Tumour lysis syndrome.

Tumour lysis syndrome (TLS) represents a critical oncological emergency characterized by extensive tumour cell breakdown, leading to the swift release of intracellular contents into the systemic circulation, outpacing homeostatic mechanisms. This process results in hyperuricaemia (a by-product of intracellular DNA release), hyperkalaemia, hyperphosphataemia, hypocalcaemia and the accumulation of xanthine. These electrolyte and metabolic imbalances pose a significant risk of acute kidney injury, cardiac arrhythmias, seizures, multiorgan failure and, rarely, death. While TLS can occur spontaneously, it usually arises shortly after the initiation of effective treatment, particularly in patients with a large cancer cell mass (defined as ≥500 g or ≥300 g/m2 of body surface area in children). To prevent TLS, close monitoring and hydration to improve renal perfusion and urine output and to minimize uric acid or calcium phosphate precipitation in renal tubules are essential. Intervention is based on the risk of a patient of having TLS and can include rasburicase and allopurinol. Xanthine, typically enzymatically converted to uric acid, can accumulate when xanthine oxidases, such as allopurinol, are administered during TLS management. Whether measurement of xanthine is clinically useful to optimize the use of allopurinol or rasburicase remains to be determined.

Population Pharmacokinetics and Target Attainment of Allopurinol and Oxypurinol Before, During, and After Cardiac Surgery with Cardiopulmonary Bypass in Neonates with Critical Congenital Heart Disease.

BACKGROUND: The CRUCIAL trial (NCT04217421) is investigating the effect of postnatal and perioperative administration of allopurinol on postoperative brain injury in neonates with critical congenital heart disease (CCHD) undergoing cardiac surgery with cardiopulmonary bypass (CPB) shortly after birth. OBJECTIVE: This study aimed to characterize the pharmacokinetics (PK) of allopurinol and oxypurinol during the preoperative, intraoperative, and postoperative phases in this population, and to evaluate target attainment of the current dosing strategy. METHODS: Nonlinear mixed-effects modeling was used to develop population PK models in 14 neonates from the CRUCIAL trial who received up to five intravenous allopurinol administrations throughout the postnatal and perioperative periods. Target attainment was defined as achieving an allopurinol concentration >2 mg/L in at least two-thirds of the patients during the first 24 h after birth and between the start and 36 h after cardiac surgery with CPB. RESULTS: A two-compartment model for allopurinol was connected to a one-compartment model for oxypurinol with an auto-inhibition effect on the conversion, which best described the PK. In a typical neonate weighing 3.5 kg who underwent cardiac surgery at a postnatal age (PNA) of 5.6 days, the clearance (CL) of allopurinol and oxypurinol at birth was 0.95 L/h (95% confidence interval 0.75-1.2) and 0.21 L/h (0.17-0.27), respectively, which subsequently increased with PNA to 2.97 L/h and 0.41 L/h, respectively, before CPB. During CPB, allopurinol and oxypurinol CL decreased to 1.38 L/h (0.9-1.87) and 0.12 L/h (0.05-0.22), respectively. Post-CPB, allopurinol CL increased to 2.21 L/h (1.74-2.83), while oxypurinol CL dropped to 0.05 L/h (0.01-0.1). Target attainment was 100%, 53.8%, and 100% at 24 h postnatally, 24 h after the start of CPB, and 36 h after the end of cardiac surgery, respectively. The combined concentrations of allopurinol and oxypurinol maintained ≥ 90% inhibition of xanthine oxidase (IC90XO) throughout the postnatal and perioperative period. CONCLUSIONS: The minimal target concentration of allopurinol was not achieved at every predefined time interval in the CRUCIAL trial; however, the dosing strategy used was deemed adequate, since it yielded concentrations well exceeding the IC90XO. The decreased CL of both compounds during CPB suggests influence of the hypothermia, hemofiltration, and the potential sequestration of allopurinol in the circuit. The reduced CL of oxypurinol after CPB is likely attributable to impaired kidney function.

