokinetic studies, bioequivalence trials, and therapeutic drug monitoring. A variety of analytical techniques have been developed and validated for this purpose.

High-Performance Liquid Chromatography (HPLC) with UV detection is a widely used method for the estimation of this compound and oxypurinol in various samples, including human serum, plasma, and urine, as well as pharmaceutical formulations longdom.orglongdom.orgijbpas.comnih.govijpsonline.comnih.govresearchgate.netijpsonline.com. This technique offers reliability and is often considered cost-effective compared to more advanced methods ijbpas.com. HPLC methods typically involve reversed-phase columns and mobile phases consisting of mixtures of buffers and organic solvents, with detection commonly performed at wavelengths around 254 nm or 242 nm longdom.orgnih.govijpsonline.com. Retention times for this compound and oxypurinol vary depending on the specific chromatographic conditions used nih.gov. For example, one HPLC-UV method reported retention times of 9.9 min for oxypurinol and 12.3 min for this compound in human serum nih.gov.

Liquid Chromatography-Mass Spectrometry (LC-MS) and Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS) offer higher sensitivity and specificity for the quantification of this compound and oxypurinol, particularly in complex biological matrices like plasma researchgate.netresearchgate.netnih.govtandfonline.comingentaconnect.com. LC-MS/MS methods often involve protein precipitation for sample preparation and utilize reversed-phase columns. Detection is typically performed using electrospray ionization in positive or negative ion mode, employing selected reaction monitoring (SRM) for enhanced selectivity researchgate.nettandfonline.comingentaconnect.com. These methods have demonstrated good linearity, accuracy, and precision over a wide range of concentrations, with lower limits of quantification often in the nanogram per milliliter range researchgate.netingentaconnect.com. For instance, a validated LC-MS/MS method for simultaneous determination of this compound and oxypurinol in human plasma reported a linear range of 0.01–10 μg/mL and a lower limit of quantification of 0.01 μg/mL for both compounds researchgate.netingentaconnect.com.

Other analytical techniques mentioned in the literature for this compound estimation include UV-Vis spectrophotometry, Ultra Performance Liquid Chromatography (UPLC), Hydrophilic-Liquid Interaction Chromatography (HILIC), spectrofluorometry, capillary electrophoresis, polarography, voltammetry, and hyphenated techniques like UPLC-MS/MS and GC-MS ijbpas.comnih.gov.

Here is a table summarizing some analytical methods for this compound and oxypurinol quantification:

Considerations for Clinical Research Design in this compound Studies

Clinical research involving this compound requires rigorous study design to evaluate its efficacy, safety, and pharmacokinetic/pharmacodynamic properties in human subjects. The design of clinical trials depends on the specific objectives, patient population, and the stage of drug development.

Randomized controlled trials (RCTs) are considered the gold standard for evaluating the efficacy of this compound in various conditions. These trials often employ double-blind, placebo-controlled designs to minimize bias bmj.comd-nb.info. For studies evaluating urate-lowering therapies (ULTs), regulatory bodies like the European Medicines Agency (EMA) provide guidelines on clinical development, including recommendations for patient selection, efficacy assessments, and trial duration raps.org. For ULTs, parallel, randomized double-blind placebo-controlled trials for at least six months are recommended raps.org. When evaluating new first-line treatments, at least one study should use this compound as an active control raps.org.

Patient selection in this compound clinical trials is crucial and often based on established diagnostic criteria for conditions like gout raps.org. Studies for ULTs commonly select patients with hyperuricemia above a certain baseline serum uric acid (sUA) level raps.org. Efficacy endpoints in ULT trials often focus on achieving and maintaining target sUA levels raps.org. The EMA recommends using sUA as a surrogate endpoint and monitoring it frequently, at least every 4 weeks raps.org. Primary endpoints for confirmatory trials for ULTs may include sustained sUA levels below a specific threshold for a defined period raps.org.

Pharmacokinetic (PK) and pharmacodynamic (PD) studies are integral to understanding how this compound is absorbed, distributed, metabolized, and excreted in humans, as well as its biochemical effects. PK/PD modeling is used to describe the relationship between this compound and oxypurinol concentrations and their effects on biomarkers like hypoxanthine, xanthine, and uric acid d-nb.infonih.gov. These studies are important for optimizing dosing regimens and evaluating potential drug interactions bmj.comcenterwatch.com. Clinical trials have investigated the PK and PD of this compound alone and in combination with other drugs, assessing parameters such as maximum serum concentration (Cmax), area under the concentration-time curve (AUC), and changes in sUA levels bmj.comnih.gov. Bioequivalence studies, often using a crossover design in healthy volunteers, are conducted to compare the PK and relative bioavailability of different this compound formulations nih.gov.

Considerations for clinical trial design also include the assessment of potential drug-drug interactions and the evaluation of this compound in specific patient populations, such as those with renal impairment or other comorbidities raps.orgfda.gov. The duration of clinical trials varies depending on the study objectives, ranging from short-term PK/PD studies to longer-term trials evaluating cardiovascular outcomes bmj.comisrctn.com.

Q. How can researchers optimize HPLC methods for quantifying this compound in dissolution studies?

• Methodological Answer : Prioritize factors with standardized effect estimates >0.4 (e.g., column rotation [1.24], HCl concentration [0.39]) during method development. Use a Plackett-Burman design to screen variables and validate precision (RSD < 2%) and accuracy (recovery 98–102%). Include a DAD detector for peak purity assessment .

Advanced Research Questions

Q. How should contradictory data on this compound’s impact on oxidative stress biomarkers be reconciled?

• Methodological Answer : Conduct sensitivity analyses to address heterogeneity (e.g., patient subgroups, assay types). For example, stratify meta-analyses by measurement techniques (e.g., colorimetric vs. fluorometric MDA assays) and adjust for confounders like renal function. Use random-effects models to account for between-study variance .

Q. What statistical approaches are recommended for longitudinal studies on this compound’s cardiovascular effects?

• Methodological Answer : Apply Cox proportional hazard models with propensity score matching to reduce indication bias (e.g., higher this compound use in comorbid patients). Adjust for covariates like age, urate levels, and concurrent medications. For arterial stiffness outcomes (e.g., pulse wave velocity), use mixed-effects models to handle repeated measures .

Q. How can researchers validate this compound’s anti-inflammatory role in prostate cancer models?

• Methodological Answer : Use PSA velocity as a surrogate endpoint in Phase II trials. Pair biomarker analysis (e.g., IL-6, TNF-α) with oxidative stress markers (MDA, SOD activity) to disentangle mechanisms. Employ Bayesian adaptive designs to optimize sample size and dosing schedules based on interim efficacy data .

Q. What strategies mitigate variability in xanthine oxidase inhibition assays across preclinical models?

• Methodological Answer : Standardize enzyme activity measurements (e.g., spectrophotometric uric acid detection at 290 nm) and control for substrate concentrations. In rodent studies, pre-treat with this compound (5 mg/kg, 24 hr pre-sacrifice) to ensure tissue XO inhibition. Report inter-lab variability using interclass correlation coefficients (ICC) .

Data Presentation Guidelines

• Tables : Include effect sizes, confidence intervals, and p-values for key outcomes (e.g., MDA reduction ).
• Figures : Label factors in HPLC optimization plots with effect magnitudes (e.g., rotation = 1.24 ).
• Reproducibility : Follow ALPL standards for data transparency, detailing raw data repositories and analysis scripts .