Investigations on dose proportionality and drug-drug interaction for a fixed-dose combination of trazodone and gabapentin.

OBJECTIVES: To establish dose proportionality for trazodone and gabapentin at fixed ratios of trazodone/gabapentin 2.5/25, 10/100, and 30/300 and investigation of potential drug-drug interaction at a dose of 10/100. MATERIALS AND METHODS: 29 out of 30 healthy subjects completed this single-center, open-label, randomized, 5-period cross-over trial with single-dose fasted administrations. Administrations were separated by a washout period of at least 6 days. Blood samples were drawn until 48 hours post dose. A validated liquid chromatography-tandem mass spectrometry method (LC-MS/MS) was applied for determination of trazodone and gabapentin in plasma. The lower limits of quantitation (LLOQ) were 1.00 ng/mL and 5.00 ng/mL for trazodone and gabapentin, respectively. Adverse events (AEs) were analyzed in the study population descriptively. RESULTS: Plasma concentrations were characterized thoroughly. For trazodone, assessment of proportionality (power model/pairwise-comparison by ANOVA) showed proportionality for AUC over all doses and for Cmax between the middle and high dose. For gabapentin, a less than proportional increase in both metrices was present with a likely proportional increase from 25 to 100 mg only. Considering common bioequivalence criteria, absence of pharmacokinetic interaction was confirmed comparing the combination and individual agents. 23 subjects experienced 53 AEs during the trial, the most frequent being fatigue (20 cases/15 subjects) and dizziness (14 cases/11 subjects). No serious AEs were reported. CONCLUSION: To our knowledge, for the first time, proportionality for trazodone at doses of 2.5 to 30 mg and for gabapentin at doses of 25 to 300 mg was investigated. Absence of a pharmacokinetic interaction was shown.

A novel rizatriptan oral gel formulation: Bioavailability and bioequivalence.

OBJECTIVES: To establish the relative bioavailability between a newly developed oral gel and a marketed oral lyophilisate-containing rizatriptan benzoate. MATERIALS AND METHODS: A total of 47 out of 48 healthy subjects, aged 34 ± 10 (SD) years and body mass index 24.7 ± 3.3 (SD) kg/m2 completed this single-center, open-label, randomized, 2-period cross-over trial with single-dose fasted administrations. Intake of both investigational products was separated by a washout period of at least 6 days. For pharmacokinetic evaluation, blood samples were withdrawn until 24 hours post dose. A validated liquid chromatography-tandem mass spectrometry method (LC-MS/MS) was applied for the determination of rizatriptan in plasma. The lower limit of quantitation (LLOQ) was 0.100 ng/mL. Adverse events (AEs) were descriptively analyzed in the study population. Palatability of the new product was investigated based on a questionnaire. RESULTS: The geometric means of the parameters related with the extent of total exposure, i.e., AUC0-tlast and AUC0-∞, were 60.285 ng × h/mL and 60.865 ng × h/mL for test and 62.729 ng × h/mL and 63.312 ng × h/mL for reference, respectively. The geometric means of the peak exposure, i.e., Cmax, were 21.262 ng/mL for test and 21.447 ng/mL for reference. The point estimates (PEs) of the test/reference (T/R) adjusted geometric mean ratios of AUC0-tlast, Cmax, and AUC0-∞ (secondary parameter) were 96.11%, 99.12%, and 96.15%, respectively, and all of them showed 90% confidence intervals (CIs) within the range of 80.00 - 125.00% as suggested by regulatory requirements for bioequivalence assessment. In total, 13 subjects experienced 20 AEs during the trial; the most frequently reported AEs were headache (5 cases) and dizziness (3 cases). No AEs of severe intensity were reported. Palatability assessment of the new product provided sufficient data to discuss its acceptability. CONCLUSION: Bioequivalence was demonstrated in terms of rate and extent of absorption after administration of test and reference products. Concerning the safety evaluation, no negative implications on the possible use of the test formulation could be determined. Based on ratings by the subjects no relevant problem concerning acceptability of the new formulation in particular regarding taste and smell is to be expected.