Urate lowering therapy in patients starting hemodialysis limit gout flares occurrence: ten years retrospective study.

BACKGROUND: Uncontrolled gout can cause articular impairment but is also associated with a global and cardiovascular excess mortality, especially in dialysis population. Data documented within existing research is not conclusive regarding gout flares evolution during hemodialysis and their control by urate lowering therapy (ULT). Without clear guidelines concerning hemodialysis patients management with chronic gout, this study proposes to investigate whether gout flare incidence reduction could be observed on this population treated by urate lowering therapy versus patients without treatment. METHODS: We performed a retrospective cohort study in two hemodialysis centers in France. Were selected patients over 18 years old with a gout history who started hemodialysis between January 2005 and September 2015. Demographics and clinicals data were recorded at hemodialysis start and throughout 5 years of follow up. Gout flare was defined as presence of uric acid crystal in joint punction or clinically diagnosed as such with a colchicine prescription. All statistical analysis were performed in SAS® version 9.4 (SAS Institute Inc., Cary, NC). RESULTS: One hundred eighty-one patients have been included, mean age at dialysis initiation was 68.6 years (± 12.4) with 72% of men, 54% were treated by ULT: 89.7% by allopurinol and 9.3% by febuxostat. One patient received both treatments successively. After hemodialysis initiation, 35.36% patients had experienced at least one gout flare. The appearance of at least one gout flare concerned 50% of patients in no ULT group and 22.68% patients in ULT group (p = 0.0002). Dialysis efficiency was measured at regular interval during follow-up and was similar in both groups. To study the association strength between clinical factors and gout flares occurrences, a Cox model was performed; ULT is a protector factor of gout flare (HR:0,42, CI 95: 0,25-0,71). The proportion of serum urate values within the target (median 53% vs 29.3%, p < 0.0001) was significantly higher in ULT group versus no ULT group (median 53% vs 29.3%, p < 0.0001). CONCLUSION: Urate lowering therapy limit new gout flares occurrence in hemodialysis patients with gout historyCollaboration between rheumatologists and nephrologists may help to update guidelines for urate-lowering therapies in patients on dialysis.

Systemic allopurinol administration reduces malondialdehyde, interleukin 6, tumor necrosis factor α, and increases vascular endothelial growth factor in random flap Wistar rats exposed to nicotine.

INTRODUCTION: Smoking poses a risk to flap viability, with nicotine being a major contributor to the formation of free radicals. Allopurinol, known for its antioxidant properties, has been shown to enhance tissue survival in ischemic conditions by reducing the production of reactive oxygen species (ROS). This study aims to assess the impact of allopurinol on the viability and success of skin flaps in Wistar rats exposed to nicotine. METHODS: This study examined skin flap survival in nicotine-exposed rats treated with allopurinol. Twenty-eight rats were separated into two groups. During 1 month of nicotine exposure, the treatment group received systemic allopurinol 7 days before and 2 days after the flap procedure, while the control group received no allopurinol. Pro-angiogenic factors, proinflammatory factors, anti-inflammatory factors, and oxidative markers were assessed on the 7th day after the flap procedure using enzyme-linked immunosorbent assay method. Macroscopic flap viability was evaluated on the 7th day using Image J photos. RESULTS: As an oxidative marker, malondialdehyde levels were significantly lower in rats given allopurinol than in controls (P < 0.001). The levels of interleukin 6 and tumor necrosis factor α, as markers of inflammatory factors, were significantly lower in the group of rats given allopurinol compared to controls (P < 0.001). The level of angiogenesis in rats given allopurinol, measured by vascular endothelial growth factor levels, was also higher in the treatment group compared to controls (P < 0.001). Macroscopically, the percentage of distal flap necrosis in Wistar rats given allopurinol was lower and statistically significant compared to controls (P < 0.001). CONCLUSIONS: Xanthine oxidoreductase is part of a group of enzymes involved in reactions that produce ROS. Allopurinol, as an effective inhibitor of the xanthine oxidase enzyme, can reduce oxidative stress by decreasing the formation of ROS. This reduction in oxidative stress mitigates the risk of ischemic-reperfusion injury effects and significantly increases the viability of Wistar rat flaps exposed to nicotine.

