Over-blending effect of lubricants on capsules manufacturing: a simple and fast wettability technique to predict batch dissolution performance.

Mixing/blending is a crucial operation in the manufacturing of solid drug products in the pharmaceutical industry. Although usually described and controlled in specific steps, blending is also inherent to other operations such as the transference of materials and equipment feeding systems. This study aimed to investigate a simple and fast wettability testing procedure capable to foresee the potential over-blending effects of lubricants occurring during the manufacturing of solid dosage forms. An industrial batch blend was submitted to two mixing mechanisms studies (diffusion and shear) during increasing time periods, and the developed wettability testing procedure was applied to assess their impact on blend water uptake. Capsules filled with these blends were tested for dissolution and disintegration. The method was applied to capsules with known dissolution results manufactured at an industrial scale. Results demonstrated that processes inducing shear stress led to less permeable blends with consequent retardation on capsules dissolution of at least 35% in the tested timepoints and obtained study metrics above 500 s. Moreover, disintegration testing was not able to detect non-compliant dissolutions, while the proposed wettability testing procedure proved to be able to identify performance failures. Wettability results correlate the effect of mixing mechanisms to capsules dissolution performance, evidencing that this technique can be applied in the pharmaceutical industry to evaluate possible over-blending effects.

Long-term efficacy of opicapone in fluctuating Parkinson's disease patients: a pooled analysis of data from two phase 3 clinical trials and their open-label extensions.

BACKGROUND AND PURPOSE: The aim was to evaluate the efficacy of the catechol-O-methyltransferase inhibitor opicapone (25 and 50 mg) as adjunct therapy to levodopa in a pooled population of Parkinson's disease patients who participated in the pivotal double-blind trials of opicapone and their 1-year open-label extensions. METHODS: Data (placebo, opicapone 25 mg and opicapone 50 mg) from the BIPARK-1 and BIPARK-2 double-blind and open-label studies were combined. The studies had similar designs, eligibility criteria and assessment methods. The primary efficacy variable in both double-blind studies was the change from baseline in absolute OFF time based on patient diaries. RESULTS: Double-blind treatment with opicapone (25 and 50 mg) significantly reduced absolute daily OFF time from a baseline of 6.1-6.6 h. The mean (and 95% confidence interval) treatment effect versus placebo was -35.1 (-62.1, -8.2) min (P = 0.0106) for the 25 mg dose and -58.1 (-84.5, -31.7) min (P < 0.0001) for the 50 mg dose. Reductions in OFF time were mirrored by significant increases in ON time without troublesome dyskinesia (P < 0.05 and P < 0.0001 for the 25 and 50 mg doses, respectively). No significant differences were observed for ON time with troublesome dyskinesia. Patient diary results from the open-label phase indicated a maintenance of effect for patients previously treated with opicapone 50 mg. The group previously treated with the 25 mg dose benefitted with further optimization of therapy during the open-label phase, whilst switching from placebo to opicapone led to significant reductions in OFF time and increased ON time. CONCLUSIONS: Over at least 1 year of open-label therapy, opicapone consistently reduced OFF time and increased ON time without increasing the frequency of troublesome dyskinesia.

Exposure-safety and efficacy response relationships and population pharmacokinetics of eslicarbazepine acetate.

OBJECTIVES: Eslicarbazepine acetate (ESL) is a once-daily (QD) oral antiepileptic drug (AED) for focal-onset seizures (FOS). Pharmacokinetic (PK) and pharmacodynamic (PD) models were developed to assess dose selection, identify significant AED drug interactions, and quantitate relationships between exposure and safety and efficacy outcomes from Phase 3 trials of adjunctive ESL. METHODS: Eslicarbazepine (the primary active metabolite of ESL) population PK was evaluated using data from 1351 subjects enrolled in 14 studies (11 Phase 1 and three Phase 3 studies) after multiple oral doses ranging from 400 to 1200 mg. Population PK and PD models related individual eslicarbazepine exposures to safety outcomes and efficacy responses. RESULTS: Eslicarbazepine PK was described by a one-compartment model with linear absorption and elimination. The probability of a treatment-emergent adverse event (TEAE; dizziness, headache, or somnolence) was higher with an initial dose of ESL 800 mg than with an initial dose of ESL 400 mg QD. Body weight, sex, region, and baseline use of carbamazepine (CBZ) or lamotrigine were also found to influence the probability of TEAEs. Eslicarbazepine exposure influenced serum sodium concentration, standardized seizure frequency, and probability of response; better efficacy outcomes were predicted in patients not from Western Europe (WE; vs WE patients) and those not taking CBZ (vs taking CBZ) at baseline. CONCLUSIONS: Pharmacokinetic and PK/PD modeling were implemented during the development of ESL for adjunctive treatment of FOS in adults. This quantitative approach supported decision-making during the development of ESL, and contributed to dosing recommendations and labeling information related to drug interactions.

