Controversies and practical management of patients with gout and chronic kidney disease.

Uric acid is a toxin retained with advancing kidney disease. Clinical manifestations of hyperuricemia include gout and systemic inflammation that are associated with increased risk for cardiovascular mortality. As many as one third of all patients with chronic kidney disease (CKD) have a history of gout, yet <25% of these patients are effectively treated to target serum urate levels of ≤6 mg/dL. A major reason for ineffective management of gout and hyperuricemia is the complexity in managing these patients, with some medications contraindicated, others requiring special dosing, potential drug interactions, and other factors. Consequently, many nephrologists do not primarily manage gout despite it being a common complication of CKD, leaving management to the primary physician or rheumatologist. We believe that kidney specialists should consider gout as a major complication of CKD and actively manage it in their patients. Here, we present insights from nephrologists and rheumatologists on a team approach to gout management that includes the nephrologist.

Efficacy and Safety of Allopurinol and Febuxostat in Patients With Gout and CKD: Subgroup Analysis of the STOP Gout Trial.

RATIONALE & OBJECTIVE: We conducted a prespecified examination of the efficacy and safety of allopurinol and febuxostat administered using a treat-to-target strategy in trial participants with chronic kidney disease (CKD). STUDY DESIGN: Prespecified sub cohort analysis of a randomized controlled trial. SETTING: & Participants: A sub study of the STOP Gout trial in participants with CKD. CKD was defined as an eGFR 30-59 mL/min/1.73 m2 at baseline. EXPOSURE: Trial participants with CKD and gout and serum urate (sUA) concentration ≥6.8 mg/dL were randomized 1:1 to receive allopurinol or febuxostat. Urate lowering therapy (ULT) was titrated during weeks 0-24 to achieve a goal sUA of <6.0 mg/dl (<5.0 mg/dl with tophi) (Phase 1) and maintained during weeks 25-48 (Phase 2). Gout flare was assessed between weeks 49-72 (Phase 3). OUTCOME: Gout flare between weeks 49-72 (Phase 3) was the primary outcome. Secondary outcomes included sUA goal achievement and ULT dosing at end of Phase 2, and serious adverse events (SAEs). ANALYTICAL APPROACH: Outcomes between treatment groups were compared using logistic regression models for binary outcomes, and Poisson regression for flare rates. Multivariable models were subsequently used, adjusting for factors identified to be imbalanced by treatment arm. RESULTS: 351 of 940 participants (37.3%) had CKD; 277 were assessed for the primary outcome. Fewer patients randomized to allopurinol had a flare during phase 3 (32% vs 45%; p=0.02) despite similar attainment of sUA goal (79% vs. 81%; p=0.6) by the end of Phase 2. Acute kidney injury (AKI) was more common in participants with stage 3 CKD randomized to allopurinol compared to febuxostat. LIMITATIONS: Limited power to assess infrequent safety events, largely male, older population. CONCLUSIONS: Allopurinol and febuxostat are similarly efficacious and well-tolerated in the treatment of gout in people with CKD when used in a treat-to-target regimen.

Estimation of adherence to urate-lowering therapy in people living with gout using Australia's Pharmaceutical Benefits Scheme and patient-reported dosing.

