Determination of nimodipine in plasma by HPLC-MS/MS and pharmacokinetic application

A Design-assisted Spectrofluorometric Method Utilizing a One-pot Fluorescent Probe for the Quantitation of some Calcium Channel Blockers

Based on their reaction with highly fluorescent carbon quantum dots (CQDts), a precise and reliable spectrofluorometric approach was developed for the determination of three calcium channel blockers. The studied drugs are: lercanidipine, nimodipine and nifedipine. (CQDts) were produced using a one-step hydrothermal method with ascorbic acid as the carbon source. The produced CQDts were capped by alcohol to create yellow emitters displaying a high fluorescence emission at 524 nm when excited at 325 nm. The fluorescence intensity of CQDts was noticeably quenched by each of the three calcium channel blockers. The relation between their concentrations and fluorescence quenching is linear over the concentration range of 0.5-20 µg/mL for each of the three drugs. A full factorial design was used to optimize the effect of variable factors. Therefore, under optimum experimental design conditions, the detection limits for lercanidipine, nimodipine, and nifedipine were 0.11 ± 1.09, 0.10 ± 0.25 and 0.12 ± 0.71 µg/mL, respectively. The LOQ was 0.33, 0.30, and 0.37 µg/mL respectively. The quenching of fluorescent CQDts occurred through the inner filter effect (IFE) for nimodipine, while it was mixed with dynamic quenching for lercanidipine and nifedipine. The proposed method was effectively used to determine the cited drugs in their pharmaceutical products and had an acceptable level of precision. The selectivity of the CQDts system towards the studied drugs was examined indicating no interference from interfering species.

SFC-MS/MS method for simultaneous determination of nimodipine and 3-n-butylphthalide in beagle plasma: application to pharmacokinetic interaction study

Aim: Nimodipine and 3-n-butylphthalide are co-administered to treat vascular dementia, but the pharmacokinetic interaction between the two drugs is still unknown. Therefore, a robust, high-throughput and economical supercritical fluid chromatography-ESI-MS/MS method has been initially developed to simultaneously determine nimodipine and 3-n-butylphthalide in beagle plasma, in order to study the safety of co-administration. Materials & methods: After a simple protein precipitation procedure, isocratic elution with mobile phase of CO₂ and methanol (containing 0.3% formic acid and 2 mM ammonium acetate) was applied to minimize run time and facilitate sensitive and high-throughput bioanalysis. The method was fully validated according to US FDA Guidance. The validated method was then successfully applied in a pharmacokinetic interaction study. Results: The results indicated there is no significant pharmacokinetic interaction between the two drugs.

Enantioselective assay of nimodipine in human plasma using liquid chromatography-tandem mass spectrometry

Nimodipine is a dihydropyridine calcium channel blocker that exhibits higher selectivity toward cerebral blood vessels compared with other members of the same class. It has been shown to improve outcomes and prevent delayed cerebral ischemia in the setting of aneurysmal subarachnoid hemorrhage, a life-threatening brain bleed. Nimodipine is a chiral compound and it is marketed as a racemic mixture of (+)-R and (-)-S enantiomers. (-)-S-Nimodipine is approximately twice as potent a vasorelaxant as the racemic mixture and is more rapidly eliminated than the (+)-R counterpart following oral dosing. Few analytical procedures have been reported to determine nimodipine enantiomers in biological samples; however, the reported methods were time-consuming, involved multistep extraction procedures and required large sample volumes. Herein, we present an LC-MS/MS method for quantifying nimodipine enantiomers in human plasma using a small sample volume (0.3 ml) and a single liquid-liquid extraction step. The peak area ratios were linear over the tested concentration ranges (1.5-75 ng/ml) with r²  > 0.99. The intraday CV and percentage error were within ±14% while the interday values were within ±13%, making this analytical method feasible for research purposes and pharmacokinetic studies.

Development and optimization of a supercritical fluid chromatography tandem mass spectrometry method for the high-throughput determination of nimodipine in beagle plasma

A simple, sensitive, and efficient supercritical fluid chromatography with tandem mass spectrometry method was established for the determination of nimodipine in beagle plasma. One-step protein precipitation with acetone was used to extract the analytes from the plasma. Nitrendipine was used as the internal standard. The chromatographic separation was achieved on an ACQUITY UPC² ™ BEH 2-EP column, and a gradient elution program was applied at a flow rate of 1.5 mL/min. The detection was carried out on a triple quadrupole tandem mass spectrometer with an electrospray ionization source operating in positive ion mode. Quantification was performed using multiple reaction monitoring of the transitions of m/z 419.3→301.3 for nimodipine and m/z 361.4→315.2 for nitrendipine. A satisfactory linearity was obtained over the concentration range of 0.5-800 ng/mL (r > 0.996). The intra- and interday precision and accuracy results were <9.1% across the quality control levels. The peak concentration and area under concentration-time curve (0-720 min) values of the test and reference formulations were 279.28 ± 211.46 and 265.13 ± 149.26 ng/mL, 25608.00 ± 17553.65 and 28553.67 ± 20207.92 ng·min/mL, respectively. The validated method was successfully applied to reveal the pharmacokinetic profiles of nimodipine in beagle dogs after oral administration. Moreover, the analytical method could be used for further bioequivalence studies.