Development and characterization of allopurinol-loaded transethosomal gel for topical gout management.

Febuxostat alleviates gout-associated hyperuricemia and inflammation by downregulating IL1A to modulate TLR2/TLR4/NF-κB signaling pathway.

Background: d-Limonene (LIM) is a food-derived monoterpenoid phytocompound predominantly found in citrus peels, endowed with potent antioxidant and anti-inflammatory properties, and has been reported to inhibit xanthine oxidase (XO) activity in vitro. This study investigated the dose-sparing efficacy of this dietary bioactive compound in combination with low-dose allopurinol (ALP) using a dual rat model combining potassium oxonate (PO)-induced hyperuricemia and monosodium urate (MSU)-triggered gouty arthritis, thereby capturing both metabolic and inflammatory dimensions of gout. Methods: Female Wistar rats were PO-primed and MSU-challenged, then treated with LIM (50 mg/kg), ALP (5 or 10 mg/kg), or LIM + ALP. Outcomes included paw thickness, dysfunction and inflammation indices, serum uric acid, urea, creatinine, AST/ALT, cytokines (IL-1β, TNF-α, IL-6), oxidative stress markers (MDA, SOD, catalase, GSH), and NLRP3 immunoreactivity, supported by radiographic and histopathological analyses. Data were analyzed by one-way ANOVA with Tukey’s post hoc test. Results: LIM improved clinical and biochemical outcomes versus monotherapies. However, LIM + low-dose ALP exhibited the greatest overall efficacy. On Day 30, paw thickness was significantly lower with LIM + ALP than with LIM alone (3.25 ± 0.31 vs. 3.98 ± 0.72 mm; p < 0.001). Serum uric acid and hepatic transaminases declined most with the combination (p < 0.0001 vs. LIM), accompanied by improved renal indices (p < 0.001). Pro-inflammatory cytokines were markedly reduced, NLRP3 immunostaining was minimal, and oxidative balance shifted toward homeostasis (↓ MDA; ↑ SOD, catalase, GSH). Radiographic and histological evaluations corroborated attenuation of joint inflammation and tissue damage. Conclusions: In the PO + MSU gout model, co-administration of the food-derived compound LIM with low-dose ALP achieved additive, dose-sparing benefits across metabolic, inflammatory, and histological endpoints. While in vivo XO activity was not directly assessed, the findings are consistent with XO-pathway modulation, NLRP3–IL-1β suppression, and redox restoration. These results highlight the potential of dietary bioactives such as d-Limonene to complement standard urate-lowering therapy, warranting further pharmacokinetic and safety validation.

Controlled drug release properties of allopurinol-incorporated double-layered chitosan/starch patches for gout therapy.

Background: Well-known traditional Indian medication Operculina turpethum is used to treat fever, bronchitis, ulcers, haemorrhoids, tumours, obesity, and jaundice. An excessively elevated level of uric acid in the blood is known as hyperuricaemia. The widespread presence of hyperuricemia has been steadily rising globally nowadays. Clinical treatments for hyperuricemia are benzbromarone and probenecid as uricosuric agents and Allopurinol (ALP) and febuxostat as Xanthine Oxidase (XOD) inhibitors. However, only a small number of medications are available due to the poor tolerance of these therapies and their potential for adverse effects, including hepatotoxicity, kidney disorders, gastrointestinal symptoms, and hypersensitivity syndrome. Aim: Utilizing both in vivo and in vitro studies, we examined the Antihyperuricemic potential of Operculina turpethum Root Ethanol Extract (OTRE) as well as its underlying mechanisms of action. Methods: We investigated the amounts of uric acid in serum as well as the inhibition of xanthine oxidase (XOD) in the liver tissue of a hyperuricemic rat model created by potassium oxonate (PO). In this in vitro investigation OTR show strong XOD inhibitory activity when compared with ALP. Results: In comparing the IC50 values of OTRE-200 was (94.32) and ALP was (1.52). The dose of OTRE-200mg/kg and Allopurinol-Treated (ALT) 10mg/kg groups had significantly lower levels of uric acid (UA) in their urine and blood than the PC group (p &lt; 0.05) in PO-induced hyperuricemic rats. Urine UA levels were lower than serum levels in all OTE groups. In rats with PO-induced hyperuricemia, OTRE-200mg/kg reduced serum UA levels and elevated excretion of UA in the urine. Conclusion: This study showed that in rats with PO-induced hyperuricemia, OTRE increased UA excretion and decreased serum UA levels. OTRE prevents hyperuricemia by inhibiting the liver’s and serum’s XO activity in vivo and by having antioxidant activity in vitro. Major Findings: This study clarifies that OTRE shows positive benefits and could be beneficial in hyperuricemia and gout. Antihyperuricemic, Ethanolic Extract, Linn, Xanthine Oxidase