AIMS: The aim of this study was to estimate adherence to urate-lowering therapy (ULT), predominately allopurinol, from Australia's Pharmaceutical Benefits Scheme (PBS) claims database in association with (1) patient-reported doses and (2) World Health Organization's (WHO) defined daily doses (DDD), namely, allopurinol (400 mg/day) or febuxostat (80 mg/day). METHODS: Proportion of days covered (PDC) was calculated in 108 Gout App (Gout APP) trial participants with at least two recorded ULT dispensings in an approximately 12-month period before provision of intervention or control apps. Adherence was defined as PDC ≥80%. We measured the correlation between the two methods of calculating PDC using a Wilcoxon signed rank test. Agreement between ULT-taking status (self-reports) and ULT-dispensed status (PBS records) was tested with Cohen's kappa (κ), and positive and negative percent agreement. RESULTS: Allopurinol was prescribed in 93.5% of participants taking ULT. Their self-reported mean daily dose (SD) was 291 (167) mg/day. Mean PDC (SD) for allopurinol was 83% (21%) calculated using self-reported dose, and 63% (24%) using WHO's DDD. Sixty-three percent of allopurinol users were identified as adherent (PDC ≥80%) using self-reported dose. There was good agreement between self-reported ULT use and PBS dispensing claims (κ = 0.708, P < .001; positive percent agreement = 90%, negative percent agreement = 82%). CONCLUSIONS: Participant-reported allopurinol daily doses, in addition to PBS dispensing claims, may enhance confidence in estimating PDC and adherence compared to using DDD. This approach improves adherence estimations from pharmaceutical claims datasets for medications where daily doses vary between individuals or where there is a wide therapeutic dose range.

The contradictory role of febuxostat in ABCG2 expression and potentiating hypericin-mediated photodynamic therapy in colorectal cancers.

Photodynamic Therapy (PDT) is an emerging method to treat colorectal cancers (CRC). Hypericin (HYP) is an effective mediator of PDT and the ABCG2 inhibitor, Febuxostat (FBX) could augment PDT. HT29 and HEK293 cells showed light dependant cytotoxic response to PDT in both 2D and 3D cell models. FBX co-treatment was not found to improve PDT cytotoxicity. Next, ABCG2 protein expression was observed in HT29 but not in HEK293 cells. However, ABCG2 gene expression analysis did not support protein expression results as ABCG2 gene expression results were found to be higher in HEK293 cells. Although HYP treatment was found to significantly reduce ABCG2 gene expression levels in both cell lines, FBX treatment partially restored ABCG2 gene expression. Our findings indicate that FBX co-treatment may not be suitable for augmenting HYP-mediated PDT in CRC but could potentially be useful for other applications.

Comparative studies of xanthine oxidase inhibitors viz. allopurinol and febuxostat against induced hyperuricaemia in a poultry model.

In this study, an attempt was made to evaluate the relative efficacy of two important anti-gout agents, viz. allopurinol and febuxostat, in the control of hyperuricaemia/gout using a poultry model. A 21-day study was conducted on 48 Vencobb-400 broiler chicks randomly divided into four groups. In one group hyperuricaemia/gout was induced by the oral administration of diclofenac (group D); in two other groups the ameliorative effect of the two drugs under study was investigated by providing both simultaneously, i.e. diclofenac and allopurinol (group DA), diclofenac and febuxostat (group DF); and the fourth group was kept un-induced and untreated as a control (group C). Both allopurinol and febuxostat inhibit xanthine oxidase enzymes, thereby reducing the production of uric acid. The birds kept on diclofenac alone exhibited the highest level of hyperuricaemia, clinical signs of gout, and overt adverse changes in the visceral organs, whereas these changes were lesser in allopurinol- and febuxostat-treated groups. Furthermore, haematological, biochemical, patho-morphological, and ultra-structural studies using transmission electron microscopy were carried out to evaluate the pathology and, thus, the ameliorative effect of allopurinol and febuxostat. The findings proved that allopurinol and febuxostat carry definite ameliorative potential as anti-hyperuricemic and anti-gout agents in poultry, which was better expressed by febuxostat compared to allopurinol.

Two cases report of febuxostat-induced acute liver injury: acute heart failure as a probable risk factor?

Drug induced liver injury, as a sub-type of hepatotoxicity, is rare but practical problem, producing challenges for clinicians. Within the recent two months, two patients with heart failure develop febuxostat-induced acute liver injury during hospital stay. To the best of our knowledge, very few cases of febuxostat-induced hepatotoxicity have been reported up to now. In this paper, two unusual cases of febuxostat-induced acute liver injury are herein described. The medical history, drug treatment, clinical symptoms, liver function tests, diagnosis and prognosis are fully given in this paper. It should be noticed that, two liver injury happen in patients of heart failure with reduced ejection fraction. Whether heart failure is a risk factor of febuxostat related liver injury, deserves further research. This paper reminds the clinicians that more attention should be paid to the acute liver injury caused by febuxostat, and liver function tests are suggested especially for patients of heart failure.