Effects of adjunctive eslicarbazepine acetate on neurocognitive functioning in children with refractory focal-onset seizures.

PURPOSE: This was a phase-II, randomized, double-blind (DB), placebo-controlled study aimed to evaluate neurocognitive effects of eslicarbazepine acetate (ESL) as adjunctive therapy in pediatric patients with refractory focal-onset seizures (FOS). METHODS: Children (6-16years old) with FOS were randomized (2:1) to ESL or placebo. Treatment started at 10mg/kg/day, was up-titrated up to 30mg/kg/day (target dose), and maintained for 8weeks, followed by one-year open-label follow-up. The primary endpoint was change from baseline to the end of maintenance period in the composite Power of Attention assessed with the Cognitive Drug Research (CDR) system. Behavioral and emotional functioning and quality of life (QOL), secondary endpoints, were assessed with Child Health Questionnaire-Parent Form 50 (CHQ-PF50), Child Behavior Checklist (CBCL), and Raven's Standard Progressive Matrices (SPM). Efficacy was evaluated through changes in standardized seizure frequency (SF), responder rate, and proportion of seizure-free patients. Safety was evaluated by the incidence of treatment-emergent adverse events (TEAEs). RESULTS: One hundred and twenty-three patients were randomized. A noninferiority analysis failed to reject the null hypothesis that the change from baseline in the Power of Attention score in the ESL group was at least 121ms inferior to the placebo group for all age groups. The CDR scores showed no differences between placebo and ESL in Power of Attention (1868.0 vs 1759.5), Continuity of Attention (1.136 vs -1.786), Quality of Working Memory (-0.023 vs -0.024), and Speed of Memory (-263.4 vs -249.6). Nonsignificant differences between placebo and ESL were seen for CHQ-PF50, CBCL scores, and Raven's SPM. Episodic Memory Index showed significant negative effect on ESL. Efficacy results favored the ESL group (SF least square [LS] means 1.98 vs 4.29). The TEAEs had a similar incidence between treatment groups (41.0% vs 47.5%). CONCLUSIONS: Overall ESL did not produce statistically significant effects on neurocognitive and behavioral functioning in patients with epilepsy aged 6 to 16years. Additionally, ESL was effective in reducing seizure frequency and was well-tolerated.

Reliability of body-weight scalars on the assessment of propofol induction dose in obese patients.

BACKGROUND: Obese patients require specific perioperative care when compared with non-obese patients. The present study aimed to analyse the ability of size descriptors to estimate propofol induction dose in class II and III obese patients. METHODS: A cross-sectional study on adult patients with body mass index (BMI) equal to or greater than 35 kg/m2 and on adult patients with BMI lower than 35 kg/m2 was carried out. General anaesthesia was induced with remifentanil, propofol and rocuronium. Propofol infusion was started at 2000 mg/h until loss of consciousness. Bioelectrical impedance analysis and Brice modified interview was completed during pre- and post-operative evaluation, respectively. Measurements of propofol plasma concentration were performed using gas chromatography/ion trap-mass spectrometry. RESULTS: Forty patients were enrolled in the study. The median values of fat free mass (FFM) in BMI < 35 kg/m2 and BMI ≥ 35 kg/m2 groups were 70% and 55% of total body weight, respectively. Our results did not demonstrate a strong correlation level between the studied size descriptors and propofol induction dose in both groups. Nevertheless, when propofol doses were normalized by FFM, an apparent convergence of the empirical cumulative distribution functions was observed. CONCLUSION: None of the size descriptors was seen to be an effective predictor of the propofol induction dose in class II and III obese patients when a fixed infusion rate was used. Due to the observed variability between patients, guiding propofol induction dose against a clinical endpoint of unconsciousness appears more appropriate in order to avoid side effects related both with under or overdosing of propofol.

