Enantioselective and sensitive determination of carvedilol in human plasma using chiral stationary-phase column and reverse-phase liquid chromatography with tandem mass spectrometry

Chemometric optimization of salting-out assisted liquid-liquid extraction (SALLE) combined with LC-MS/MS for the analysis of carvedilol enantiomers in human plasma: Application to clinical pharmacokinetics

Carvedilol is a commonly used antihypertensive whose oral absorption is limited by low solubility and significant first-pass metabolism. This work aimed to apply chemometrics for the optimization of a salting-out assisted liquid-liquid extraction (SALLE) combined with LC-MS/MS to analyze carvedilol enantiomers in plasma samples. Method development and validation were driven for application in pharmacokinetic studies. Parameters that influence the efficiency of SALLE were evaluated using a fractional factorial 24-1 design with 4 factors and a central composite design was used to evaluate the optimal extraction condition. Carvedilol enantiomers and the internal standard lidocaine were separated on an Astec® Chirobiotic® V column and a mixture of methanol:ethanol (90:10, v/v) with 0.02% diethylamine and 0.18% acetic acid as mobile phase. The positive ion mode on electrospray ionization was used to monitor the transitions of m/z 407 > 100 and 235 > 86 for carvedilol enantiomers and lidocaine, respectively. Acetonitrile and ammonium acetate solution were selected for sample preparation by SALLE. Surface graphs and the desirability test were used to define the optimized SALLE conditions which resulted in 93% recovery for both carvedilol enantiomers. The method was linear in the range of 0.5 to 100 ng/mL in plasma, with a lower limit of quantification of 0.5 ng/mL. Within-run and between-run precision (as the relative standard deviation) were all < 9.74% and accuracy (as relative error) did not exceed ± 10.30%. Residual effect and matrix effect were not observed. Carvedilol enantiomers were stable in plasma under the storage, preparation, and analysis conditions. The validated method was successfully applied to analyze carvedilol in plasma samples from patients previously submitted to a Roux-en-Y gastric bypass surgery treated with a single oral dose of 25 mg racemic-carvedilol. Higher plasma concentrations were observed for (R)-(+)-carvedilol when compared to (S)-(-)-carvedilol in two patients post-bariatric surgery.

Hollow fiber based liquid phase microextraction with high performance liquid chromatography for the determination of trace carvedilol (β-blocker) in biological fluids

A hollow-fiber liquid-phase microextraction (HF-LPME), followed by high-performance liquid chromatography–ultraviolet (HPLC–UV) method for the trace determination of carvedilol (β-blocker) in biological fluids, has been described. The separation was achieved using Inertsil ODS-3 C18 (250 mm × 4.6 mm, 3 μm) column with a mobile phase composition of 10 mM phosphate buffer (pH 4.0)–acetonitrile (50:50, v/v) at a flow rate of 1.0 mL/min, under isocratic elution. Several parameters (i.e., type of organic solvent, donor phase pH, concentration of acceptor phase (AP), stirring rate, extraction time, and salt addition) that affect the extraction efficiency were investigated. The optimum HF-LPME conditions were as follows: dihexyl ether as an organic solvent; donor phase pH, 10.7; 0.1 M HCl (AP); 1100-rpm stirring rate; 60-min extraction time; and no salt addition. These parameters have been confirmed using design of experiments. Under these conditions, an enrichment factor of 273-fold was achieved. Good linearity and correlation coefficient were obtained over the range 5–1000 ng/mL (r2 = 0.9994). Limits of detection and quantitation were 1.2 and 3.7 ng/mL, respectively. The relative standard deviation at 3 different concentration levels (5, 500, and 1000 ng/mL) were less than 13.2%. Recoveries for spiked urine and plasma were in the range 80.7–114%. The proposed method is simple, sensitive, and suitable for the determination of carvedilol in biological fluids.

Temperature and eluent composition effects on enantiomer separation of carvedilol by high-performance liquid chromatography on immobilized amylose-based chiral stationary phases

Carvedilol is a chiral drug with potent antihypertensive and antianginal activities. Although it is clinically used as a racemic mixture, its enantiomers show different pharmacokinetic and pharmacodynamic profiles. Here, the direct chiral separation of racemic drug by high performance liquid chromatography using two immobilized-type amylose-based chiral stationary phases is presented. Some chromatographic parameters, such as retention and selectivity, were determined under multimodal eluent conditions and different temperatures. A temperature-dependent inversion of the elution order of enantiomers was observed in the operative temperature range of chiral chromatographic support. Finally, an effective direct enantioselective method was successfully applied to the separation of the enantiomers of carvedilol on a semipreparative scale.

A dispersive liquid-liquid microextraction and chiral separation of carvedilol in human plasma using capillary electrophoresis

BACKGROUND

Development of simple, rapid and precise analysis of chiral drugs in biological samples is an important issue. Dispersive liquid-liquid microextraction in combination with CE using field amplified sample injection has been of interest because of its capability to analyze trace amount of drugs.

METHODS

Dispersive liquid-liquid microextraction-CE-field amplified sample injection was employed for chiral separation of carvedilol in human plasma using UV-DAD detector and the developed method has been validated according to US FDA method validation guideline for bioanalysis.

RESULTS

The method was linear over a concentration range of 12.5-100 ng/ml for each carvedilol enantiomer (R(2) = 0.998) and the mean recoveries ranged from 91 to 107%.

CONCLUSION

The method was adapted for sensitive, selective and rapid determination of carvedilol enantiomers in human plasma samples.