Reno-protective effect of fenofibrate and febuxostat against vancomycin-induced acute renal injury in rats: Targeting PPARγ/NF-κB/COX-II and AMPK/Nrf2/HO-1 signaling pathways.

BACKGROUND: Vancomycin (VCM) is used clinically to treat serious infections caused by multi-resistant Gram-positive bacteria, although its use is severely constrained by nephrotoxicity. This study investigated the possible nephroprotective effect of febuxostat (FX) and/or fenofibrate (FENO) and their possible underlying mechanisms against VCM-induced nephrotoxicity in a rat model. METHODS: Male Wistar rats were randomly allocated into five groups; Control, VCM, FX, FENO, and combination groups. Nephrotoxicity was evaluated histopathologically and biochemically. The oxidative stress biomarkers (SOD, MDA, GSH, total nitrite, GPx, MPO), the apoptotic marker, renal Bcl-2 associated X protein (Bax), and inflammatory and kidney injury markers (IL-1ß, IL-6, TNF-α, Nrf2, OH-1, kappa-light-chain-enhancer of activated B cells (NF-κB), NADPH oxidase, Kim-1, COX-II, NGAL, Cys-C were also evaluated. RESULTS: VCM resulted in significant elevation in markers of kidney damage, oxidative stress, apoptosis, and inflammatory markers. Co-administration of VCM with either/or FX and FENO significantly mitigated nephrotoxicity and associated oxidative stress, inflammatory and apoptotic markers. In comparison to either treatment alone, a more notable improvement was observed with the FX and FENO combination regimen. CONCLUSION: Our findings show that FX, FENO, and their combination regimen have a nephroprotective impact on VCM-induced kidney injury by suppressing oxidative stress, apoptosis, and the inflammatory response. Renal recovery from VCM-induced injury was accomplished by activation of Nrf2/HO-1 signaling and inhibition of NF-κB expression. This study highlights the importance of FX and FENO as effective therapies for reducing nephrotoxicity in VCM-treated patients.

Association between the initial dose urate-lowering drugs and gout flares in adult males with gout.

OBJECTIVES: Frequent gout attacks in the initial introduction of urate-lowering therapy (ULT) are significant causes of poor drug adherence and ULT discontinuation. Initial low-dose urate-lowering drugs may be effective in reducing gout flares, however, robust evidence is sparse. The aim of this study was therefore to assess the association of initial dose urate-lowering drugs with gout flares in adult males with gout during the initial introduction of ULT. METHODS: This cohort study obtained data on consecutive gout patients from a single-center gout cohort study from August 2017 to October 2020. A standard questionnaire was applied to collect demographic and clinical information, and biochemical parameters were tested on the same day. The primary end point was to estimate the association of initial dose febuxostat with gout flares, using cox hazard models with inverse probability of treatment weighting (IPTW). RESULTS: A total of 582 gout patients were included in this study. During 6-week follow-up, 71 (12.2%) patients suffered gout flares. In the main analysis using cox hazard models with IPTW, compared with colchicine prophylaxis, initial low-dose febuxostat alone had no statistical significance with the increased risk of gout flares [hazard ratio (HR), 1.26; 95% CI, 0.58-2.72], while initial high-dose febuxostat was associated with an increased risk of gout flares (HR, 3.08; 95% CI, 1.34-7.07). CONCLUSIONS: This observational study demonstrated that initial low-dose febuxostat was equally effective in preventing gout flares as colchicine prophylaxis, while initial high-dose febuxostat alone was associated with an increased risk of gout flares.