Safety and tolerability of a novel oral nutritional supplement in healthy volunteers.

BACKGROUND AND OBJECTIVE: Foods for Special Medical Purposes (FSMPs) are formulated to support the nutritional needs of subjects with impaired capacity to ingest, digest or absorb ordinary food or nutrients. Polglumyt® is a proprietary highly purified, high quality glycogen obtained from mussels. Here we report the results of a single-center, single dose, open label, single arm study carried out to investigate acceptance (i.e. gastrointestinal tolerance and palatability), metabolic profile and safety of a low osmolarity, high-density energy Polglumyt®-based drink (the investigational product, IP) as a novel FSMP. METHODS: Twelve healthy subjects received a single oral administration of the IP under fasting conditions. The study endpoints were: changes in gastrointestinal system tolerability at 3 h, 6 h and 24 h after IP intake; IP palatability evaluation; metabolic evaluation through the kinetic profile of circulating glucose, insulin and C-peptide from 0 h to 6 h after IP intake and changes from baseline in circulating triglycerides at 3 h and 6 h after IP intake. RESULTS: The IP showed a good gastrointestinal tolerability and an acceptable palatability. The IP did not affect the physiological glycemic profile and the triglycerides levels 6 h after the intake. The IP was well tolerated by study subjects, with no or minor adverse events. CONCLUSIONS: The study results encourage additional clinical investigations on the IP as a novel FSMP in patients with impaired digestion or gastrointestinal absorption, unable to assume an ordinary diet, e.g. patients undergoing invasive gastrointestinal surgery, elderly or oncological patients, even with certain metabolic disorders.

Effect of 3 Single Doses of Trazodone on QTc Interval in Healthy Subjects.

This study evaluated the effect of 3 doses of a trazodone hydrochloride 6% oral drops solution on the QT interval of healthy volunteers. Subjects were randomly assigned to receive a single dose of trazodone 20 mg, 60 mg, and 140 mg, moxifloxacin 400 mg, and trazodone-matched placebo in 5 periods separated by 7-day washouts, according to a double-blind, crossover study design. Subjects were monitored continuously, and triplicate ECGs were extracted from baseline (predose) until 24 hours postdose. Blood samples for trazodone and moxifloxacin analyses were collected at the same time points. The concentration-QTc relationship assessed on placebo-adjusted change from baseline for Fridericia-corrected QT (ΔΔQTcF) was the primary end point. ΔΔQTcF values of 4.5, 12.3, and 19.8 ms for the 20-, 60-, and 140-mg doses were observed at the corresponding trazodone peak plasma concentrations. The upper bound of the 90%CI exceeded 10 ms for the 60- and the 140-mg doses. Time-matched analysis results were in line with these findings. No significant trazodone effect on heart rate or PR or QRS intervals and no clinically significant new morphological changes were present. In this moxifloxacin-validated ECG trial, trazodone had a modest, dose-dependent effect on cardiac repolarization, with no QTc prolongation observed with the 20-mg dose and an effect exceeding the values set in E14 guideline with the 60- and 140-mg doses. The effect on cardiac repolarization is unlikely to represent a clinical risk for ventricular proarrhythmia, but caution should be used with concomitant use of other medications that prolong QT or increase trazodone exposure.

Estimation of an Appropriate Dose of Trazodone for Pediatric Insomnia and the Potential for a Trazodone-Atomoxetine Interaction.

