Comparative bioavailability between two tramadol once-daily oralformulations
Bibliographic record
Abstract
The aim of this study was to compare the pharmacokinetic profile and oral bioavailability of Tramadol Contramid once-daily (o.d.) 200 mg tablets (Labopharm, Canada) with that of Zytram 200 mg tablets (Zambon, Spain), following single-dose administration in 26 healthy volunteers. The study had an open, randomized, crossover design with a 7-day wash-out. Data from 24 subjects were used for the pharmacokinetic (PK) analysis. Racemic tramadol and racemic O-demethyltramadol (M1) were assayed in plasma using a liquid chromatography/tandem mass spectrometry method. Primary PK parameters estimated were AUC(0-t), AUC(0-infinity), C(max), C(24 h), and T(max). Results were compared using an ANOVA, and the residual variability thereby obtained was used to construct the classical 90% confidence intervals. The parametric Schuirmann's test was also performed. T(max) was analyzed by a nonparametric approach. For both racemic tramadol and racemic O-demethyltramadol, the ANOVA showed a statistically significant formulation effect. Significantly higher values were obtained for Tramadol Contramid o.d. for all PK parameters, except for T(1/2). For Tramadol Contramid o.d., mean tramadol plasma levels were maintained at a plateau level above 200 ng/ml from 4 to 16 h after dose, while for the reference formulation, that level was sustained from 4 to only 6 h. Consistent results for both formulations were obtained for the metabolite. At the end of the dosing interval, plasma tramadol and O-demethyltramadol concentrations were 39% and 49% higher, respectively, for Tramadol Contramid o.d. than those for Zytram (p < 0.0001). Tramadol Contramid o.d. could be considered suprabioavailable to Zytram o.d.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".