Distribution and pharmacokinetics of etamicastat and its N-acetylated metabolite (BIA 5-961) in dog and monkey.

1. The disposition etamicastat was evaluated in the Cynomolgus monkey after intravenous and oral administration of [(14)C]-etamicastat. The pharmacokinetics of etamicastat and its N-acetylated metabolite BIA 5-961 were also evaluated in monkeys and dogs. 2. In the monkey, 7 days after intravenous and oral administration of [(14)C]-etamicastat, 76.6-91.1% of the etamicastat-related radioactivity had been excreted mainly in urine. The radioactivity peaked in plasma between 4- and 8-h post-dosing followed by a quick decline and a slow terminal phase (half-life of 68.7 h). The calculated oral bioavailability for etamicastat was 46.1%. Etamicastat was quickly absorbed in monkeys and dogs with a half-life ranging from 5.2 to 9.9 h in monkeys and 6.9 to 11.4 h in dogs over. 3. The N-acetylated metabolite of etamicastat, represented 4-7% of the extent of exposure of etamicastat in the monkey, but was not found detectable in dogs. Gender did not influence etamicastat exposure and the concentration versus time curves fitted a dose-dependent pharmacokinetics in the dog, but not in the monkey. 4. In conclusion, etamicastat is rapidly absorbed and primarily excreted via urine in monkeys. Similarly, to humans, monkeys, unlike dogs, N-acetylate etamicastat and evidence that etamicastat pharmacokinetics is less than dose proportional.

Effect of opicapone on levodopa pharmacokinetics, catechol-O-methyltransferase activity and motor fluctuations in patients with Parkinson's disease.

BACKGROUND AND PURPOSE: Opicapone (OPC) is a novel third generation catechol-O-methyltransferase (COMT) inhibitor that enhances levodopa availability. This study investigated the effects of OPC in comparison with placebo on levodopa pharmacokinetics, tolerability and safety, COMT activity and motor response to levodopa in Parkinson's disease (PD) patients with motor fluctuations. METHODS: This was a randomized, multicentre, double-blind and placebo-controlled study in four parallel groups of PD patients treated with standard-release 100/25 mg levodopa/carbidopa or levodopa/benserazide and with motor fluctuations (wearing-OFF phenomenon). Subjects were sequentially assigned to be administered, once-daily, up to 28 days (maintenance phase), placebo (n = 10) or 5 (n = 10), 15 (n = 10) and 30 mg (n = 10) OPC. Two levodopa tests were performed, one at baseline and another following the maintenance phase. Subjects kept a diary to record motor fluctuations (ON/OFF periods) throughout the study. RESULTS: In relation to placebo, levodopa exposure (AUC0-6) increased 24.7%, 53.9% and 65.6% following 5, 15 and 30 mg OPC, respectively. Maximum COMT inhibition (Emax) ranged from 52% (5 mg OPC) to 80% (30 mg OPC). The study was not designed to detect any significant differences in motor performance, but the exploratory analysis performed shows improvement in various motor outcomes, including a dose-dependent change in absolute OFF time corresponding to a percentage decrease of 4.16% (P > 0.05), 29.55% (P > 0.05) and 32.71% (P < 0.05) with 5, 15 and 30 mg OPC, respectively. Treatments were generally well tolerated and safe. CONCLUSIONS: OPC is a promising new COMT inhibitor that significantly decreased COMT activity, increased systemic exposure to levodopa and improved motor response.

Pharmacological profile of opicapone, a third-generation nitrocatechol catechol-O-methyl transferase inhibitor, in the rat.

