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Objective. To investigate the influence of nonvalvular atrial fibrillation (NVAF) on the pharmacokinetic (PK) properties of the oral direct thrombin inhibitor ximelagatran and its active form, melagatran. Methods. In an open study, 12 patients with persistent NVAF and 12 age- and gender-matched, healthy control subjects received a 10-min intravenous (i.v.) infusion of 2.66 mg melagatran followed by oral ximelagatran, 36 mg twice daily, for the subsequent five study days. Plasma and urine samples for PK analyses were collected after i.v. and single and repeated oral dosing. Results. The oral absorption of ximelagatran was rapid, and maximum plasma concentrations of ximelagatran (Cmax) were achieved at about 1 h post-dosing. There were no differences between NVAF patients and controls for the area under the plasma concentration versus time curve, Cmax, half-life (t1/2), or bioavailability (F) of melagatran after oral dosing with ximelagatran. The Cmax of melagatran, formed by the rapid bioconversion of ximelagatran, occurred approximately 3 h post-dosing. The geometric means of the t1/2 for melagatran were 4.0 h and 4.2 h for the first and last doses, respectively, in patients, and 3.5 h and 3.7 h, respectively, in controls. Geometric means of F of melagatran following oral administration of ximelagatran were 22% and 24% for the first and last doses, respectively, in patients and 21% and 23%, respectively, in controls. Approximately 80% of the i.v. dose of melagatran was excreted in urine in patients and in controls. Conclusion. The PK properties of oral ximelagatran and i.v. melagatran in elderly patients with NVAF are consistent with those in matched, healthy controls. [ABSTRACT FROM AUTHOR]

The usefulness of sugar surfactants as solubilizing agents was assessed and compared to commercial polyoxyethylene-based surfactants. The sugar surfactants examined comprised of monosaccharides or disaccharides with alkyl chains ranging from C8 to C12. Each surfactant was investigated with respect to solubilization capacity for felodipine and haemolytic activity. The haemolytic activity was determined using a static method in which surfactant solutions were added to fresh dog blood. The polyoxyethylene-based surfactants were found to be more suitable as solubilizing agents than the sugar surfactants due to better solubilization capacities combined with lower haemolytic activities. The sugar surfactants caused severe haemolysis below or at the critical micelle concentration, in contrast to the polyoxyethylene-based surfactants that are nonhaemolytic in this concentration range. The structure-related variations in haemolytic activity are probably due to variations in the surfactants partition coefficients for the distribution equilibrium between the aqueous phase and the cell membrane. Longer alkyl chains cause higher haemolytic activity, while larger saccharide groups lower the activity. The clear difference between sugar and polyoxyethylene surfactants, which are considerably less haemolytic, is due to a combination of low critical micelle concentrations and presumably low degrees of partitioning of the latter surfactants into the cell membranes. [Copyright &y& Elsevier]

Abstract: Aims: To investigate the pharmacodynamics, pharmacokinetics and safety of the glucokinase activator AZD6370 after 1day of administration under fed and fasted conditions in patients with type 2 diabetes mellitus (T2DM). Methods: This was a two-part study. In Part A, patients received a single oral dose of AZD6370 (20, 60 or 180mg) or placebo in the fasted or fed states (both n =8). In Part B, patients (n =8) received placebo and a total dose of AZD6370 180mg given in one, two or four divided doses. Plasma glucose, insulin and C-peptide changes versus placebo were assessed. Results: AZD6370 provided dose-dependent reductions in plasma glucose of up to 30% versus placebo in both fasted and fed patients (p <0.001 at 60 and 180mg doses). Insulin secretion increased with dose, but absolute increases were relatively small in the fasted versus fed state (0–4h). Dosing AZD6370 twice or four-times over 1day gave a smoother 24-h glucose profile than single-dose. AZD6370 was rapidly absorbed. Pharmacokinetics of AZD6370 were dose-independent and unaffected by food. AZD6370 was generally well tolerated. Conclusions: AZD6370 produced dose-dependent glucose reductions and increased glucose-stimulated insulin secretion in patients with T2DM. [Copyright &y& Elsevier]

Background: Ximelagatran is an oral direct thrombin inhibitor for the prevention of thromboembolic disease. After oral administration, ximelagatran is rapidly absorbed and bioconverted to its active form, melagatran.Objective: To characterise the pharmacokinetics of melagatran in patients with nonvalvular atrial fibrillation (NVAF) receiving long-term treatment for prevention of stroke and systemic embolic events.Methods: A population pharmacokinetic model was developed based on data from three phase II studies (1177 plasma concentration observations in 167 patients, treated for up to 18 months) and confirmed by including data from two phase III studies (8702 plasma concentration observations in 3188 patients, treated for up to 24 months). The impact of individualised dosing on pharmacokinetic variability was evaluated by simulations of melagatran concentrations based on the pharmacokinetic model.Results: Melagatran pharmacokinetics were consistent across the studied doses and duration of treatment, and were described by a one-compartment model with first-order absorption and elimination. Clearance of melagatran was correlated to creatinine clearance, which was the most important predictor of melagatran exposure (explained 54% of interpatient variance in clearance). Total variability (coefficient of variation) in exposure was 45%; intraindividual variability in exposure was 23%. Concomitant medication with the most common long-term used drugs in the study population had no relevant influence on melagatran pharmacokinetics. Simulations suggested that dose adjustment based on renal function or trough plasma concentration had a minor effect on overall pharmacokinetic variability and the number of patients with high melagatran exposure.Conclusion: The pharmacokinetics of melagatran in NVAF patients were predictable, and consistent with results from previously studied patient populations. Dose individualisation was predicted to have a low impact on pharmacokinetic variability, supporting the use of a fixed-dose regimen of ximelagatran for long-term anticoagulant therapy in the majority of NVAF patients. [ABSTRACT FROM AUTHOR]

