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PubMed2026

Efficacy and Safety of Ultra-Low Starting Dose Febuxostat Titration in Male Patients With Primary Gout.

BACKGROUND: Since gout is a common metabolic arthritis caused by urate crystal deposition, urate-lowering therapy (ULT) is clearly indicated, but the initiation of ULT frequently causes paradoxical acute flares that in turn impair patient adherence. OBJECTIVE: This study sought to assess the effectiveness and safety of an ultra-low-dose initiation strategy for febuxostat (10&#x2009;mg/day) compared to the standard starting dose (20&#x2009;mg/day) in reducing initiation-related flares while maintaining long-term urate control. METHODS: 120 male patients with primary gout presenting with acute arthritis were randomly assigned to initiate febuxostat at 10&#x2009;mg/day (Group A) or 20&#x2009;mg/day (Group B), with protocol-mandated biweekly titration. The primary outcomes were gout flare frequency over 24&#x2009;weeks (assessed using Poisson regression), serum uric acid (SUA) target attainment, and the incidence of adverse events. RESULTS: Although both groups achieved comparable target SUA levels by week 24, Group A demonstrated a significantly lower overall flare incidence (36.7% vs. 70.0%; p&#x2009;<&#x2009;0.001), along with a greater percentage of flare-free patients (70.0% vs. 46.7%; p&#x2009;=&#x2009;0.016). Multivariable Poisson regression revealed that Group B had an approximately twofold higher risk of flares compared to Group A (Incidence Rate Ratio&#x2009;=&#x2009;1.95; p&#x2009;=&#x2009;0.012), with obese patients deriving the most pronounced benefit from the ultra-low-dose approach. To avert one additional flare, the calculated number needed to treat was 4.3. Additionally, the occurrence of clinically significant liver injury (ALT/AST >&#x2009;3&#xd7; ULN) was low in both groups, with 3.3% in Group A and 1.7% in Group B. Multivariable regression analysis confirmed that LDL-C is an independent predictor of ALT (&#x3b2;&#x2009;=&#x2009;12.90, p&#x2009;=&#x2009;0.009), while febuxostat dosage was not linked to hepatotoxicity. CONCLUSION: Initiating febuxostat at a dose of 10&#x2009;mg/day with gradual titration demonstrates a superior safety profile by effectively reducing early acute flares without compromising long-term urate control, which is particularly advantageous for high-risk cohorts, including obese patients.

Humans↗
PubMed1989

The United States experience with oral controlled-release morphine (MS Contin tablets). Parts I and II. Review of nine dose titration studies and clinical pharmacology of 15-mg, 30-mg, 60-mg, and 100-mg tablet strengths in normal subjects.

The results of nine US multicenter, sequential crossover, dose titration studies of controlled-release oral morphine (MS Contin 30 mg tablets [MSC], Purdue Frederick, Norwalk, CT) are reviewed in Part I. The studies demonstrated the prolonged analgesic efficacy of the preparation in the treatment of patients with moderate to severe cancer-related pain. Approximately 93% of the patients achieved satisfactory to excellent analgesia on a 12-hour regimen when appropriate dose titration was allowed. The remaining patients were successfully maintained on an 8-hour regimen. The preparation was well-tolerated and comparable in safety to immediate-release oral morphine. In global evaluations, MSC was judged to be significantly (P less than 0.05) more effective, and with significantly (P less than 0.05) fewer side effects than both the prestudy opioid analgesics and 4-hour immediate-release oral morphine. Patients had a broad range of morphine requirements (mean daily MSC dose, 240 mg; range, 60 mg/day to 1800 mg/day); therefore various MSC tablet strengths were developed. Part II presents three studies in which the MSC formulations (15-mg, 60-mg, and 100-mg tablets) were compared to the 30-mg tablet within three randomized, single-dose, two-way crossover, analytically blinded bioavailability protocols, to determine bioequivalence and dose proportionality. The maximum morphine concentration, time of maximum morphine concentration, and area under the plasma morphine versus 12-hour and 24-hour time curve (AUC 0.12; AUC 0.24) were determined in each study. There were no significant differences between the values associated with MSC 1 X 30 mg tablet and 2 X 15 mg tablets (study 1), MSC 2 X 30 mg tablets and 1 X 60 mg tablet (study 2), and MSC 3 X 30 mg tablets and 1 X 100 mg tablet (study 3, values adjusted to dose of 90 mg), except for one marginally significant difference in study 3 (AUC 0.24; P = 0.04) which was not clinically or biopharmaceutically significant. The results showed that MSC 15-mg, 30-mg, 60-mg, and 100-mg dosage strengths are bioequivalent and dose proportional, and, therefore, therapeutically interchangeable. It was concluded that with routine assessment of the patient and adherence to the principles of analgesic dosing, MSC can be successfully used to control cancer-related pain. Furthermore, the availability of various MSC tablet strengths can be expected to facilitate the analgesic management of a patient population with widely differing opioid requirements.