Easing the way to achieving target serum urate in people with gout: protocol for a non-inferiority randomised strategy trial using an allopurinol dosing model in Aotearoa/New Zealand (the Easy-Allo Study).

INTRODUCTION: Gout is one of the most common forms of arthritis worldwide. Gout is particularly prevalent in Aotearoa/New Zealand and is estimated to affect 13.1% of Maori men, 22.9% of Pacific men and 7.4% of New Zealand European men. Effective long-term treatment requires lowering serum urate to <0.36 mmol/L. Allopurinol is the most commonly used urate-lowering medication worldwide. Despite its efficacy and safety, the allopurinol dose escalation treat-to-target serum urate strategy is difficult to implement and there are important inequities in allopurinol prescribing in Aotearoa. The escalation strategy is labour intensive, time consuming and costly for people with gout and the healthcare system. An easy and effective way to dose-escalate allopurinol is required, especially as gout disproportionately affects working-age Maori men and Pacific men, who frequently do not receive optimal care. METHODS AND ANALYSIS: A 12-month non-inferiority randomised controlled trial in people with gout who have a serum urate ≥ 0.36 mmol/l will be undertaken. 380 participants recruited from primary and secondary care will be randomised to one of the two allopurinol dosing strategies: intensive nurse-led treat-to-target serum urate dosing (intensive treat-to-target) or protocol-driven dose escalation based on dose predicted by an allopurinol dosing model (Easy-Allo). The primary endpoint will be the proportion of participants who achieve target serum urate (<0.36 mmol/L) at 12 months. ETHICS AND DISSEMINATION: The New Zealand Northern B Health and Disability Ethics Committee approved the study (2022 FULL 13478). Results will be disseminated in peer-reviewed journals and to participants. TRIAL REGISTRATION NUMBER: ACTRN12622001279718p.

Microbiological Stability of Allopurinol, Clindamycin Hydrochloride, Naltrexone Hydrochloride, Spironolactone and Ursodiol Oral Liquids Compounded in PCCA Base, SuspendIt®.

The individual physicochemical stabilities of Allopurinol, Clindamycin Hydrochloride, Naltrexone Hydrochloride, Spironolactone and Ursodiol in the proprietary suspending vehicle PCCA SuspendIt® have been previously studied and published by the author. Accordingly, Beyond-Use-Dates (BUDs) of 180 days were assigned to the five drugs based on the results of the respective studies. The data were donated to the United States Pharmacopeia (USP) for possible adoption as Official Compounded Drug Monographs. Following an extensive review process, all five studies were approved and published by the USP. However, due to a lack of microbiological stability information, the BUDs were limited to 90 days. The current study was undertaken as a follow-up project to determine the microbiological stability of these five drugs in PCCA SuspendIt® utilizing the same compounding procedures from the original studies. A stable extemporaneous product is defined as one that retains at least 90% of the initial drug concentration throughout the sampling period and is protected against microbial growth. The goal was to provide a viable, compounded alternative for Allopurinol, Clindamycin Hydrochloride, Naltrexone Hydrochloride, Spironolactone and Ursodiol in a thixotropic liquid dosage form, with an extended BUD of 6 months to meet patient needs. Given that the physical and chemical stabilities of all five drugs have been previously established and adopted by the USP as official compounded monographs, additional microbiological stability data would allow the official BUDs in the USP to be extended to 180 days to conform to the physicochemical stabilities. The current study showed that the preservative system in PCCA SuspendIt® successfully protected all the suspensions from growth of challenge microorganisms per the USP Chapter <51> AME Test. The results of the current study combined with the previous physicochemical studies demonstrate the following: Allopurinol is physically, chemically and microbiologically stable in PCCA SuspendIt for 180 days in the refrigerator and at room temperature over a bracketed allopurinol concentration range of 10 - 20 mg/mL. Clindamycin Hydrochloride is physically, chemically and microbiologically stable in PCCA SuspendIt for 180 days in the refrigerator and at room temperature at a concentration of 10-mg/mL of clindamycin. Naltrexone Hydrochloride is physically, chemically and microbiologically stable in PCCA SuspendIt for 180 days in the refrigerator and at room temperature, over a bracketed naltrexone hydrochloride concentration range of 0.5 - 5.0 mg/mL. Spironolactone is physically, chemically and microbiologically stable in PCCA SuspendIt for 180 days in the refrigerator and at room temperature at a concentration of 5 mg/mL of spironolactone. Ursodiol is physically, chemically and microbiologically stable in PCCA SuspendIt for 180 days in the refrigerator and at room temperature, over a bracketed ursodiol concentration range of 50 - 100 mg/mL. Taken collectively, the current study in conjunction with the earlier studies provide viable, compounded alternatives for Allopurinol, Clindamycin Hydrochloride, Naltrexone Hydrochloride, Spironolactone and Ursodiol in the suspending vehicle PCCA SuspendIt in liquid dosage forms, with an extended beyond-use-date to meet patient needs.