There is a paucity of clinical trials for the treatment of pediatric insomnia. This study was designed to predict the doses of trazodone to guide dosing in a clinical trial for pediatric insomnia using physiologically-based pharmacokinetic (PBPK) modeling. Data on the pharmacokinetics of trazodone in children are currently lacking. The interaction potential between trazodone and atomoxetine was also predicted. Doses predicted in the following age groups, with exposures corresponding to adult dosages of 30, 75, and 150 mg once a day (q.d.), respectively, were: (i) 2- to 6-year-old group, doses of 0.35, 0.8, and 1.6 mg/kg q.d.; (ii) >6- to 12-year-old group, doses of 0.4, 1.0, and 1.9 mg/kg q.d.; (iii) >12- to 17-year-old group, doses of 0.4, 1.1, and 2.1 mg/kg q.d. An interaction between trazodone and atomoxetine was predicted to be unlikely. Clinical trials based on the aforementioned predicted dosing are currently in progress, and pharmacokinetic data obtained will enable further refinement of the PBPK models.

Optimization of Indazole-Based GSK-3 Inhibitors with Mitigated hERG Issue and In Vivo Activity in a Mood Disorder Model.

Bipolar disorders still represent a global unmet medical need and pose a requirement for novel effective treatments. In this respect, glycogen synthase kinase 3ß (GSK-3ß) aberrant activity has been linked to the pathophysiology of several disease conditions, including mood disorders. Therefore, the development of GSK-3ß inhibitors with good in vivo efficacy and safety profile associated with high brain exposure is required. Accordingly, we have previously reported the selective indazole-based GSK-3 inhibitor 1, which showed excellent efficacy in a mouse model of mania. Despite the favorable preclinical profile, analog 1 suffered from activity at the hERG ion channel, which prevented its further progression. Herein, we describe our strategy to improve this off-target liability through modulation of physicochemical properties, such as lipophilicity and basicity. These efforts led to the potent inhibitor 14, which possessed reduced hERG affinity, promising in vitro ADME properties, and was very effective in a mood stabilizer in vivo model.

Penetration of orally administered prulifloxacin into human prostate tissue.

BACKGROUND AND OBJECTIVE: Prulifloxacin, a fluoroquinolone antibacterial agent, may be a useful addition to the antimicrobial armamentarium against prostatitis once the ability of its active metabolite, ulifloxacin, to penetrate prostatic tissue has been determined. This study set out to evaluate ulifloxacin penetration into the prostate following administration of the oral fluoroquinolone prodrug prulifloxacin in patients undergoing transurethral resection of the prostate (TURP). METHODS: This was a phase I, randomized, open-label, single-centre study involving 20 male Caucasian patients (mean age 63.1 years) requiring TURP for treatment of benign prostatic hyperplasia. Sixteen patients were randomized to receive prulifloxacin; the other four patients were not treated (controls) in order to validate the bioanalytical method. Patients in the active treatment groups were randomized to receive one or three once-daily doses of prulifloxacin 600 mg, with the last administration 3 hours prior to surgery. Central/transitional and peripheral zone prostatic tissue samples were obtained from the 6 o'clock and 9 o'clock positions in the prostate, and blood samples were collected concurrently. Ulifloxacin concentrations were determined in the tissue samples and plasma using liquid chromatography-tandem mass spectrometry. Safety was also assessed. RESULTS: Prostatic tissue concentrations of ulifloxacin always exceeded those in plasma. Mean ulifloxacin concentrations measured in samples collected from the 6 o'clock central/transitional zone of the prostate were higher in patients who received prulifloxacin for 3 days than in those who received a single dose. Mean prostatic tissue/plasma ulifloxacin concentration ratios after single and repeated prulifloxacin administration ranged from 3.8 to 7.1 and from 3.9 to 9.5, respectively. The highest mean ratio was found in the 6 o'clock central/transitional zone after repeated dosing. Prostatic levels of ulifloxacin were above the minimum inhibitory concentrations for the most common causative pathogens of bacterial prostatitis. No treatment-related toxicities were reported. CONCLUSION: These findings confirm the ability of prulifloxacin to penetrate prostatic tissues, indicating high exposure of the target tissue to ulifloxacin and, therefore, a potential therapeutic role for prulifloxacin in the treatment of bacterial prostatic infections.

Juvenile rat and pediatric trazodone studies: how to gain extra sensitivity to overcome bioanalytical challenges.