Administration, Oral↗
PubMed2006

Elucidating the binding thermodynamics of 8-anilino-1-naphthalene sulfonic acid with the A-state of alpha-lactalbumin: an isothermal titration calorimetric investigation.

Isothermal titration calorimetry has been used to demonstrate that the heat profile associated with the binding of 8-anilino-1-naphthalene sulfonic acid (ANS) with the acid induced molten globule state (A-state) of alpha-lactalbumin (alpha-LA) is different from that with the native and denatured states of the protein. The results corroborate the spectroscopic observations that ANS binds more strongly to the partially folded states of the protein compared to that with the native and denatured states. ANS binds to the A-state of alpha-LA at two independent binding sites that remain nearly the same in the temperature range of 10-35 degrees C. The number of moles of ANS binding at site 1 at 10 degrees C is 14.0+/-0.2 and remains nearly the same with rise in temperature. However, the number of moles of ANS molecules binding at site 2 show an increase from 1.6+/-0.2 at 10 degrees C to 4.1+/-0.1 at 35 degrees C. The deviation of the slope of enthalpy-entropy compensation plot from unity and nonadherence to van't Hoff dictates implies that the binding sites on the A-state of alpha-LA for ANS are not well defined and specific; rather, these binding sites are formed due to greater exposure of hydrophobic clusters in the A-state of the protein. The results for the first time demonstrate the use of isothermal titration calorimetry in characterizing the A-state of alpha-LA both qualitatively and quantitatively.

Anilino Naphthalenesulfonates↗
PubMed2002

Acetoclastic methanogenic activity measurement by a titration bioassay.

A titration bioassay, designed to accurately determine the activity of acetoclastic methanogens, is described that also allows evaluation of inhibition due to potential toxicants on the active biomass. The instrument is made of a pH-stat connected to an anaerobic batch reactor. Acetate is blended and mixed with anaerobic sludge in the reactor where a 1:1 N2 and CO2 mixture is sparged at the beginning of each test. As the acetoclastic methanogens consume acetate, the pH increase, and the titration unit adds acetic acid and keeps the pH constant. The rate of titrant addition is directly proportional to the methanogenic activity. A very useful feature of the system is its potential to operate for long periods (days) at constant pH and substrate (acetate) concentration. The theoretical background and principle of operation are described as well as some of the practical problems encountered with the use of the instrument. Estimation of kinetic constants for an anaerobic culture according to the Michaelis-Menten model is presented. Examples of inhibition by inorganics (NaCl) and chlorinated solvents (chloroform) are also given.

Acetates↗
PubMed2002

Active site titration as a tool for the evaluation of immobilization procedures of penicillin acylase.

Native and immobilized preparations of penicillin acylase from Escherichia coli and Alcaligenes faecalis were studied using an active site titration technique. Knowledge of the number of active sites allowed the calculation of the average turnover rate of the enzyme in the various preparations and allowed us to quantify the contribution of irreversible inactivation of the enzyme to the loss of catalytic activity during the immobilization procedure. In most cases a loss of active sites as well as a decrease of catalytic activity per active site (turnover rate) was observed upon immobilization. Immobilization techniques affected the enzymes differently. The effect of increased loading of penicillin acylase on the average turnover rate was determined by active site titration to assess diffusion limitations in the carrier.