ALLOPURINOL TREATMENT IMPROVES INSULIN RESISTANCE IN NON-DIABETIC PATIENTS WITH RENAL STONE.

Hyperuricemia is an objective risk factor of derangement of fasting serum glucose and type 2 diabetes (T2D), yet whether hyperuricemia has a causative influence on insulin resistance is still debatable. In this study, we tested the hypothesis that lowering uric acid in hyperuricemic nondiabetic subjects might improve insulin resistance. Patients with renal stone and hyperuricemia (n=15) were recruited from the private clinic of Ib-Sina Local Teaching Hospital in Mosul city and prospectively placed on allopurinol (300mg/day) for 6 months. Serum uric acid (SUA), fasting serum glucose (FSG), fasting insulin, and C-peptide were measured using commercial kits. Results confirmed that allopurinol has significantly (P<0.05) reduced c-peptide and insulin together with a non-significant (p>0.05) reduction of serum glucose levels. In conclusion, allopurinol has improved insulin level and glycemic control in a healthy individual, these findings could be used as a template for using allopurinol in diabetic patients to improve glycemic control or future studies could be directed toward structural modification of allopurinol which hopefully might lead to innovation of new antidiabetic drugs.

Improved Preservation of Rat Small Intestine Transplantation Graft by Introduction of Mesenchymal Stem Cell-Secreted Fractions.

Segmental grafts from living donors have advantages over grafts from deceased donors when used for small intestine transplantation. However, storage time for small intestine grafts can be extremely short and optimal graft preservation conditions for short-term storage remain undetermined. Secreted factors from mesenchymal stem cells (MSCs) that allow direct activation of preserved small intestine grafts. Freshly excised Luc-Tg LEW rat tissues were incubated in preservation solutions containing MSC-conditioned medium (MSC-CM). Preserved Luc-Tg rat-derived grafts were then transplanted to wild-type recipients, after which survival, injury score, and tight junction protein expression were examined. Luminance for each graft was determined using in vivo imaging. The findings indicated that 30-100 and 3-10 kDa fractions of MSC-CM have superior activating effects for small intestine preservation. Expression of the tight-junction proteins claudin-3, and zonula occludens-1 preserved for 24 h in University of Wisconsin (UW) solution containing MSC-CM with 50-100 kDa, as shown by immunostaining, also indicated effectiveness. Reflecting the improved graft preservation, MSC-CM preloading of grafts increased survival rate from 0% to 87%. This is the first report of successful transplantation of small intestine grafts preserved for more than 24 h using a rodent model to evaluate graft preservation conditions that mimic clinical conditions.