Comparison between the Effects of Allopurinol and Febuxostat on the Survival of Patients on Maintenance Hemodialysis.

INTRODUCTION: There were insufficient pieces of evidence regarding the effect of the two drugs (allopurinol and febuxostat) on patient survival in hemodialysis (HD) patients. Herein, we aimed to compare the efficacy of uric acid-lowering drugs (ULDs) or the type of the drug on patient survival using a representative sample of maintenance HD patients in South Korea. METHODS: This study used data from a national HD quality assessment program and the claims data. Use of ULDs was defined as more than one prescription during the 6 months of each HD quality assessment period. The patients were divided into three groups. Patients who were not prescribed allopurinol or febuxostat were included in group 1 (n = 43,251); patients who were prescribed allopurinol were included in group 2 (n = 9,987); and patients who were prescribed febuxostat were included in group 3 (n = 2,890). RESULTS: Kaplan-Meier curves showed that the survival rate was greatest in group 3 and worst in group 1 among the three groups. Multivariable analysis showed that group 2 had better patient survival compared to group 1; however, there was no significant difference in patient survival between groups 2 and 3. In addition, patients with hyperuricemia or gout had better patient survival compared to those without these diseases. CONCLUSIONS: Our study showed that survival in patients receiving ULDs was not inferior to that of those not receiving ULDs. Patient survival between patients on HD receiving allopurinol and those receiving febuxostat was similar.

Association between use of febuxostat and muscle injury: A disproportionality analysis and meta-analysis of randomized controlled trials.

AIMS: Several reports have suggested an association between febuxostat and muscle injury. The purpose of this study was to determine whether febuxostat increases the risk of muscle injury. This study included an analysis of the US Food and Drug Administration Adverse Event Reporting System (FAERS) database and a systematic review/meta-analysis of randomized controlled trials. METHODS: First, evaluation of the FAERS data included a disproportionality analysis that compared patients with and without rhabdomyolysis according to whether they were receiving febuxostat or allopurinol. Second, a systematic review/meta-analysis was performed to assess the risk of rhabdomyolysis and muscle injury in patients who used febuxostat or allopurinol. RESULTS: Analysis of the FAERS data revealed disproportionality for increasing rhabdomyolysis in patients who received febuxostat (reporting odds ratio 4.49, 95% confidence interval [CI] 3.72-5.38, P < .01) and allopurinol (reporting odds ratio 2.49, 95% CI 2.25-2.75, P < .01). Nineteen studies were eligible for inclusion in the systematic review/meta-analysis. Rhabdomyolysis was reported in only 1 study. The risk of any type of muscle damage was not significantly increased with febuxostat compared with placebo (risk ratio 0.92, 95% CI 0.73-1.17, P = .52, I2  = 0%; 8 studies including 2597 participants, high-certainty evidence) or allopurinol (risk ratio 1.03, 95% CI 0.94-1.11, P = .56, I2  = 0%; 9 studies including 17 644 participants, moderate-certainty evidence). CONCLUSION: Febuxostat does not seem to affect the risk of muscle injury. However, the findings of this meta-analysis indicate a need for further high-quality observational studies with long-term follow-up.

C-reactive Protein Levels and Cardiovascular Outcomes After Febuxostat Treatment in Patients with Asymptomatic Hyperuricemia: Post-hoc Analysis of a Randomized Controlled Study.