BACKGROUND AND PURPOSE: Catechol-O-methyltransferase (COMT) is an important target in the levodopa treatment of Parkinson's disease; however, the inhibitors available have problems, and not all patients benefit from their efficacy. Opicapone was developed to overcome those limitations. In this study, opicapone's pharmacological properties were evaluated as well as its potential cytotoxic effects. EXPERIMENTAL APPROACH: The pharmacodynamic effects of opicapone were explored by evaluating rat COMT activity and levodopa pharmacokinetics, in the periphery through microdialysis and in whole brain. The potential cytotoxicity risk of opicapone was explored in human hepatocytes by assessing cellular ATP content and mitochondrial membrane potential. KEY RESULTS: Opicapone inhibited rat peripheral COMT with ED50 values below 1.4 mg⋅kg(-1) up to 6 h post-administration. The effect was sustained over the first 8 h and by 24 h COMT had not returned to control values. A single administration of opicapone resulted in increased and sustained plasma levodopa levels with a concomitant reduction in 3-O-methyldopa from 2 h up to 24 h post-administration, while tolcapone produced significant effects only at 2 h post-administration. The effects of opicapone on brain catecholamines after levodopa administration were sustained up to 24 h post-administration. Opicapone was also the least potent compound in decreasing both the mitochondrial membrane potential and the ATP content in human primary hepatocytes after a 24 h incubation period. CONCLUSIONS AND IMPLICATIONS: Opicapone has a prolonged inhibitory effect on peripheral COMT, which extends the bioavailability of levodopa, without inducing toxicity. Thus, it exhibits some improved properties compared to the currently available COMT inhibitors.

Brain and peripheral pharmacokinetics of levodopa in the cynomolgus monkey following administration of opicapone, a third generation nitrocatechol COMT inhibitor.

OBJECTIVE: The present study aimed at evaluating the effect of opicapone, a third generation nitrocatechol catechol-O-methyltransferase (COMT) inhibitor, on the systemic and central bioavailability of 3,4-dihydroxy-l-phenylalanine (levodopa) and related metabolites in the cynomolgus monkey. METHODS: Four monkeys, implanted with guiding cannulas for microdialysis probes, in the substantia nigra, dorsal striatum and prefrontal cortex, were randomized in two groups that received, in a crossover design, vehicle or 100 mg/kg opicapone for 14 days. Twenty-three hours after last administration of vehicle or opicapone, animals were challenged with levodopa/benserazide (12/3 mg/kg). Extracellular dialysate and blood samples were collected over 360 min (at 30 min intervals) for the assays of catecholamine and COMT activity. RESULTS: Opicapone increased levodopa systemic exposure by 2-fold not changing Cmax values and reduced both 3-O-methyldopa (3-OMD) exposure and Cmax values by 5-fold. These changes were accompanied by ∼76-84% reduction in erythrocyte COMT activity. In dorsal striatum and substantia nigra, opicapone increased levodopa exposure by 1.7- and 1.4-fold, respectively, reducing 3-OMD exposure by 5- and 7-fold respectively. DOPAC exposure was increased by 4-fold in the substantia nigra. In the prefrontal cortex, opicapone increased levodopa exposure and reduced 3-OMD levels by 2.3- and 2.4-fold, respectively. CONCLUSIONS: Opicapone behaved as long-acting COMT inhibitor that markedly increased systemic and central levodopa bioavailability. Opicapone is a strong candidate to fill the unmet need for COMT inhibitors that lead to more sustained levodopa levels in Parkinson's disease patients.

Development and validation of an enantioselective liquid-chromatography/tandem mass spectrometry method for the separation and quantification of eslicarbazepine acetate, eslicarbazepine, R-licarbazepine and oxcarbazepine in human plasma.

The purpose of this study was develop and validate a sensitive and specific enantioselective liquid-chromatography/tandem mass spectrometry (LC-MS/MS) method, for the simultaneous quantification of eslicarbazepine acetate (ESL), eslicarbazepine (S-Lic), oxcarbazepine (OXC) and R-licarbazepine (R-Lic) in human plasma. Analytes were extracted from human plasma using solid phase extraction and the chromatographic separation was achieved using a mobile phase of 80% n-hexane and 20% ethanol/isopropyl alcohol (66.7/33.3, v/v). A Daicel CHIRALCEL OD-H column (5 µm, 50 mm × 4.6 mm) was used with a flow rate of 0.8 mL/min, and a run time of 8 min. ESL, S-Lic, R-Lic, OXC and the internal standard, 10,11-dihydrocarbamazepine, were quantified by positive ion electrospray ionization mass spectrometry. The method was fully validated, demonstrating acceptable accuracy, precision, linearity, and specificity in accordance with FDA regulations for the validation of bioanalytical methods. Linearity was proven over the range of 50.0-1000.0 ng/mL for ESL and OXC and over the range of 50.0-25,000.0 ng/mL for S-Lic and R-Lic. The intra- and inter-day coefficient of variation in plasma was less than 9.7% for ESL, 6.0% for OXC, 7.7% for S-Lic and less than 12.6% for R-Lic. The accuracy was between 98.7% and 107.2% for all the compounds quantified. The lower limit of quantification (LLOQ) was 50.0ng/mL for ESL, S-Lic, OXC and R-Lic in human plasma. The short-term stability in plasma, freeze-thaw stability in plasma, frozen long-term stability in plasma, autosampler stability and stock solution stability all met acceptance criteria. The human plasma samples, collected from 8 volunteers, showed that this method can be used for therapeutic monitoring of ESL and its metabolites in humans treated with ESL.