Multicentre study and systematic review: Allopurinol exposure during pregnancy.

BACKGROUND: Data about the safety of allopurinol in pregnant women are sparsely reported. AIMS: To investigate the risk of adverse pregnancy outcome and congenital abnormalities after in utero exposure to allopurinol in inflammatory bowel disease (IBD) pregnancies and in general. METHODS: We collected safety data of patients with IBD who were treated with allopurinol during pregnancy between January 2013 and March 2022. Additionally, we performed a systematic review about the teratogenic potential of allopurinol. RESULTS: We collected data from 42 allopurinol-exposed pregnancies, including one twin pregnancy; in all women, allopurinol was combined with a thiopurine. Six pregnancies (14.3%) resulted in miscarriage and one in stillbirth at 32 weeks. A congenital anomaly was observed in one newborn (coarctation of the aorta discovered postpartum). Three pregnancies, including the twin pregnancy, ended in moderate preterm delivery and one in very preterm delivery. Five neonates (15.2%) were small for gestational age. From our literature search, we identified an additional 102 allopurinol-exposed pregnancies resulting in 129 live births, including 36 infants from our cohort. Ten infants (7.8%) were born with a congenital anomaly. Two (1.6%) had a comparable pattern of multiple anomalies. The systematic review sub-analysis including only infants born to mothers with IBD (n = 76) revealed that 2.6% of infants had congenital anomalies after in utero exposure to a low dose of allopurinol. CONCLUSIONS: Overall, the teratogenicity of allopurinol remains inconclusive. Children conceived by mothers treated for IBD with allopurinol/thiopurine co-therapy do not seem to have an increased risk of congenital anomalies.

Randomised, double-blind, placebo-controlled study evaluating the effect of allopurinol on the risk of cardiovascular events in patients with high and very high cardiovascular risk, including the presence of long-COVID-19 syndrome: the ALL-VASCOR study protocol.

INTRODUCTION: Numerous studies, but not all, have suggested a positive effect of allopurinol on the cardiovascular system. The randomised, double-blind, placebo-controlled study evaluating the effect of allopurinol on the risk of cardiovascular events in patients with high and very high cardiovascular risk, including the presence of long-COVID-19 syndrome (ALL-VASCOR) study aims to evaluate the efficacy of allopurinol therapy for improving cardiovascular outcomes in patients at high and very high cardiovascular risk excluding ischaemic heart disease. This is particularly important due to the high cost of cardiovascular disease treatment and its status as one of the leading causes of mortality. METHODS AND ANALYSIS: The ALL-VASCOR study is a randomised, double-blind, placebo-controlled, multicentre trial that examines the effect of allopurinol therapy (200-500 mg of allopurinol daily) versus an equivalent dose of placebo on the risk of cardiovascular events in 1116 patients aged 40-70 with serum uric acid levels above 5 mg/dL at high and very high risk of cardiovascular disease. The ALL-VASCOR study will also assess the occurrence of long-COVID-19 syndrome. The study will measure primary and secondary as well as additional endpoints and the planned intervention will end on 31 July 2028 unless advised otherwise by the Safe Monitoring Board or other applicable authorities. Participant recruitment is planned to begin in March 2024 in Poland. ETHICS AND DISSEMINATION: The study was ethically approved by the Bioethics Committee of Poznan University of Medical Sciences (No 03/23, 12 January 2023). The results are expected after 2028 and will be disseminated in peer-reviewed journals and at international conferences. PROTOCOL VERSION NUMBER: 01-15 November 2022. TRIAL REGISTRATION NUMBER: EudraCT: 2022-003573-32, 27 October 2022, ClinicalTrials: NCT05943821, 13 July 2023.

Effects of allopurinol and febuxostat on uric acid transport and transporter expression in human umbilical vein endothelial cells.