PURPOSE: Inflammation plays an important role in the initiation and progression of atherosclerosis, leading to poor clinical outcomes. Hyperuricemia is associated with the activation of the Nod-like receptor protein 3 inflammasome. Here, we investigated whether inhibition of inflammation using febuxostat lowered the risk of cardiovascular events. METHODS: This is a post-hoc analysis of the randomized trial, Febuxostat for Cerebral and CaRdiorenovascular Events PrEvEntion StuDy (FREED). In total, 1067 patients (736 men and 331 women) were included in the analysis. We compared the serial changes in high-sensitivity C-reactive protein (hs-CRP) levels between febuxostat and non-febuxostat groups and assessed the correlation between the changes in uric acid (UA) and hs-CRP levels after febuxostat treatment. We also determined whether febuxostat could reduce a hard endpoint, defined as a composite of cardiovascular events and all-cause mortality. RESULTS: Serum UA levels in the febuxostat group were significantly lower than those in the non-febuxostat group after randomization (p < 0.05). However, hs-CRP levels were comparable between the two groups during the study. No significant correlation was observed between the changes in UA and hs-CRP levels after febuxostat treatment. The hard endpoints did not differ significantly between the two groups. In patients with baseline hs-CRP levels > 0.2 mg/dL or those administered 40 mg of febuxostat, the drug did not reduce hs-CRP levels or decrease the hard endpoint. CONCLUSION: Febuxostat reduced the UA levels but did not affect the CRP levels, and therefore may fail to improve cardiovascular outcomes after treatment. TRIAL REGISTRATION: ClinicalTrial.gov (NCT01984749). https://clinicaltrials.gov/ct2/show/NCT01984749.

A New Avenue for Enhanced Treatment of Hyperuricemia and Oxidative Stress: Design, Synthesis and Biological Evaluation of Some Novel Mutual Prodrugs Involving Febuxostat Conjugated with Different Antioxidants.

Febuxostat (FEB) is the first non-purine xanthine oxidase inhibitor (XOI) used for the treatment of hyperuricemia and gout. The oxidative stress induced by reactive oxygen species (ROS) which accompany purine metabolism by XO, could contribute to cellular damage and several pathological conditions. In this view, the present work addresses the evaluation of combining the hypouricemic effect of FEB and the free radical scavenging potential of various natural antioxidants in a single chemical entity by implementing the "mutual prodrug" strategy. Accordingly, a series of five ester prodrugs containing FEB together with different naturally occurring antioxidants namely, thioctic acid (4), thymol (5), menthol (6), vanillin (7), and guaiacol (8) was synthesized. Prominently, all the chemically conjugated prodrugs (4 - 8) revealed an obvious increase in the hypouricemic and antioxidant potentials when compared with their corresponding promoieties and physical mixtures. Moreover, they showed a potential protective effect against CCl4-induced hepatotoxicity and oxidative stress, together with no cytotoxicity on normal breast cells (MCF10A). Furthermore, the in vitro chemical and enzymatic stability studies of the prodrugs (4 - 8) using a developed HPLC method, verified their stability in different pHs, and rapid hydrolysis in rabbit plasma and liver homogenate to their parent metabolites. Moreover, the prodrugs (4 - 8) showed higher lipophilicity and lower aqueous solubility when compared to the parent drugs. Finally, the obtained merits from the implementation of the mutual prodrug strategy would encourage further application in the development of promising candidates with high therapeutic efficacy and improved safety profiles.

Towards the Development of Dual Hypouricemic and Anti-inflammatory Candidates: Design, Synthesis, Stability Studies and Biological Evaluation of Some Mutual Ester Prodrugs of Febuxostat-NSAIDs.