Alcaligenes↗
PubMed2002

Characterization of electrostatic binding sites of extracellular polymers by linear programming analysis of titration data.

Electrostatic binding sites of extracellular polymeric substances (EPS) were characterized from titration data using linear programming analysis. Test results for three synthetic solutions of given solutes comprising amino, carboxyl, and phenolic groups indicated that this method was able to identify the electrostatic binding sites. For the six sites with pK(a) between 3 and 10, the estimated pK(a) deviated 0.11 +/- 0.09 from the theoretical values, and the estimated concentrations deviated 3.0% +/- 0.9% from the actual concentrations. Two EPS samples were then extracted from a hydrogen-producing sludge (HPS) and a sulfate-reducing biofilm (SRB). Analysis of charge excess data in titration from pH 3 to 11 indicated that the EPS of HPS comprised of five electrostatic binding sites with pK(a) ranging from 3 to 11. The pK(a) values of these binding sites and the possible corresponding functional groups were pK(a) 4.8 (carboxyl), pK(a) 6.0 (carboxyl/phosphoric), pK(a) 7.0 (phosphoric), pK(a) 9.8 (amine/phenolic), and pK(a) 11.0 (hydroxyl). EPS of the SRB comprised five of similar binding sites (with corresponding pK(a) values of 4.4, 6.0, 7.4, 9.4, and 11.0), plus one extra site at pK(a) 8.2, which was likely corresponding to the sulfhydryl group. The total electrostatic binding site concentration of EPS extracted from HPS were 10.88 mmol/g-EPS, of which the highest concentration was from the site of pK(a) 11.0. The corresponding values for the EPS extracted from SRB were 16.44 mmol/g-EPS and pK(a) 4.4. The total concentrations of electrostatic binding sites found in this study were 20- to 30-fold of those reported for bacterial cell surface, implying that EPS might be more crucial in biosorption of metals than bacterial cell surface in wastewater treatment and in bioremediation.

Bacteria↗
PubMed2004

Determination of binding constants of cyclodextrin inclusion complexes with amino acids and dipeptides by potentiometric titration.

Cyclodextrins are well known for their ability to separate enantiomers of drugs, natural products, and other chiral substances using HPLC, GC, or CE. The resolution of the enantiomers is due to the formation of diastereomeric complexes between the cyclodextrin and the pairs of enantiomers. The aim of this study was to determine the binding constants of the complexes between alpha- and beta-cyclodextrin and the enantiomers of a series of aliphatic and aromatic amino acids, and dipeptides, using a potentiometric titration method. The results of this method are compared to other methods, and correlated to findings in cyclodextrin-modified capillary electrophoresis and possible complex structures. Potentiometric titration was found to be an appropriate tool to determine the binding constants of cyclodextrin inclusion complexes.

Amino Acids↗
PubMed1976

Titration of nicotine intake with full-length and half-length cigarettes.

Titration, the self-regulation of nicotine intake, was studied in 12 smokers by gas chromatograph assays of urinary nicotine levels. Results demonstrated that excretion of urinary nicotine in the proximal condition (half cigarette close to the filter) did not differ significantly from the whole cigarette condition; however, less nicotine was excreted in the distal condition (half cigarette farther from the filter) because of a rod filtration effect. Subjects extracted proportionately more nicotine from the half than from the whole cigarettes; titration was approximately the same in both half-cigarette conditions. On scales of strength and satisfaction, full-length cigarettes were given the highest rating, followed by proximal and then distal cigarettes.

Adult↗
PubMed2005

Biological microbeads for flow-cytometric immunoassays, enzyme titrations, and quantitative PCR.