Uric acid induces radical oxygen species formation, endothelial inflammation, and endothelial dysfunction which contributes to the progression of atherosclerosis. Febuxostat inhibits BCRP- and allopurinol stimulates MRP4-mediated uric acid efflux in human embryonic kidney cells. We hypothesized that endothelial cells express uric acid transporters that regulate intracellular uric acid concentration and that modulation of these transporters by febuxostat and allopurinol contributes to their different impact on cardiovascular mortality. The aim of this study was to explore a potential difference between the effect of febuxostat and allopurinol on uric acid uptake by human umbilical vein endothelial cells. Febuxostat increased intracellular uric acid concentrations compared with control. In contrast, allopurinol did not affect intracellular uric acid concentration. In line with this observation, febuxostat increased mRNA expression of GLUT9 and reduced MRP4 expression, while allopurinol did not affect mRNA expression of these uric acid transporters. These findings provide a possible pathophysiological pathway which could explain the higher cardiovascular mortality for febuxostat compared to allopurinol but should be explored further.

Exploring Asphodelus microcarpus as a source of xanthine oxidase inhibitors: Insights from in silico and in vitro studies.

Xanthine oxidase (XO) plays a critical role in purine catabolism, catalyzing the conversion of hypoxanthine to xanthine and xanthine to uric acid, contributing to superoxide anion production. This process is implicated in various human diseases, particularly gout. Traditional XO inhibitors, such as allopurinol and febuxostat, while effective, may present side effects. Our study focuses on Asphodelus microcarpus, a plant renowned for traditional anti-inflammatory uses. Recent investigations into its phenolic-rich flowers, notably abundant in luteolin derivatives, reveal its potential as a natural source of XO inhibitors. In the present research, XO inhibition by an ethanolic flowers extract from A. microcarpus is reported. In silico docking studies have highlighted luteolin derivatives as potential XO inhibitors, and molecular dynamics support that luteolin 7-O-glucoside has the highest binding stability compared to other compounds and controls. In vitro studies confirm that luteolin 7-O-glucoside inhibits XO more effectively than the standard inhibitor allopurinol, with an IC50 value of 4.8 µg/mL compared to 11.5 µg/mL, respectively. These findings underscore the potential therapeutic significance of A. microcarpus in managing conditions related to XO activity. The research contributes valuable insights into the health-promoting properties of A. microcarpus and its potential application in natural medicine, presenting a promising avenue for further exploration in disease management.

Assessment of Bitterness in Non-Charged Pharmaceuticals with a Taste Sensor: A Study on Substances with Xanthine Scaffold and Allopurinol.

Taste sensors with an allostery approach have been studied to detect non-charged bitter substances, such as xanthine derivatives, used in foods (e.g., caffeine) or pharmaceuticals (e.g., etofylline). In this study, the authors modified a taste sensor with 3-bromo-2,6-dihydroxybenzoic acid and used it in conjunction with sensory tests to assess the bitterness of non-charged pharmaceuticals with xanthine scaffolds (i.e., acefylline and doxofylline), as well as allopurinol, an analogue of hypoxanthine. The results show that the sensor was able to differentiate between different levels of sample bitterness. For instance, when assessing a 30 mM sample solution, the sensor response to acefylline was 34.24 mV, which corresponded to the highest level of bitterness (τ = 3.50), while the response to allopurinol was lowest at 2.72 mV, corresponding to relatively weaker bitterness (τ = 0.50). Additionally, this study extended the application of the sensor to detect pentoxifylline, an active pharmaceutical ingredient in pediatric medicines. These results underscore the taste sensor's value as an additional tool for early-stage assessment and prediction of bitterness in non-charged pharmaceuticals.

Comparative Cardiovascular Risks of Febuxostat and Allopurinol in Patients with Diabetes Mellitus and Chronic Kidney Disease.