Treatment of gout involves two basic approaches: reducing the serum uric acid mainly by xanthine oxidase inhibitors (XOIs) and alleviating the intensity of the accompanying acute arthritic inflammation using non-steroidal anti-inflammatory drugs (NSAIDs). Febuxostat (FEB) is the first non-purine XOI approved for the treatment of hyperuricemia and gout. The present study aims at combining the hypouricemic effect of FEB and the anti-inflammatory (AI) properties of NSAIDs in a single entity by adopting the "mutual prodrug" approach. Accordingly, a series of seven ester prodrugs comprising basically FEB together with different NSAIDs namely, diclofenac (4), ibuprofen (5), ketoprofen (6), indomethacin (7), naproxen (8), ketorolac (9) and etodolac (10) was synthesized. All the investigated seven prodrugs (4-10) were equipotent or even superior to their corresponding parent drugs in the hypouricemic and AI activities, together with a gastrointestinal (GI) safety profile. Among this series, the prodrug FEB-DIC (4) showed excellent dual in vivo hypouricemic and anti-inflammatory activity (43.60 % and 15.96 %, respectively) when compared to the parent drugs FEB and diclofenac (36.82 % and 12.10 %, respectively) and its physical mixture (37.28 % and 12.41 %, respectively). Investigation of the in vitro chemical stability and hydrolysis of the prodrug (4) in aqueous and biological samples using a developed HPLC method confirmed its stability in various pHs, whereas rapid hydrolysis to the parent drugs in liver homogenate and human plasma was proven. Finally, it is concluded that the mutual prodrug approach could be successfully used in drug design and development for overcoming undesirable difficulties without losing the desired activities of the parent drugs.

`Risk of cardiovascular disease associated with febuxostat versus allopurinol use in patients with gout: a retrospective cohort study in Korea.

Febuxostat is the drug used to treat hyperuricemia in patients with gout. Recently, the usage of Febuxostat has been controversial over the side effects in cardiovascular. The study aimed to comparatively analyze the risk of cardiovascular disease associated with febuxostat and allopurinol use in Korean patients with gout. A cohort study was conducted using national insurance claim data from the Health Insurance Review and Assessment Service (HIRA). Adult patients who were diagnosed with gout and prescribed febuxostat or allopurinol more than once from July 1, 2015, to June 30, 2018 were studied. The outcome was cardiovascular disease. Analysis was performed using Cox's proportional hazard model following 1:1 propensity score matching to estimate the hazard ratio with a 95% confidence interval. In total, 90,590 patients were defined as the final study cohort who had an average follow-up of 467 days, including 28,732 and 61,858 patients in the febuxostat and allopurinol groups, respectively. After the 1:1 propensity score matching, the risk of cardiovascular disease in the febuxostat group was significantly higher than in the allopurinol group (HR: 1.17; 95% CI: 1.10-1.24). In the sensitivity analysis, the risk of cardiovascular disease in the febuxostat group was significantly higher than in the allopurinol group (HR: 1.09; 95% CI: 1.04-1.15). However, further sensitivity analysis showed no statistically significant difference between the febuxostat group and allopurinol group after adjusting for cardiovascular disease history before the index date. Similarly, no statistically significant difference was found between the two drugs in the subgroup analysis. Febuxostat was not associated with a significantly increased risk of cardiovascular disease.

Renoprotective effect of febuxostat on contrast-induced acute kidney injury in chronic kidney disease patients stage 3: randomized controlled trial.

INTRODUCTION: Contrast-induced acute kidney injury (CI-AKI) is known to be a complication of using intravascular contrast injection. Unfortunately, it is associated with adverse outcomes such as prolonged length of hospitalization and increased burden of health care costs. So, we aimed to determine the efficacy of febuxostat in the prevention of contrast-induced acute kidney injury among patients with chronic kidney disease Stage 3 performing percutaneous coronary intervention (PCI). METHODS: In a randomized controlled trial we enrolled 120 CKD stage 3 Patients with acute coronary syndrome referred to the cardiology department Ain-Shams University hospital for performing PCI and stenting. Patients were randomly assigned to two arms: Group I (study group): Included 60 patients who received Febuxostat added to the traditional treatment (IV hydration and N-acetylcysteine). The patients received Feburic 80 mg within 6-18 h before and within 6-18 h after the coronary intervention (a time gap of 24 h between two doses). Group II (control group): included 60 patients who received only traditional treatment. RESULTS: The incidence of AKI was higher in the control group with a statistically significant difference. We found that Independent Significant risk factors that led to AKI were febuxostate avoidance, DM, high urea level, high creatinine level, CKD stage 3B, high Mehran score and high AKI risk. CONCLUSION: We demonstrated that febuxostat has a Reno protective effect and it can help to reduce the incidence CI-AKI in CKD patients stage 3 performing PCI.