BACKGROUND: Introduction of microbeads into flow-cytometry has created a new scenario, making quantitative measurement of molecules dispersed in a homogeneous phase, with an extremely wide realm of already realized and potential applications possible. Development of this field has lead to specialized instrumentation and microbead arrays, dedicated to certain applications. METHODS: Formaldehyde-fixed yeast and bacterial cells were conjugated with avidin and applied as microbeads, to establish a simple, convenient, flexible, and inexpensive flow-cytometric platform for various immunological and biochemical assays. RESULTS: We have tested these "biological microbeads" for the simultaneous titration of human alpha-fetoprotein (AFP) and human Chorionic Gonadotropin (betahCG) hormone levels, for the titration of proteolytic and nucleolytic (restriction) enzymes, and for quantitative PCR, using biotinylated and fluorescent primers. CONCLUSIONS: The use of biological microbeads for various immunological and biochemical assays has been demonstrated. The flow-cytometric methods proved to be at least as sensitive as the standard biochemical or immunological tests. For proteinase K activity measurements, a single enzyme molecule in the sample could be detected. The sensitivity, versatility, and low cost of the assays may advance flow-cytometry to become a central methodological platform in most laboratories. The biological microbeads offer virtually unlimited possibilities for fluorescent labeling (addressing), conjugation of ligand binding molecules, and they are easy to handle and perform well in a multiplex format.

Avidin↗
PubMed1989

Distortion of the electrophoretic titration curves of some proteins.

The electrophoretic titration curves of complex mixtures of vitamin K-dependent human blood proteins and proteins of Bothrops asper venom were investigated. In both protein mixtures some curves exhibited marked distortions such as additional maxima and minima when Pharmalyte 3-10 carrier ampholytes were used for isoelectric focusing in agarose gels. The distortions result from an unspecific interactions between some carrier ampholyte constituents with particular proteins. The interacting carrier ampholyte components could be completely removed by binding to albumin and ultrafiltration through a UM-2 Amicon membrane with resultant regular titration curves. The interacting carrier ampholyte species were only partially removed by ultrafiltration through a UM-2 membrane without incubation with albumin.

Animals↗
PubMed1995

Differentiation of scombroid fish species (tunas, bonitos and mackerels) by isoelectric focusing, titration curve analysis and native polyacrylamide gel electrophoresis of sarcoplasmic proteins.

Differentiation of scombroid fishes was possible by electrophoresis of sarcoplasmic proteins using either isoelectric focusing (IEF), titration curve analysis, or native polyacrylamide gel electrophoresis (PAGE). By IEF with Phast-Gels 3-9 species specific patterns, characterized by a few bands in the cathodal part of the gels, were obtained. This type of gel was also used for titration curve analysis. Here, too, the closely related species Thunnus thynnus and T. albacares gave different protein patterns. Native PAGE, native cathodal electrophoresis in Clean Gel 10% with buffer pH 5.5, proved to be a fast and simple method for differentiation of scombroid fishes. As most of the prominent sarcoplasmic proteins of these species have pIs in the neutral or alkaline pH range, they are positively charged at pH 5.5 and move to the cathode.

Animals↗
PubMed1996

Isoelectric focusing and titration curves in biomedicine and in agrofood industries: a multimedia teaching program.

The aim of this 45 min, 60 megabyte, modular program is to initiate students, scientists and engineers of biotechnology, biomedicine and agrofood industries into isoelectric focusing (IEF) and titration curves for analytical (e.g. IEF, zone electrophoresis, isotachophoresis, electrotransfer) and preparative (e.g. ion-exchange chromatography, chromatofocusing) application of charge-dependent methods. For advanced teaching, the following theoretical and practical aspects may be of interest: pH gradient engineering, IEF resolving power, generation of pH gradient, sample-ampholyte interactions, pH gradient drift, immobilized pH gradients (IPG), IPG-two-dimensional (2-D) electrophoresis, preparative methods with multi-compartments and IPG membranes, capillary IEF, isozyme analysis, etc.). The program associates fixed and animated drawings, and computer-assisted simulations, with spoken and written commentaries (in English). It is illustrated with numerous IEF gel patterns and titration curves and some video sequences to be run on a multimedia PC with MS Windows 3.1 (or later releases) as the only software. The linear presentation of the program may be used directly on the PC, or may be projected on a screen from the PC, for small classes or for a larger audience (200 persons). Its development as an interactive multimedia program is in progress and will soon be available on the Internet.