Pharmacokinetics of eslicarbazepine acetate at steady-state in adults with partial-onset seizures.

OBJECTIVE: To evaluate the pharmacokinetics of eslicarbazepine acetate (ESL) at steady-state in adults with partial-onset seizures who have taken ESL for at least 1 year with one or two concomitant antiepileptic drugs (AEDs). METHODS: Blood samples for the pharmacokinetic assessment were taken at pre-dose, and 1, 2, 3, 4, 6, 8, 12 and 24h post-dose at steady-state in 51 patients stabilised on chronic (beyond 1 year) treatment with ESL 400mg (n=7), 800mg (n=26) or 1200mg (n=18) once-daily. Most patients (n=29, 56.9%) were receiving 2 concomitant AEDs, and most frequent co-medications were carbamazepine (n=34, 66.7%) and valproic acid (n=19, 37.3%). Plasma concentrations of ESL and its metabolites eslicarbazepine, R-licarbazepine and oxcarbazepine (OXC) were determined by a validated chiral method using liquid chromatography coupled to mass spectrometry. RESULTS: Similarly to earlier findings in healthy subjects, plasma ESL concentrations were consistently below the lower limit of quantification (50ng/mL). The major compound in plasma was the active metabolite eslicarbazepine, which reached maximum concentrations (C(max)) 2h post-dose; thereafter, its plasma concentrations declined with a mean apparent half-life of 13, 14, and 20h in patients receiving ESL doses of 400, 800, and 1200mg once daily, respectively. Eslicarbazepine C(max) were 9.7, 15.5 and 23.0µg/mL, and areas under the plasma concentration-time curve over the dosing interval (AUC(0-24)) were 132.5, 205.4 and 336.1µgh/mL in patients receiving ESL doses of 400, 800 and 1200mg once-daily, respectively. Eslicarbazepine main pharmacokinetic parameters (C(max) and AUC(0-24)) were dose-proportional. R-licarbazepine and OXC were minor metabolites. CONCLUSIONS: Following once-daily oral administration of ESL 400mg, 800mg and 1200mg to epilepsy patients treated concomitantly with one or two other AEDs, ESL was rapidly converted to eslicarbazepine, which was the primary active compound found in plasma. Systemic exposure to eslicarbazepine was dose-proportional.

Long-term regulation of Na+,K+-ATPase in opossum kidney cells by ouabain.

Na(+),K(+)-ATPase, a basolateral transporter responsible for tubular reabsorption of Na(+) and for providing the driving force for vectorial transport of various solutes and ions, can also act as a signal transducer in response to the interaction with steroid hormones. At nanomolar concentrations ouabain binding to Na(+),K(+)-ATPase activates a signaling cascade that ultimately regulates several membrane transporters including Na(+),K(+)-ATPase. The present study evaluated the long-term effect of ouabain on Na(+),K(+)-ATPase activity (Na(+) transepithelial flux) and expression in opossum kidney (OK) cells with low (40) and high (80) number of passages in culture, which are known to overexpress Na(+),K(+)-ATPase (Silva et al., 2006, J Membr Biol 212, 163-175). Activation of a signal cascade was evaluated by quantification of ERK1/2 phosphorylation by Western blot. Na(+),K(+)-ATPase activity was determined by electrophysiological techniques and expression by Western blot. Incubation of cells with ouabain induced activation of ERK1/2. Long-term incubation with ouabain induced an increase in Na(+) transepithelial flux and Na(+),K(+)-ATPase expression only in OK cells with 80 passages in culture. This increase was prevented by incubation with inhibitors of MEK1/2 and PI-3K. In conclusion, ouabain-activated signaling cascade mediated by both MEK1/2 and PI-3K is responsible for long-term regulation of Na(+) transepithelial flux in epithelial renal cells. OK cell line with high number of passages is suggested to constitute a particular useful model for the understanding of ouabain-mediated regulation of Na(+) transport.