Antioxidant action of xanthine oxidase inhibitor febuxostat protects the liver and blood vasculature in SHRSP5/Dmcr rats.

BACKGROUND: Xanthine oxidase (XO) generates reactive oxygen species during uric acid production. Therefore, XO inhibitors, which suppress oxidative stress, may effectively treat non-alcoholic steatohepatitis (NASH) and atherosclerosis via uric acid reduction. In this study, we examined the antioxidant effect of the XO inhibitor febuxostat on NASH and atherosclerosis in stroke-prone spontaneously hypertensive 5 (SHRSP5/Dmcr) rats. METHODS: SHRSP5/Dmcr rats were divided into three groups: SHRSP5/Dmcr + high-fat and high-cholesterol (HFC) diet [control group, n = 5], SHRSP5/Dmcr + HFC diet + 10% fructose (40 ml/day) [fructose group, n = 5], and SHRSP5/Dmcr + HFC diet + 10% fructose (40 ml/day) + febuxostat (1.0 mg/kg/day) [febuxostat group, n = 5]. Glucose and insulin resistance, blood biochemistry, histopathological staining, endothelial function, and oxidative stress markers were evaluated. RESULTS: Febuxostat reduced the plasma uric acid levels. Oxidative stress-related genes were downregulated, whereas antioxidant factor-related genes were upregulated in the febuxostat group compared with those in the fructose group. Febuxostat also ameliorated inflammation, fibrosis, and lipid accumulation in the liver. Mesenteric lipid deposition decreased in the arteries, and aortic endothelial function improved in the febuxostat group. CONCLUSIONS: Overall, the XO inhibitor febuxostat exerted protective effects against NASH and atherosclerosis in SHRSP5/Dmcr rats.

Development and evaluation of febuxostat solid dispersion through screening method.

Febuxostat (Febux) is a BCS II drug and has a very low solubility. In order to overcome this shortcoming, the purpose of study is to increase the in vitro dissolution (%) and drug release (%) of Febux by using a screening method. The Febux-SD formulation was prepared by screening solubilizers, pH agents, and carriers using with a solvent evaporation method. The novel Febux SD formulation was successfully developed. The dissolution (%) of Febux of optimal formulation (SD3) was higher than that of Feburic® tab in pH 1.2, distilled water (DW), and pH 6.8 buffer by 6.3-, 2.6-, and 1.1-fold, respectively, at 60 min. The in vitro drug release (%) and permeability (µg/cm2) of SD3 formulation were improved compared to those of Feburic® tab in the pH shifting method and PBS (7.4), respectively. The SD3 formulation was well maintained the stability for 6 months, and that of physicochemical properties were altered. In conclusion, the Febux solubilization study with meglumine was first attempted and successfully performed. Through the improved dissolution (%) of Febux, high bioavailability of SD3 formulation is expected in animal and human studies.

Improved oral bioavailability of febuxostat by liquid self-micro emulsifying drug delivery system in capsule shells.

PURPOSE: Febuxostat is a non-purine xanthine oxidase inhibitor which belongs to the BCS class II. Main aim of this study is to enhance dissolution and bioavailability of a drug by formulating a liquid self-micro emulsifying drug delivery system (SMEDDS) in different capsule shells. METHOD: Compatability of gelatin and cellulose capsule shells was checked with different oils, surfactants and co-surfactants. Solubility studies were then carried out in selected excipients. Capryol 90, labrasol, and PEG 400 were used in a liquid SMEDDS formulation based on phase diagram and the drug loading. Further SMEDDS was characterized for zeta potential, globule size and shape, thermal stability and in vitro release. Based on the in vitro release, pharmacokinetic study was carried out using SMEDDS in gelatin capsule shells. RESULT: The diluted SMEDDS had globule size of 157.9±1.5d.nm, zeta potential of -16.2±0.4mV and they were thermodynamically stable. The formulation was found stable for 12 months in capsule shells. When tested in different media (0.1N HCl and pH 4.5 acetate buffer), the in vitro release of newly produced formulations differed substantially from that of commercially available tablets, while the release rate in alkaline medium (pH 6.8) was comparable and the highest. According to in vivo findings in rats, a threefold increase in plasma concentration, a fourfold increase in AUC0-t, and a reduction in oral clearance increased fuxostat's oral bioavailability. CONCLUSION: This investigation revealed that the novel liquid SMEDDS formulation sealed in capsules has considerable potential as a vehicle for enhancing the bioavailability of febuxostat.