Prenylated flavanones represent a structurally diverse class of natural compounds with significant biological potential. Among them, chromene flavanones (CFs) constitute a rare and specialized subgroup with promising therapeutic applications. These molecules have gained attention due to their potential to inhibit xanthine oxidase (XO), a key enzyme involved in oxidative stress-related disorders such as gout and hyperuricemia. Their distinctive structural features, combined with notable bioactivity, make them compelling candidates for further pharmacological exploration. Given their potential relevance, this study focuses on the in vitro and in silico evaluation of three CFs isolated from Dalea boliviana Britton [Fabacea], assessing their capacity to inhibit XO and elucidating key structure-activity relationships (SARs) that contribute to their biological effectiveness. This study aims to investigate the in vitro and in silico interactions of the chromene flavanones, namely, (2S) 5,2'-dihydroxy-6″,6″-dimethylchromeno-(7,8:2″,3″)-flavanone (1), (2S) 5,2'-dihydroxy-6″,6″-dimethylchromeno-(7,8:2″,3″)-3'-prenylflavanone (2), and obovatin (3), obtained from D. boliviana, with XO, in order to explore their potential as XO inhibitors and their potential therapeutic applications for hyperuricemic diseases. XO inhibition by the three chromene flavanones was measured spectroscopically. The relationships between their structures and inhibitory activities were evaluated. Moreover, molecular docking studies were performed to propose the binding modes of the most active natural compounds. Compounds 1 and 2 exhibited potent inhibition, with IC50 values in the nanomolar range (0.5 ± 0.01nM and 1.7 ± 0.46nM, respectively), demonstrating significantly higher activity than allopurinol (AL), the reference inhibitor (IC50 = 247 ± 4nM). In contrast, compound 3 displayed only weak inhibition. SAR analysis revealed that the presence of a chromene moiety in the A-ring, combined with hydroxyl and prenyl groups in the B-ring, played a crucial role in enhancing inhibitory activity. Molecular docking studies confirmed the strong binding affinities of compounds 1 and 2 within the active site of XO (PDB ID: 3NVY), with binding energies of -6.1687kcal/mol and -6.7820kcal/mol, respectively. Key stabilizing interactions involved π-π interactions with Phe914 and hydrogen bonding with residues such as Leu873 and Leu1014. These findings highlight the structural features essential for potent XO inhibition and suggest that chromene flavanones represent a valuable scaffold for the development of novel inhibitors. Further molecular dynamics simulations could provide deeper insights into their stability and interaction dynamics, aiding in the rational design of more effective XO inhibitors. Our findings lead us to propose these chromene flavanones as lead compounds for the design and development of novel XO inhibitors for treating diseases in which exacerbated activity of this enzyme is involved.

This work focused on the development of a retentive drug delivery system (DDS) able to float in the gastric fluids and to ensure prolonged release of drugs over a pre-defined period of time, being then safely emptied from the stomach. To this end, the design step played a pivotal role. The device was thus devised to be composed of a polyvinyl alcohol-based matrix with a tapered geometry, which was partially coated with an insoluble layer of thermoplastic elastomer. This way, release of allopurinol (ALP), used as model drug, could occur only from the uncoated surfaces, while the peculiar geometry of the hydrophilic swellable/erodible matrix was intended to balance the increase in the diffusional path over time with a wider release area. In addition, the coating featured air pockets, whose volume was sized to compensate for the weight force of the DDS once immersed in gastric fluids, thus ensuring its long-lasting buoyancy. By easing the entrance of gastric fluids when the matrix is completely exhausted, such air pockets would also favor sinking and removal of the DDS from the pylorus. Given the multi-layered geometry of the final floating device, including hard-to-fabricate details (e.g. uncoated surfaces, voids), fused deposition modeling 3D printing was identified as the technique of choice for its effectiveness in manufacturing complex shapes. Various formulations were tested for fabricating both the inner matrix and the outer coating, assessing their thermo-mechanical properties, printability and release behavior. The gastro-retentive system demonstrated prolonged buoyancy (> 12h) and a wide portfolio of ALP release performances, differing in rate and duration, which would make it a promising platform for personalized delivery of drugs in the upper gastrointestinal tract.