BACKGROUND Hyperuricemia, which is common in chronic kidney disease and diabetes mellitus patients, raises health concerns. Febuxostat, a first-line urate-lowering agent, prompts cardiovascular risk questions, especially in high-risk patients. This study compared the effects of febuxostat and allopurinol on cardiovascular risk in diabetes mellitus and chronic kidney disease patients. MATERIAL AND METHODS This retrospective observational cohort study, conducted using Taiwan's National Health Insurance Research Database, focused on patients diagnosed with chronic kidney disease and diabetes between January 2012 and December 2017. The study population was divided into 2 groups: allopurinol users (n=12 901) and febuxostat users (n=2997). We performed 1: 1 propensity score matching, resulting in subgroups of 2997 patients each. The primary outcomes were assessed using a competing risk model, estimating hazard ratios (HR) for long-term outcomes, including the risks of all-cause hospitalization, hospitalization for heart failure, and hospitalization for cardiovascular interventions. RESULTS Febuxostat users, compared to allopurinol users, had higher all-cause hospitalization (HR: 1.33; 95% confidence interval [CI]: 1.25 to 1.42; P<.001), hospitalization for heart failure (HR: 1.62; 95% CI: 1.43 to 1.83; P<.001), and hospitalization for cardiovascular interventions (HR: 1.51; 95% CI: 1.32 to 1.74; P<.001). Moreover, the adverse effects of febuxostat on cardiac health were consistent across most subgroups. CONCLUSIONS Use of febuxostat in patients with diabetes mellitus and chronic kidney disease is associated with higher cardiovascular risks compared to allopurinol. Prudent evaluation is essential when recommending febuxostat for this at-risk group.

Xanthine oxidase immobilized cellulose membrane-based colorimetric biosensor for screening and detecting the bioactivity of xanthine oxidase inhibitors.

Xanthine oxidase (XO) is a typical target for hyperuricemia and gout, for which there are only three commercial xanthine oxidase inhibitors (XOIs): febuxostat, topiroxostat and allopurinol. However, these inhibitors have problems such as low bioactivity and several side effects. Therefore, the development of novel XOIs with high bioactivity for the treatment of hyperuricemia and gout is urgently needed. In this work we constructed a XO immobilized cellulose membrane colorimetric biosensor (XNCM) by the TEMPO oxidation, amide bond coupling and nitro blue tetrazolium chloride (NBT) loading method. As expected, the XNCM was able to detect xanthine, with high selectivity and sensitivity by colorimetric method with a distinctive color change from yellow to purple, which can be easily observed by the naked-eye in just 8 min without any complex instrumentation. In addition, the XNCM sensor performed screening of 21 different compounds and have been successfully pre-screened out XOIs with biological activity. Most importantly, the XNCM was able to quantitatively detect the IC50 values of two commercial inhibitors (febuxostat and allopurinol). All the results confirmed that the XNCM is a simple and effective tool which can be used for the accelerated screening of XOIs and has the potential to uncover additional XOIs.

The impact of chrysanthemi indici flos-enriched flavonoid part on the model of hyperuricemia based on inhibiting synthesis and promoting excretion of uric acid.