[Hyperuricemia and kidney damage in patients with cardiovascular disease: A review].

Many studies have been conducted confirming the effect of uric acid (UA) on kidney function. It is obvious that there is a relationship between the effect of UA not only on kidney function, but also on the cardiovascular system, increasing cardiovascular risk. The review article provides basic information about the pathogenesis, principles and features of prescribing therapy to patients with chronic kidney disease (CKD) and cardiovascular disease. A lot of data currently indicates that hyperuricemia, both with and without crystal deposition, is associated with high cardiovascular risk and decreased kidney function. A number of studies and meta-analyses indicate that urate-reducing therapy prevents and slows down the decline in kidney function in patients with CKD, many of whom suffer from cardiovascular diseases or at least have several risk factors. Despite the fact that currently the guidelines for the treatment of CKD do not include a recommendation for the start of urate-lowering therapy, a large amount of data has been accumulated on the potential benefits of such treatment even in the absence of a diagnosis of gout. The preferred group of drugs for this group of patients are xanthine oxidase inhibitors, and for patients with eGFR below 30 ml/min/1.73 m2, it seems that allopurinol currently has larger evidence base for the efficacy and safety of prescribing.

[Prevention of urolithiasis using febuxostat in patients with metabolic syndrome].

INTRODUCTION: Urolithiasis is a chronic highly recurrent disease. The development of new methods of its pathogenetic treatment and prevention is a priority task of practical urology. AIM: To evaluate the clinical efficiency and safety of Febuxostat-SZ and to develop the rec-ommendations for its use in patients with uric acid stones. MATERIALS AND METHODS: The analysis of 525 patients with urolithiasis was carried out. On the basis of a comprehensive examination, they were divided into two groups: in the group 1, pa-tients (n=231) had urolithiasis and metabolic syndrome, while in the group 2 (n=294), only urolithia-sis was diagnosed without metabolic syndrome. In both groups, depending on the stone composi-tion, in addition to general measures, specific stone prevention was carried out, which included die-tary regimen and drug therapy. RESULTS: Uric acid excretion after 6 months of therapy in patients with urolithiasis and meta-bolic syndrome decreased from 9.8+/-1.8 to 3.9+/-1.1 mmol/l, urinary excretion of citrates and urine acidity increased from 0.8 +/-0.6 to 2.5+/-0.8 mmol/l and from 5.4+/-0.5 to 6.3+/-0.5, respectively, while serum uric acid level decreased from 451.4+/-15.1 up to 385.2+/-16.2 mmol/l. In the group of patients who, in addition to prescribing stone prevention, underwent correction of the metabolic syndrome, uric acid excretion after 3 months decreased by half: from 9.7+/-1.9 to 5.0+/-1.2 mmol/l, urine pH and citrate excretion increased from 5.4+/-0.4 to 6.3+/-0.5 and from 0.8+/-0.5 to 2.3+/-1.0 mmol/l, respective-ly, while serum uric acid level decreased from 459.5+/-17.7 to 370.9+/-15.1 mmol/l after 6 months of treatment. CONCLUSION: The use of Febuxostat-SZ in the complex therapy of urinary stone disease showed high efficiency in normalizing urine acidity, the level of daily excretion and serum uric acid level, as well as satisfactory tolerability and a minimal profile of side effects.