Age-dependent effect of ouabain on renal Na+,K+-ATPase.

AIMS: This study examines the effect of chronic ouabain-treatment on renal Na(+) handling in 12-week and 52-week old rats. MAIN METHODS: Wistar Kyoto rats aged 5 weeks or 45 weeks were treated with ouabain or vehicle during 7 weeks. Blood pressure was measured in conscious animals throughout the study. After 7 weeks of treatment urinary electrolyte concentration, Na(+),K(+)-ATPase activity and α(1)-subunit expression were determined in 12-week and 52-week old rats. KEY FINDINGS: In 12-week and 52-week old rats ouabain produced a significant increase in systolic blood pressure. Although no differences were observed in Na(+) excretion in these animals, 12-week old ouabain-treated rats had lower Na(+),K(+)-ATPase activity in proximal tubules. However, 12-week old ouabain-treated rats had decreased fractional excretion of Na(+). In proximal tubules of 52-week old rats Na(+),K(+)-ATPase activity did not differ between vehicle and ouabain-treated groups. SIGNIFICANCE: Our results show that in Wistar Kyoto rats renal response to ouabain treatment may be age-dependent and that the hypertensive effect of ouabain is independent of the effect on renal Na(+),K(+)-ATPase.

Renal aging in WKY rats: changes in Na+,K+ -ATPase function and oxidative stress.

It has been suggested that alterations in Na(+),K(+)-ATPase mediate the development of several aging-related pathologies, such as hypertension and diabetes. Thus, we evaluated Na(+),K(+)-ATPase function and H(2)O(2) production in the renal cortex and medulla of Wistar Kyoto (WKY) rats at 13, 52 and 91 weeks of age. Creatinine clearance, proteinuria, urinary excretion of Na(+) and K(+) and fractional excretion of Na(+) were also determined. The results show that at 91 weeks old WKY rats had increased creatinine clearance and did not have proteinuria. Despite aging having had no effect on urinary Na(+) excretion, urinary K(+) excretion was increased and fractional Na(+) excretion was decreased with age. In renal proximal tubules and isolated renal cortical cells, 91 week old rats had decreased Na(+),K(+)-ATPase activity when compared to 13 and 52 week old rats. In renal medulla, 91 week old rats had increased Na(+),K(+)-ATPase activity, paralleled by an increase in protein expression of α(1)-subunit of Na(+),K(+)-ATPase. In addition, renal H(2)O(2) production increased with age and at 91 weeks of age renal medulla H(2)O(2) production was significantly higher than renal cortex production. The present work demonstrates that although at 91 weeks of age WKY rats were able to maintain Na(+) homeostasis, aging was accompanied by alterations in renal Na(+),K(+)-ATPase function. The observed increase in oxidative stress may account, in part, for the observed changes. Possibly, altered Na(+),K(+)-ATPase renal function may precede the development of age-related pathologies and loss of renal function.

Increased responsiveness to JNK1/2 mediates the enhanced H2O2-induced stimulation of Cl-/HCO3- exchanger activity in immortalized renal proximal tubular epithelial cells from the SHR.

We have previously demonstrated that exogenous H2O2 stimulates Cl(-)/HCO3(-) exchanger activity in immortalized renal proximal tubular epithelial (PTE) cells from both the Wistar-Kyoto (WKY) rat and the spontaneously hypertensive rat (SHR), this effect being more pronounced in SHR cells. The aim of the present study was to examine the mechanism of H2O2-induced stimulation of Cl(-)/HCO3(-) exchanger activity in WKY and SHR cells. It is now reported that the SHR PTE cells were endowed with an enhanced capacity to produce H2O2, comparatively with WKY cells and this was accompanied by a decreased expression of SOD2, SOD3, and catalase in SHR PTE cells. The stimulatory effect of H2O2 on the exchanger activity was blocked by SP600125 (JNK inhibitor), but not by U0126 (MEK1/2 inhibitor) or SB203580 (p38 inhibitor) in both cell lines. Basal JNK1 and JNK2 protein expression was higher in SHR PTE cells than in WKY PTE cells. H2O2 had no effect on p-JNK1/2 in WKY PTE cells over time. By contrast, H2O2 treatment resulted in a rapid and sustained increase in JNK1/2 phosphorylation in SHR PTE cells, which was completely abolished by apocynin. Treatment of SHR PTE cells with apocynin significantly decreased the H2O2-induced stimulation of Cl(-)/HCO3(-) exchanger activity. It is concluded that H2O2-induced stimulation of Cl(-)/HCO3(-) exchanger activity is regulated by JNK1/2, particularly by JNK2, in SHR PTE cells. The imbalance between oxidant and antioxidant mechanisms in SHR PTE cells enhances the response of JNK1/2 to H2O2, which contributes to their increased sensitivity to H2O2.

