Differences in bioavailability between 60 mg of nifedipine osmotic push-pull systems after fasted and fed administration
Bibliographic record
Abstract
OBJECTIVES: This study was designed to evaluate and compare the bioavailability of two osmotically active formulations of 60 mg nifedipine, Gen-Nifedipine extended release Test tablets (Genpharm ULC, Etobicoke, ON, Canada) and Adalat XL Reference tablets (Bayer Healthcare AG, Leverkusen, Germany) after single dose fasted and fed administration. MATERIALS AND METHODS: The study was performed following a 4-period crossover design with both investigational products obtained from marketed batches. The complete pharmacokinetic evaluation was carried out in 26 healthy male subjects with a median age of 29.5 years (range 18 - 44 years), mean weight of 79.7 kg (range 66.0 - 97.5 kg), and a mean body mass index (BMI) of 24.1 kg/m(2) (range 22.1 - 26.9 kg/m(2)). Tablets were administered with tap water either under fasting conditions or immediately following a high-fat, high-calorie breakfast. Blood samples were taken predose and at pre-defined time points until 48 h post dosing. Samples were protected from light during handling and frozen until analysis. A validated LC-MS/MS method was used for the quantification of nifedipine in plasma samples. All kinetic parameters were determined model-independently for each treatment directly from measured concentrations. Monitoring of subject safety was accomplished by routine monitoring of blood pressure, heart rate and probing for adverse events. RESULTS: In-vitro dissolution curves show later onset and considerably lower quantity of nifedipine release from Test compared to Reference tablets. Under fasting conditions total and maximum exposure, represented by geometric mean AUC(0-tlast)- and C(max)-values, respectively were 466.7 h*ng/ml (AUC(0-tlast)) and 21.9 ng/ml (C(max)) for Test and 507.8 h*ng/ml (AUC(0-tlast)) and 22.0 ng/ml (C(max)) for Reference tablets. However, the Test product exhibited a notably longer lag-time and less rapid onset of absorption than the Reference tablets. Moreover, the plateau phase is maintained for about 14 hours on Test but for almost 20 hours on Reference. Point estimates (PE) and associated 90% confidence intervals (CI) were determined as 91.8% and 79.9 - 105.5% for AUC(0-tlast), as well as 99.8% and 88.6 - 112.4% for C(max). Larger differences were found for AUC(0-9h) (PE: 54.8%; CI: 45.8 - 65.5%) determined as parameter for early exposure. Under fed conditions, although the mean plasma concentration time curves look similar in shape, concentrations of Test compared to Reference tablets are considerably lower at all time points until 36 hours after dosing. Again the lag time in onset of drug absorption is notably longer for the Test product. Both, total and maximum exposure, represented by geometric mean values for AUC(0-tlast) and C(max), were considerably lower (differences also statistically significant) after administration of Test with 481.8 h*ng/ml for AUC(0-tlast) and 25.3 ng/ml for C(max) in comparison to Reference tablets with 595.9 h*ng/ml for AUC(0-tlast) and 31.9 ng/ml for C(max). Test/Reference point estimates (PE) and associated 90% confidence intervals (CI) were determined as 80.7% and 73.7 - 88.5% for AUC(0-tlast), as well as 79.6% and 70.3 - 90.0% for C(max). Differences were also even more expressed for AUC(0-9h) (PE: 54.9%; CI: 47.4 - 63.5%) determined as parameter for early exposure. CONCLUSION: The results indicate that although both products are osmotic release systems they are not bioequivalent according to the accepted standards. This difference between both osmotic delivery systems might be substantiated by the fact that the core of the Test product is designed as a monolayer system (containing both, the active ingredient and the osmotic component) while Reference tablets consist of two separate layers. The observed pharmacokinetic differences may have an impact on blood pressure control in patients and thus, should be kept in mind when switching during treatment.
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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 | 0.003 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.002 |
| Insufficient payload (model declined to judge) | 0.000 | 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".