Peptides have emerged as promising agents for ameliorating hyperuricemia (HUA), a condition that poses significant risks to human health. This study evaluated the HUA-alleviating potential of skipjack tuna dark muscle hydrolysate (STDH) in a mouse model of HUA induced by potassium oxonate (PO) and hypoxanthine (Hx). The results demonstrated elevated serum uric acid (SUA) levels, increased xanthine oxidase (XOD) activity in the serum and liver, and kidney and intestinal damage in HUA mice. Although the standard drug allopurinol (AP) effectively reduced SUA levels and lowered XOD activity in the serum and liver, it exacerbated kidney damage and caused significant weight loss. In contrast, STDH intervention not only significantly lowered SUA, serum creatinine (SCr), and blood urea nitrogen (BUN) levels but also inhibited XOD activity in serum and liver. Notably, STDH ameliorated renal and intestinal morphological damage, as evidenced by hematoxylin-eosin (HE) staining. Gut microbiome analysis further revealed that STDH normalized the HUA-associated elevation of the Bacteroidetes/Firmicutes ratio. Untargeted metabolomics identified STDH's regulatory effects on glycine, serine, and threonine metabolism; arginine and proline metabolism; and glycerophospholipid metabolism, with glutamine implicated as a key player in HUA pathogenesis. These findings demonstrate that STDH effectively alleviates HUA while avoiding adverse effects associated with conventional therapy, positioning it as a safe and cost-effective functional food candidate for HUA management.

Hyperuricemia (HUA) is characterized by metabolic abnormalities in purine metabolism, leading to an excessive accumulation of uric acid in the bloodstream. This condition is not only prevalent but also significantly linked to the exacerbation of various chronic diseases, including renal impairment. Notably, asymptomatic hyperuricemia is frequently associated with inflammatory responses and alterations in intestinal microbiota. Thus, it is imperative to explore effective therapeutic interventions for HUA to mitigate its associated health risks. The present study aimed to elucidate the protective effects of Plantaginis Semen polysaccharides (PSP) in a rat model of hyperuricemia induced by adenine (AD) and potassium oxonate (PO) gavage. Over a treatment period of five weeks, the animals received either PSP or allopurinol (AL). Comprehensive assessments were performed, including blood biochemistry analysis, histopathological evaluation, Western blot analyses to investigate the expression levels of key renal transport proteins, as well as 16S rRNA sequencing to explore microbiota shifts. The findings demonstrated that PSP significantly decreased serum uric acid (UA) levels and alleviated renal dysfunction through modulation of xanthine oxidase (XOD) and adenosine deaminase (ADA) serum concentrations and the expression of renal transporters, namely glucose transporter protein 9 (GLUT9), urate transporter 1 (URAT1), ATP-binding cassette superfamily member 2 (ABCG2), and organic anion transporter 1 (OAT1). Furthermore, PSP exhibited notable anti-inflammatory properties, reflected in the reduced levels of pro-inflammatory cytokines such as tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β). In summary, the present study substantiates the therapeutic potential of PSP in treating hyperuricemia through its dual action of lowering uric acid levels and imparting anti-inflammatory effects. The observed modulation of gut microbiota further supports the role of PSP in maintaining metabolic homeostasis. Future investigations should focus on the clinical applicability of PSP and elucidate the mechanisms underlying its beneficial impacts on hyperuricemia and associated metabolic disorders.