AIM: Trazodone (TZD) is used for the treatment of depression in adults and, off-label, as a sleep medication in adult and pediatric populations. The off-label use is well documented, however further clinical studies are needed to confirm its efficacy and safety for the treatment of sleep disorders. In this scenario, we developed a bioanalytical method to quantify low TZD concentrations in samples collected by capillary microsampling (CMS) to support dose finding, Good Laboratory Practice juvenile rat toxicokinetic and upcoming pediatric studies. METHODOLOGY: A method using only 8 µl of plasma was developed and successfully used for analyzing CMS samples from juvenile rats throughout toxicokinetic study. CONCLUSION: By harmoniously maximizing each analytical step, we achieved a sensitive method to quantify TZD in CMS samples.

New Insights on the Pharmacokinetics of Ulifloxacin After Administration of Prulifloxacin in Patients with Mild, Moderate and Severe Renal Impairment.

BACKGROUND: The antibacterial agent prulifloxacin, a prodrug of ulifloxacin, is indicated in the treatment of acute lower urinary tract infections, acute exacerbation of chronic bronchitis and acute bacterial rhinosinusitis. OBJECTIVE: We aimed to provide new insights on the pharmacokinetics (PK) of ulifloxacin in patients with different degrees of renal impairment. METHODS: A two-site, international, open-label, parallel-group, single- and repeated-dose study was performed. The drug was administered as a single dose of 600 mg to subjects with normal renal function and patients with mild, moderate and severe renal impairment. Subsequently, the same dose was administered daily for 7 days to subjects with normal renal function and patients with mild and moderate renal impairment, while a dose of 300 mg was administered daily for 7 days to patients with severe renal impairment. Plasma and urine ulifloxacin levels were measured. Complete safety evaluation was performed. RESULTS: Exposure to ulifloxacin increased as renal function decreased due to a lower ulifloxacin clearance. Ulifloxacin PK were significantly changed only in patients with severe renal impairment. The amount of ulifloxacin excreted in urine over a 24-h dosing period was similar in subjects with normal renal function and patients with mild impaired renal function, but lower in those with moderate and severe renal impairment. CONCLUSION: Our data show that prulifloxacin is a safe quinolone and is well tolerated in both subjects with normal renal function and patients with impaired renal function, requiring a minimal dosage adjustment only in patients with severe renal impairment.

Penetration of prulifloxacin into gynaecological tissues after single and repeated oral administrations.

OBJECTIVE: This study aimed to evaluate the penetration into gynaecological tissues of ulifloxacin, the active metabolite of prulifloxacin, a once-daily fluoroquinolone administered once or in repeated doses. METHODS: This was an open-label, randomised study that included 20 consenting female inpatients (age range 40-65 years) requiring total simple hysterectomy as a result of benign disease. Three groups of patients were enrolled: group A (four patients whose gynaecological tissue samples were used to set up the bioanalytical method); group B (eight patients treated 3 hours before surgery with one 600 mg tablet of prulifloxacin); group C (eight patients treated with prulifloxacin 600 mg once daily for 3 days and undergoing surgery 3 hours after the last dose). Patients to be treated with prulifloxacin were randomly allocated to group B or C. During surgery, samples of blood were collected jointly with healthy tissue removed from the endometrium, proximal fallopian tube, vaginal posterior fornix and portio vaginalis. Ulifloxacin concentrations in plasma and gynaecological tissues were determined by a liquid chromatography-tandem mass spectrometry (LC-MS/MS) bioanalytical method. An intrastudy assessment of the bioanalytical method performance was also conducted for plasma and tissues using calibration and quality control data (spiked samples). RESULTS: Ulifloxacin mean concentrations were always higher in group C than in group B patients, both in plasma (0.76 vs 0.53 microg/mL) and in gynaecological tissues, namely fallopian tube (1.38 vs 0.81 microg/g), posterior fornix (1.48 vs 1.05 microg/g), portio vaginalis (1.46 vs 1.45 microg/g) and endometrium (2.20 vs 1.39 microg/g), as expected after repeated drug administrations. Tissue concentrations observed after repeated administrations were generally higher than the ulifloxacin minimum inhibitory concentrations for pathogens more frequently involved in gynaecological bacterial infections. The mean tissue/plasma ratios ranged between 1.5 and almost 3. CONCLUSION: The results of this study are promising but not fully predictive of clinical or microbiological efficacy for prulifloxacin. There is a need for appropriate clinical trials confirming that prulifloxacin is a useful therapeutic tool in patients with gynaecological bacterial infections.