Computer-Assisted Instruction↗
PubMed1988

Antihypertensive efficacy of cetamolol: a dose-titrated study.

This double-blind, placebo-controlled, randomized multicenter study evaluated the antihypertensive efficacy and safety of cetamolol hydrochloride in 108 patients diagnosed as having mild to moderate hypertension. After a placebo lead-in period, patients received either cetamolol 5-10-15 mg/d (low dose), cetamolol 15-25-50 mg/d (high dose), or placebo, once daily for four weeks. Patients began at the lowest dose and were titrated to higher doses based on the first two assessments of diastolic blood pressure and heart rate, which were conducted each week after double-blind treatment was dispensed. After four weeks of treatment 82.4%, 81.3%, and 93.3% of the low-dose group, high-dose group, and placebo group, respectively, were titrated to the maximum dose level. After four weeks of treatment and 24 hours since the patient's last dose, both cetamolol groups showed a significantly greater (P less than or equal to .05) reduction in supine systolic/diastolic blood pressure (-18.1 +/- 2.3/-9.2 +/- 1.5 mm Hg [low dose] and -17.3 +/- 2.3/-8.3 +/- 1.6 mm Hg [high dose]) than the placebo group (-9.9 +/- 2.5/-3.5 +/- 1.7 mm Hg). In general, the changes in standing (stabilized) systolic and diastolic blood pressure were similar to those seen in supine measurements. Significantly more patients receiving cetamolol than those receiving placebo showed a "good response" (a decrease in diastolic blood pressure of 10 mm Hg or more or measuring less than 90 mm Hg with a decrease of at least 4 mm Hg).(ABSTRACT TRUNCATED AT 250 WORDS)

Acetamides↗
PubMedDate not supplied

Survey of the year 2004: literature on applications of isothermal titration calorimetry.

The market for commercially available isothermal titration calorimeters continues to grow as new applications and methodologies are developed. Concomitantly the number of users (and abusers) increases dramatically, resulting in a steady increase in the number of publications in which isothermal titration calorimetry (ITC) plays a role. In the present review, we will focus on areas where ITC is making a significant contribution and will highlight some interesting applications of the technique. This overview of papers published in 2004 also discusses current issues of interest in the development of ITC as a tool of choice in the determination of the thermodynamics of molecular recognition and interaction.

Calorimetry↗
PubMed1975

Determination of stability constants of stannous fluoride complexes by potentiostatic titration.

The stability constants for stannous fluoride complexes were determined by potentiostatic titration. The method involves incremental additions of fluoride wherein each addition is followed by titration with stannous such that there is no change in the electromotive force developed between the fluoride ion and the reference electrodes. The values obtained were beta1 equals 4 times 10-3, b2 equals 1.1 times 10-7, and b3 equals 1 times 10-9. The results of this work suggest that the potentiostatic method wound be useful for determining stability constants in complexation systems involving an ion for which a specific on electrode is available.

Drug Stability↗
PubMed1975

Differentiating nonaqueous titration of aspirin, acetaminophen, and salicylamide mixtures.

Mixtures containing aspirin, acetaminophen, and salicylamide were assayed potentiometrically by nonaqueous titration. The difference in pKa values for these weak acids was sufficient to permit successful differentiation. The titrant was tetrabutylammonium hydroxide, and the titration solvent was dimethylformamide. The procedure was applied to commercial dosage forms.

Acetaminophen↗
PubMed1978

Synthesis of methaqualone and its diphasic titration in pure and tablet forms.

A one-step synthesis of methaqualone from N-acetylanthranilic acid and o-toluidine in the absence of a catalyst is described. A rapid diphasic titration procedure for its microestimation in pure and tablet forms, using dioctyl sodium sulfosuccinate and dimethyl yellow screened with oracet blue B, is proposed. The data were compared with those obtained from nonaqueous titration methods.

Methaqualone↗