Nonalcoholic steatohepatitis (NASH) is a chronic liver disease which can lead to cirrhosis and hepatic failure. It is observed in patients with both type 1 and type 2 diabetes mellitus (T1DM, T2DM). Allopurinol, a xanthine oxidase inhibitor that is widely used in clinical practice, has been demonstrated to reduce hepatic oxidative stress and attenuate acute liver injury which may be through activation of antioxidant pathways. This work aimed at investigating the role of Allopurinol (ALP) in attenuation of type 1 diabetes associated with Nonalcoholic fatty liver disease (NAFLD) and exploring the possible molecular mechanism by which ALP attenuates NASH in type 1 diabetes. Forty-five adult male albino rats were included in the study. They were randomly allocated to 3 equal groups: group I (control), Group II (diabetic animals), Group III (diabetic animals with allopurinol treatment). At the end of this experimental study measurements of serum glucose, ALT, AST, cholesterol, triglyceride, serum levels of uric acid, malondialdehyde (MDA), serum superoxide dismutase (SOD) were done. Histological analysis of liver tissue to diagnose steatohepatitis and gene expression of nuclear factor-erythroid-2- related factor-2 (Nrf2) &amp; TNFα were done. Diabetic rates treated with allopurinol (group III) showed decrease in serum levels of ALT, AST, cholesterol, uric acid and MDA compared to diabetic rat group. As regards TNF, gene expression was significantly decreased in group III compared to group II. This study also demonstrated that Nrf2α was significantly increased in group III compared to group II. Allopurinol also, ameliorated the histopathological changes observed in group II. In conclusion, allopurinol treatment increases the Nrf2 gene expression in the liver of STZ-induced diabetic rats and ameliorates steatohepatitis through modulation of TNF-α gene expression. Allopurinol could be a candidate for prevention or treatment of NAFLD.

Self-assembled mixed nanomicelles based hydrogel for enhanced transdermal bioavailability of allopurinol in gout therapy: In vitro and In vivo evaluation

Density functional theory analyses of an iron-doped nanocage for the adsorption of allopurinol drug towards the development of novel carriers

Investigating the potential of graphene and nitrogen carbide nanosheets as efficient sensors for drug detection through theoretical analysis

Epigallocatechin gallate (EGCG), a prominent bioactive compound found in tea, offers numerous health benefits. Previous studies have highlighted its potential in mitigating hyperuricemia. In this study, hyperuricemic mice induced by potassium oxonate (PO) were treated with EGCG or the anti-hyperuricemia medication allopurinol (AP) to investigate the mechanisms underlying their anti-hyperuricemic effects. The results demonstrated that both EGCG and AP significantly reduced serum uric acid (UA) levels. Further analysis revealed that EGCG promoted the expression of UA secretion transporter genes (Oat1 and Oct1) while inhibiting the expression of UA reabsorption transporter genes (Urat1 and Glut9) in the kidney. By 16S rDNA sequencing, EGCG, but not AP, was found to alter the composition of the gut microbiota. Notably, EGCG induced significant changes in the relative abundance of specific bacteria such as Lactobacillus, Faecalibaculum, and Bifidobacterium, which displayed high correlations with serum UA levels and UA-related gene expression. Metabolomic analysis suggested that EGCG-induced modifications in bacterial metabolites might contribute to the alleviation of hyperuricemia. Transcriptomic analysis of the intestinal epithelium identifies 191 differentially expressed genes (DEGs) in EGCG-treated mice, including 8 purine-related genes. This study elucidates the anti-hyperuricemic mechanisms of EGCG, particularly its influence on the gut microbiota and gene expression in the intestinal epithelium.

An appropriate non-oral platform via transdermal delivery of drugs is highly recommended for the treatment of hyperuricemia. Herein, a core-shell structured microneedle patch with programmed drug release functions was designed to regulate serum uric acid (SUA) levels for prolonged hyperuricemia management. The patch was fabricated using a three-step casting method. Allopurinol (AP), an anti-hyperuricemic drug, was encapsulated within the carboxymethyl cellulose (CMC) layer, forming the "shell" of the MNs. The MN's inner core was composed of polyvinylpyrrolidone (PVP) loaded with urate oxidase-calcium peroxide nanoparticles (UOx-CaO2 NPs). When the as-fabricated core-shell structured microneedles were inserted into the skin, the loaded AP was first released immediately to effectively inhibit the production of SUA due to the water solubility of CMC. Subsequently, the internal SUA was further metabolized by UOx, leading to exposure of CaO2 NPs. The sustained release of UOx accompanied by the decomposition of CaO2 NPs contributed to maintaining a state of normal uric acid levels over an extended period. More attractively, uric acid could be oxidized due to the strong oxidant of CaO2, which was beneficial to the continuous consumption of uric acid. In vivo results showed that the as-fabricated MNs exhibited an excellent anti-hyperuricemia effect to reduce SUA levels to the normal state within 3 h and maintain the normouricemia state for 12 h. In addition, the levels of creatinine (Cr) and blood urea nitrogen (BUN) in the serum remained within the normal range, and the activities of adenosine deaminase (ADA) and xanthine oxidase (XOD) in the liver were effectively inhabited, mitigating the risk of liver and kidney damage for clinical anti-hyperuricemia management.