Eslicarbazepine acetate as adjunctive therapy in adult patients with partial epilepsy.

OBJECTIVE: To investigate the efficacy and safety of once-daily eslicarbazepine acetate (ESL) when used as add-on treatment in adults with > or = 4 partial-onset seizures per 4-week despite treatment with 1 to 3 antiepileptic drugs (AEDs). METHODS: This double-blind, parallel-group, multicenter study consisted of an 8-week observational baseline period, after which patients were randomized to placebo (n=100) or once-daily ESL 400 mg (n=96), 800 mg (n=101), or 1200 mg (n=98). Patients then entered a 14-week double-blind treatment phase. All patients started on their full maintenance dose except for those in the ESL 1200 mg group who received once-daily ESL 800 mg for 2 weeks before reaching their full maintenance dose. RESULTS: Seizure frequency per 4-week (primary endpoint) over the 14-week double-blind treatment period was significantly lower than placebo in the ESL 800 mg and 1200 mg (p<0.001) groups. Responder rate (> or = 50% reduction in seizure frequency) was 13.0% (placebo), 16.7% (400 mg), 40.0% (800 mg, p<0.001), and 37.1% (1200 mg, p<0.001). Median relative reduction in seizure frequency was 0.8% (placebo), 18.7% (400 mg), 32.6% (800 mg, p<0.001), and 32.8% (1200 mg). Discontinuation rates due to adverse events (AEs) were 3.0% (placebo), 12.5% (400 mg), 18.8% (800 mg), and 26.5% (1200 mg). The most common (>5%) AEs in any group were dizziness, somnolence, headache, nausea, diplopia, abnormal coordination, vomiting, blurred vision, and fatigue. The majority of AEs were of mild or moderate severity. CONCLUSIONS: Treatment with once-daily eslicarbazepine acetate 800 mg and 1200 mg was more effective than placebo and generally well tolerated in patients with partial-onset seizures refractory to treatment with 1 to 3 concomitant AEDs.

Pharmacokinetic interaction study between eslicarbazepine acetate and lamotrigine in healthy subjects.

OBJECTIVE: Anti-epileptic drugs are often used in combination. Both eslicarbazepine (main metabolite of eslicarbazepine acetate, ESL) and lamotrigine undergo conjugation with glucuronic acid, and both eslicarbazepine and its glucuronide and lamotrigine glucuronide undergo extensive renal elimination; therefore, there is a potential for interaction. This study investigated the interaction between ESL and lamotrigine in healthy subjects. METHODS: Open-label study in two parallel groups of 16 healthy volunteers each. After an 8-day treatment with ESL or lamotrigine, ESL (1200 mg once-daily) and lamotrigine (150 mg once-daily) were co-administered for 19 days. Geometric mean ratios (GMR) and 90% confidence intervals (90% CI) for maximum plasma concentration (C(max)) and area under the plasma concentration-time curve in the dosing interval (AUC(0-24)) were calculated for eslicarbazepine (ESL active metabolite) and lamotrigine. RESULTS: The C(max) and AUC(0-24) GMR (90% CI) were, respectively, 95% (87-102%) and 96% (91-102%) for eslicarbazepine, and 88% (82-94%) and 86% (81-92%) for lamotrigine. The 90% CI of the C(max) and AUC(0-24) GMR fell within the prespecified acceptance interval (80-125%) both for eslicarbazepine and lamotrigine. CONCLUSION: There was no significant pharmacokinetic interaction between ESL and lamotrigine in healthy subjects. Therefore, no dosage adjustment appears to be usually required in either lamotrigine or ESL when the drugs are co-administered.

Efficacy and safety of 800 and 1200 mg eslicarbazepine acetate as adjunctive treatment in adults with refractory partial-onset seizures.

