Simultaneous Determination of Candesartan and Hydrochlorothiazide in Human Plasma by HPLC-MS/MS
Bibliographic record
Abstract
Introduction. Combined drugs have the greatest efficacy and safety in arterial hypertension treatment. The combination of candesartan and hydrochlorothiazide (AT1-receptor antagonist and a thiazide diuretic, respectively) provides high efficiency of antihypertensive combination therapy, therefore it is widely used in medical practice. Developing a method for simultaneous determination of candesartan and hydrochlorithiazide in human blood plasma is necessary for performing the analytical part of pharmacokinetic studies and bioequivalence studies of multicomponent drugs. Aim. The aim of this study is to develop a method for quantitative determination of candesartan and hydrochlorothiazide in human plasma by high-performance liquid chromatography – tandem mass spectrometry (HPLC-MS/MS) for further bioequivalence studies. Materials and methods . Determination of candesartan and hydrochlorothiazide in human plasma by HPLC-MS/MS. The samples were processed by acetonitrile protein precipitation. Internal standard: mixed solution of valsartan and indapamide. Mobile phase: 0.1 % formic acid solution in water (eluent A), 0.1 % formic acid in acetonitrile (eluent B). Column: Phenomenex Luna Phenyl-Hexyl, 50x4.6 mm, 5 μm. Analytical range: 2.00– 300.00 ng/mL for candesartan, 2.00–200.00 ng/mL for hydrochlorothiazide in human plasma. Ionization source: electrospray ionization. Detection conditions: 441.10 → 192.00 m/z, 441.10 → 263.15 m/z (candesartan), 295.85 → 269.00 m/z (hydrochlorothiazide), 436.00 → 207.05 m/z (valsartan), 363.85 → 132.10, 363.85 → 189.00 m/z (indapamide). Results and discussion . This method was validated by selectivity, matrix effect, calibration curve, accuracy, precision, spike recovery, the lower limit of quantification, carry-over effect and stability. The developed method meets the requirements for conducting bioequivalence studies of medicinal products within the framework of the Eurasian Economic Union. Conclusion. The analytical range was 2.00–300.00 ng/mL for candesartan, 2.00–200.00 ng/mL for hydrochlorothiazide in human plasma. The method was applied in BE study of the combination of candesartan and hydrochlorothiazide.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.002 | 0.002 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.002 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.002 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 0.001 |
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 source (direct Gemma or distilled Codex), 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".