Allopurinol (ALO) is a medication that treats gout andkidney stonesby lowering uric acid synthesis in the blood. The biopharmaceuticsclassification system (BCS) IV drug exhibits poor aqueous solubility,permeability, and bioavailability. To overcome the bottlenecks ofALO, salts with maleic acid (MLE) and oxalic acid (OXA) were synthesizedusing the solvent-assisted grinding method. The novel multicomponentsolids were characterized by PXRD, DSC, TGA, FT-IR, and SEM images.The crystal structures of these salts with variable stoichiometrywere obtained using Rietveld refinement from the high-resolution PXRDdata. The proton from the dicarboxylic acid is transferred to themost basic pyrimidine “N” of ALO. The N–H···Nhydrogen-bonded ALO homodimer is replaced by the N+–H···O– ionic interactions in ALO–OXA (2:1:0.4) andALO–MLE (1:1:1) salt hydrates. The organic salts improved solubilityand dissolution up to 5-fold and the diffusion permeability up to12 times compared to the native drug in a luminal pH 6.8 phosphatebuffer medium. The salt hydrates were exceptionally stable duringstorage at 30 ± 5 °C and 75 ± 5% relative humidity.Superior dissolution and diffusion permeability of the ALO–MLEsalt resulted in improved pharmacokinetics (peak plasma concentration)that offers a promising solid dosage form with enhanced bioavailabilityand lower dosage formulation.

Reno- and hepato-protective effect of allopurinol after renal ischemia/reperfusion injury: Crosstalk between xanthine oxidase and peroxisome proliferator-activated receptor gamma signaling.

Allopurinol (ALP) is a successful drug used in the treatment of gout. However, this drug has been implicated in hypersensitivity reactions that can cause severe to life-threatening reactions such as Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN). Individuals who carry the human leukocyte antigen (HLA)-B*58:01 allotype are at higher risk of experiencing a hypersensitivity reaction (odds ratios ranging from 5.62 to 580.3 for mild to severe reactions, respectively). In addition to the parent drug, the metabolite oxypurinol (OXP) is implicated in triggering T cell-mediated immunopathology via a labile interaction with HLA-B*58:01. To date, there has been limited information regarding the T-cell receptor (TCR) repertoire usage of reactive T cells in patients with ALP-induced SJS or TEN and, in particular, there are no reports examining paired αβTCRs. Here, using in vitro drug-treated PBMCs isolated from both resolved ALP-induced SJS/TEN cases and drug-naïve healthy donors, we show that OXP is the driver of CD8+ T cell-mediated responses and that drug-exposed memory T cells can exhibit a proinflammatory immunophenotype similar to T cells described during active disease. Furthermore, this response supported the pharmacological interaction with immune receptors (p-i) concept by showcasing (i) the labile metabolite interaction with peptide/HLA complexes, (ii) immunogenic complex formation at the cell surface, and (iii) lack of requirement for antigen processing to elicit drug-induced T cell responsiveness. Examination of paired OXP-induced αβTCR repertoires highlighted an oligoclonal and private clonotypic profile in both resolved ALP-induced SJS/TEN cases and drug-naïve healthy donors.