ETHNOPHARMACOLOGICAL RELEVANCE: In recent years, in addition to hypertension, hyperglycemia, and hyperlipidemia, the prevalence of hyperuricemia (HUA) has increased considerably. Being the fourth major health risk factor, HUA can affect the kidneys and cardiovascular system. Chrysanthemi Indici Flos is a flavonoid-containing traditional Chinese patent medicine that exhibits a uric acid (UA)-lowering effect. However, the mechanisms underlying Chrysanthemi Indici Flos-enriched flavonoid part (CYM.E) mediated alleviation of HUA remain unelucidated. AIM OF THE STUDY: This study aimed to elucidate the efficacy of CYM.E in preventing and treating HUA and its specific effects on UA-related transport proteins, to explore possible mechanism. METHODS: The buddleoside content in CYM.E was determined through high-performance liquid chromatography. HUA was induced in mice models using adenine and potassium oxonate. Subsequently, mice were administered 10 mg/kg allopurinol, and 30, 60, and 90 mg/kg CYM.E to evaluate the effects of CYM.E on the of HUA mice model. Herein, plasma uric acid (UA), creatinine (CR), blood urea nitrogen (BUN), total cholesterol (TC), triglyceride (TG), high-density lipoprotein cholesterol (HDL-c), and low-density lipoprotein cholesterol (LDL-c) contents, along with serum alanine aminotransferase (ALT), and aspartate aminotransferase (AST) activities were measured. Additionally, xanthine oxidase (XOD) and adenosine deaminase (ADA) activities in the liver were determined. The histomorphologies of the liver and kidney tissues were examined through hematoxylin and eosin staining. The messenger RNA (mRNA) expression of facilitated glucose transporter 9 (GLUT9), organic anion transporter (OAT)1, OAT3, and adenosine triphosphate binding cassette subfamily G2 (ABCG2) in the kidney was assessed by real-time quantitative polymerase chain reaction. Furthermore, the expression of urate transporter 1 (URAT1), GLUT9, OAT1, and OAT3 in the kidney, OAT4, and ABCG2 proteins was determined by immunohistochemistry and western blotting. RESULTS: The buddleoside content in CYM.E was approximately 32.77%. CYM.E improved body weight and autonomous activity in HUA mice. Additionally, it reduced plasma UA, BUN, and CR levels and serum ALT and AST activities, thus improving hepatic and renal functions, which further reduced the plasma UA content. CYM.E reduced histopathological damage to the kidneys. Furthermore, it lowered plasma TC, TG, and LDL-c levels, thereby improving lipid metabolism disorder. CYM.E administration inhibited hepatic XOD and ADA activities and reduced the mRNA expression of renal GLUT9. CYM.E inhibited the protein expression of renal URAT1, GLUT9, and OAT4, and increased the mRNA and protein expression of renal OAT1, OAT3, and ABCG2. Altogether, these results show that CYM.E could inhibit the production and promote reabsorption of UA and its excretion.

Linear solvent strength model on porous graphitic carbon stationary phase using high temperature liquid chromatographic method for allopurinol related substances analysis.

A high-performance liquid chromatography (HPLC) method was developed for the analysis of Allopurinol and its Ph.Eur. impurities using a porous graphitic carbon (PGC) stationary phase. Retention behavior of solutes was studied across a wide temperature range (30-90 °C) and various gradient times (5-20 min). Analysis of the data revealed distinct retention mechanisms between reversed-phase and PGC phases. However, it was proved that the retention of Allopurinol and its Ph.Eur. impurities on PGC stationary phase can be effectively modeled using the linear solvent strength (LSS) theory. This allows for the utilization of LSS-based method development software to optimize methods under these conditions. By using commercial chromatographic modeling software, separation of Allopurinol and Ph.Eur. impurities was optimized within a large design space. At the optimized operating conditions (pH = 2.0, tG = 6 min, T = 60 °C), all solutes were separated within 6 min with baseline resolution. Comparison between predicted and experimentally measured chromatograms further confirmed the applicability of LSS theory in developing analytical methods for PGC-based HPLC systems. The presented approach offers a general framework for method development on PGC phases.

Influence of xanthine oxidase inhibitors on all-cause mortality in adults: a systematic review and meta-analysis.

Xanthine oxidase inhibitors, including allopurinol and febuxostat, are the first-line treatment of hyperuricemia. This meta-analysis investigated the association between urate-lowering therapy and all-cause mortality in different chronic diseases to match its users and non-users in a real-world setting. Overall, 11 studies were included, which reported adjusted hazard ratios for all-cause mortality over at least 12 months. Meta-analysis of all included studies showed no effect of the therapy on all-cause mortality. However, subgroup analyses showed its beneficial effect in patients with chronic kidney disease (14% risk reduction) and hyperuricemia (14% risk reduction), but not in patients with heart failure (28% risk increase). Urate-lowering therapy reduces all-cause mortality among patients with hyperuricemia and chronic kidney disease, but it seems to increase mortality in patients with heart failure and should be avoided in this subgroup.