Background: Ximelagatran, an oral direct thrombin inhibitor, is currently in clinical development for the prevention and treatment of thromboembolic disease. Following oral administration, ximelagatran undergoes rapid bioconversion to its active form, melagatran, via two minor intermediates. Obesity, defined as body mass index (BMI) >30 kg/m[sup 2], is a recognised risk factor for thrombosis. There is potential for differences in the pharmacokinetics and pharmacodynamics of drugs administered to obese versus non-obese patients, and some drugs may require alternative administration strategies in obese patients. Objective: To investigate the effect of obesity on the pharmacokinetics and pharmacodynamics of melagatran after oral administration of ximelagatran. Design and participants: This was an open-label, single-dose, group-matched study in which obese subjects (BMI 32–39 kg/m[sup 2]; six male and six female; age 21–40 years) were matched by sex and age (±2 years) with non-obese subjects (BMI 21–26 kg/m[sup 2]; six male and six female; aged 21–39 years). Each subject received a single oral dose of ximelagatran 24mg. Blood samples for determination of plasma concentrations of melagatran and activated partial thromboplastin times (APTT; a marker of melagatran pharmacodynamics) were collected up to 12 hours after administration. Results: There were no statistically significant differences in the pharmacokinetic properties of melagatran between obese and non-obese subjects. Values of area under the melagatran plasma concentration-time curve, maximum plasma concentration (C[sub max]), time at which C[sub max] occurred and terminal elimination half-life were approximately 1 μmol · h/L, 0.2 μmol/L, 2 hours and 3 hours in both obese and non-obese subjects, respectively. In addition, there was no statistically significant difference between the obese and non-obese subjects in the amount of ximelagatran, melagatran or the minor intermediates ethyl-melagatran and melagatran hydroxyamidine excreted in urine. When relating the prolongation of APTT ratio to the square root of plasma concentration of melagatran and obesity status (no/yes), no statistically significant interaction between plasma concentration and obesity status was observed. Ximelagatran was well tolerated in both obese and non-obese subjects, and no bleeding events or serious adverse events occurred. Conclusion: No differences in the pharmacokinetics or pharmacodynamics of melagatran were detected between obese and non-obese subjects after oral administration of ximelagatran, suggesting that dose adjustment of ximelagatran in obesity (BMI up to 39 kg/m[sup 2]) is not necessary. [ABSTRACT FROM AUTHOR]

: ObjectivesThe effects of ximelagatran, an oral direct thrombin inhibitor (DTI), recombinant hirudin (r-hirudin) and enoxaparin on thrombin generation and platelet activation were studied in humans.: BackgroundRecombinant hirudin (parenteral DTI) and enoxaparin (low molecular weight heparin) have been demonstrated to be clinically effective in acute coronary syndromes. Ximelagatran is currently under investigation for the prevention and treatment of thromboembolism. The shed blood model allows for the study of thrombin generation and platelet activation in humans in vivo.: MethodsThis was an open-label, parallel-group study involving 120 healthy male volunteers randomized to receive one of three oral doses of ximelagatran (15, 30 or 60 mg), r-hirudin (intravenous) or enoxaparin (subcutaneous) at doses demonstrated to be clinically effective in acute coronary syndromes, or to serve as a control. Thrombin generation (prothrombin fragment 1+2 [F1+2] and thrombin-antithrombin complex [TAT]) and platelet activation (β-thromboglobulin [β-TG]) biomarkers were studied using a shed blood model involving blood collection from skin incisions made using standardized bleeding time devices.: ResultsOral ximelagatran, intravenous r-hirudin and subcutaneous enoxaparin rapidly and significantly (p < 0.05) decreased F1+2, TAT and β-TG levels in shed blood, indicating inhibition of thrombin generation and platelet activation. Statistically significant concentration (melagatran, the active form of ximelagatran)-response relationships for F1+2 (p = 0.005), TAT (p = 0.005) and β-TG (p < 0.001) levels, with IC50s of 0.376 (F1+2), 0.163 (TAT) and 0.115 (β-TG) μmol/l, were detected. Melagatran showed dose-proportional pharmacokinetics with low variability. All drugs were well tolerated.: ConclusionsOral administration of the DTI ximelagatran resulted in a rapid inhibition of both thrombin generation and platelet activation in a concentration-dependent manner using a human shed blood model. The inhibition of thrombin generation by 60 mg ximelagatran was comparable to that observed with doses of r-hirudin and enoxaparin demonstrated to be effective for the treatment of acute coronary syndromes. [Copyright &y& Elsevier]