Abstract Background and Aims Uric acid is relatively low in hemodialysis because it is removed during dialysis. The therapeutic intervention for hyperuricemia is controversial. RCT of allopurinol and febuxostat has been performed in hyperuricemic patients to inhibit xanthine oxido reductase (XOR) and reduce uric acid levels further improve outcomes. Nonetheless, we reported preventive effect of XOR inhibitors for dialysis patients on Sci Rep 2017, but the difference in the protective effect for CVD events and mortality between XOR inhibitors is insufficient in dialysis patients. Furthermore, febuxostat is also known to be a potent ATP-binding cassette transporter subfamily G member 2 (ABCG2) inhibitor that promotes the accumulation of uremic toxins by excretion from the gut in dialysis patients and hyperuricemic patients. We investigated the preventative effect of XOR inhibitors on outcomes under three year observation for 6575 hemodialysis patients. Method 6575 dialysis patients were divided into baseline 3 groups (ALLO group, FEB group, non-treatment group). Outcomes were all-cause mortality and CVD events, defined by ICD coding using longitudinal data. Causal associations for outcomes of allopurinol (ALLO) or febuxostat (FEB) were analized using 3 years of longitudinal data versus control at each visit, including concomitant drugs, marginal structural models (MSM) that examined the causal effect of ALLO or FEB versus control with weight for adjust covariate using multiple imputation for missing data. Results Over all all-cause death was 1167 / 6575 (17.74%) cases. In non-treated group 993 / 4827(20.57%), ALLO-treated group 98 / 778 (12.60%), and 136 / 970 (14.20%) in FEB-treated group. CVD events 14723,and number of cvd events for each treatment group non-treated 11229 events, ALLO 1377, FEB 2117 events. MSM indicated that ALLO estimated HR 0.35 for all cause mortality versus non-treated group (p&amp;lt;0.001). MSM also indicated that FEB estimated HR 0.42 for all cause mortality versus un treatment (p&amp;lt;0.001). There was no difference of preventive effect between ALLO and FEB for all cause mortality, but each drugs indicated preventive effect in each base line XOR treatment categories. In CVD events, ALLO indicated preventive effect of HR 0.81 versus control (p&amp;lt;0.001). But FEB did not indicated preventive effect of HR 0.98 (95% CI: 0.91 -1.04). ALLO was estimated preventive effect for CVD events against FEB in HR 0.83 (95% CI 0.75-0.92). Conclusion ALLO and FEB had a prevent effect for all-cause mortality, further FEB was not inferior to ALLO in all-cause mortality in the realm of XOR inhibition. Nevertheless, FEB could not indicate preventive effect for CVD events compared with ALLO and control, which is assumed of ABCG2 inhibitory effect. But was not increase risk for all cause mortality or CVD events compared with ALLO and control. This study provide a new suggestion that it is important for CKD patients to apply extrarenal excretion pathway ABCG2 of uremic toxin and uric acid to prevent CV events because of impaired renal function. In humans 70% of uremic toxin is excreted from urine, and 30% from gut. It is required further investigation and treatment strategies of uric acid lowering therapy should be considered about excretion of uremic substances outside of the kidneys.

Objectives: Methotrexate (MTX) is commonly used in the management of several malignancies and autoimmune disorders; however, testicular damage is one of the most detrimental effects of MTX administration. The current the protective effect of xanthine oxidase inhibitors either purine analogue; allopurinol (ALL) or non-purine analogue; febuxostat (FEB) in testicular injury induced by MTX in rats. Materials and methods: Thirty-two rats were randomly allocated to four groups; control (received vehicles), MTX (received single dose, 20 mg/kg, i.p.), MTX + ALL (received MTX plus ALL) and MTX + FEB (received MTX plus ALL). ALL and FEB were administered orally at 100- and 10 mg/kg, respectively for 15 days. Total and free testosterone were measured in serum. In addition, total antioxidant capacity (TAC), epidermal growth factor (EGF), malondialdehyde (MDA), tumor necrosis factor-α (TNF-α), extracellular signal-regulating kinase1/2 (ERK1/2), and total nitrite/nitrate (NOx) end products were measured in testicular tissues. At the same time, immunoexpression of HO-1in testicular tissue was measured. Histopathological examination was done. Results: ALL and FEB increased total and free serum testosterone. Both drugs showed a significant reduction in testicular MDA, NOx, TNF-α levels with an increase in TAC, EGF, and ERK1/2 levels in testicular tissue. Furthermore, both drugs enhanced HO-1 immunoexpression in testicular tissue. All these findings were parallel to the preservation of normal testicular architecture in rats treated with ALL and FEB. Conclusion: All and FEB were equally protective against testicular damage induced by MTX through anti-inflammatory, anti-apoptotic, and antioxidant actions. Their effects might be through activation of the EGF/ERK1/2/HO-1 pathway.