Penetration of prulifloxacin into sinus mucosa of patients undergoing paranasal sinus elective endoscopic surgery.

The aim of this study was to assess the concentration of ulifloxacin, the active metabolite of prulifloxacin, in sinuses mucosa and plasma of patients with chronic rhinosinusitis, requiring sinus elective endoscopic surgery. Thirty-nine patients (30 males, 9 females; age range 22-77 years) with chronic sinusitis were enrolled, 35 were treated with the investigational medication. Samples from four untreated patients were used to validate the analytical method, while four treated patients dropped out before surgery. One 600 mg prulifloxacin tablet once daily was administered for 5 days before surgery. The last dosing was scheduled from 2 to 12 hours from tissue and plasma sampling. In each patient, two samples of paranasal sinus mucosa (from ethmoid and turbinate, respectively) and one blood sample were collected. Concentrations of ulifloxacin in plasma and sinuses mucosa were measured using validated bioanalytical LC/MS/MS methods. Individual and mean ulifloxacin concentrations in tissues were always higher than the relevant plasma levels. The highest concentrations were observed between 2.5 and 4.5 hours after the last dosing in all districts. The mean tissue/plasma ratios were 2.5 and 3.0 for ethmoid and turbinate, respectively. Data expressed as Area Under the Curves (AUC±SD) showed that ulifloxacin concentrations in the ethmoid were slightly higher (18.68±6.48 µg/g*h) than in turbinate (15.00±2.89 µg/g*h), and definitely higher than in plasma (6.32±1.14 µg/ml*h). The AUC ratios between tissues and plasma were 3.0 for ethmoides and 2.4 for turbinates. One patient reported two treatment-related episodes of diarrhea, which spontaneously resolved after the drug suspension. Results from this study seem to suggest that prulifloxacin showed good distribution in sinus tissues, where it reaches concentrations significantly higher than in plasma. These findings strongly call for confirmatory clinical trials in patients with bacterial rhinosinusitis.

Pharmacokinetics and tolerability of prulifloxacin after single oral administration.

The pharmacokinetic properties and tolerability of three different strengths of prulifloxacin (CAS 123447-62-1), a new antibacterial agent prodrug of AF3013 (CAS 112984-60-8), have been investigated in a randomized, cross-over study performed in 12 Caucasian male subjects (age range 19-34 years). Prulifloxacin was administered as a single oral dose at the dosages of 300, 450 and 600 mg. Plasma concentrations of the active metabolite AF3013 were determined in blood samples collected before the administration (pre-dose) and at 15, 30, 45 min, 1, 1.5, 2, 3, 4, 6, 8, 10, 12, 16, 24, 36 and 48 h after dosing. Urine samples were also collected. Determination in biological samples was performed using validated and specific HPLC methods. The following parameters were calculated: Cmax, tmax, AUC0-t, AUC0--infinity, t1/2, V/F, Aeut, CLren and fe. The analysis of variance performed on dose-normalized data after logarithmic transformation evidenced no statistically significant differences between the three doses concerning Cmax and AUC. Friedman's test applied to tmax and t1/2 did not show any statistically significant difference between doses. A significant linear relationship between doses and AUC0-infinity was detected (p < 0.05). Very high urinary concentrations and the relatively long terminal half-life (10-12 h) suggest that a once-daily application would show adequate clinical efficacy, especially in urinary infections. The safety profile of the three doses was very good.