OBJECTIVES: To evaluate the efficacy and safety of eslicarbazepine acetate (ESL) as adjunctive therapy in adults with partial-onset seizures. MATERIAL AND METHODS: Double-blind, placebo-controlled, parallel-group, multicenter study consisting of an 8-week baseline period, after which patients were randomized to placebo (n = 87) or once-daily ESL 800 mg (n = 85) or 1200 mg (n = 80). Patients received half dose during 2 weeks preceding a 12-week maintenance period. RESULTS: Seizure frequency over the maintenance period was significantly (P < 0.05) lower than placebo in both ESL groups. Responder rate was 23% (placebo), 35% (800 mg), and 38% (1200 mg). Median relative reduction in seizure frequency was 17% (placebo), 38% (800 mg), and 42% (1200 mg). The most common adverse events (AEs) (>10%) were dizziness, somnolence, headache, and nausea. The majority of AEs were of mild or moderate severity. CONCLUSIONS: Once-daily treatment with ESL 800 and 1200 mg was effective and generally well tolerated.

Effect of eslicarbazepine acetate on the pharmacokinetics of metformin in healthy subjects.

PURPOSE: Eslicarbazepine acetate (ESL) is a new voltage-gated sodium channel blocker currently in development for the treatment of neuropathic pain, including that of diabetic origin. The primary objective was to investigate the effect of ESL on the pharmacokinetics of metformin, a commonly used oral antidiabetic drug. METHODS: Randomized, open-label, two-way crossover study in 20 healthy subjects. The volunteers received an 850 mg single-dose of metformin hydrochloride on two occasions - once as such and once after pre-treatment with an oral once-daily dose of ESL 1200 mg for 6 days - separated by a washout period of at least 2 weeks. The bioequivalence approach was used for assessing the effect of ESL on the pharmacokinetics of metformin. Test/Reference geometric mean ratios (GMR) and 90% confidence intervals (90% CI) were calculated for AUC0- yen, AUC0-12 and Cmax of metformin. RESULTS: Test/Reference metformin GMR (90% CI) was 0.95 (0.86; 1.05) for AUC0- yen, 0.95 (0.88; 1.06) for AUC0-12, and 0.88 (0.77; 1.00) for Cmax. Formal bioequivalence could not be demonstrated for metformin Cmax. However, the extent of exposure to metformin, as reflected by AUC0-12 and AUC0- yen, allows the claim of bioequivalence since the 90% CI of the GMR fall within the pre-specified bioequivalence acceptance interval (0.80; 1.25). CONCLUSION: Once-daily administration of ESL 1,200 mg had no relevant effect on the systemic exposure to metformin pharmacokinetics in healthy subjects.

Effect of food on the pharmacokinetic profile of trans-resveratrol.

OBJECTIVE: It has been postulated that trans-resveratrol may act as an antioxidant, cardioprotective, neuroprotective and cancer chemopreventive agent. The objective of this study was to investigate the effect of food on the bioavailability of trans-resveratrol following oral administration. MATERIAL AND METHODS: Single-centre, open-label, randomized, 2-way crossover study on 24 healthy subjects. The study consisted of two consecutive treatment periods separated by a washout of 7 days or more. On each of the study periods subjects were administered a single-dose of 400 mg of trans-resveratrol following either a standard high fat content meal or 8 hs of fasting. RESULTS: There was a large interindividual variability in the trans-resveratrol pharmacokinetic parameters. Mean +/- SD maximum plasma concentration (Cmax) was 42.2 +/- 36.6 ng/ml in fed and 47.3 +/- 30.0 ng/ml in fasting conditions. Median time to Cmax (tmax) was 2.0 h in fed and 0.5 h in fasting (p < 0.0001). The fed/fasting geometric mean ratio (GMR) and 90% confidence interval (90% CI) were 79.4 and 53.8, 117.0% for Cmax, and 106.0 and 86.8, 128.0% for the area under the plasma concentration-time curve (AUC0- yen). The 90% CI for the GMR of AUC0- yen and Cmax fall outside the usual bioequivalence acceptance range of 80, 125%, but that of AUC0- yen was close to the bioequivalence standard. CONCLUSION: The rate of absorption of trans-resveratrol following an oral 400 mg single-dose was significantly delayed by the presence of food, as reflected by Cmax and tmax. However, the extent of absorption, as reflected by AUC- yen, was not affected in a relevant way.