LC-MS/MS method for the simultaneous quantification of luteolin, wedelolactone and apigenin in mice plasma using hansen solubility parameters for liquid-liquid extraction: Application to pharmacokinetics of Eclipta alba chloroform fraction.

Eclipta alba (Bhringraj) in ayurveda has been widely used as a traditional medicine for its multi-therapeutic properties for ages. Luteolin (LTL), wedelolactone (WDL) and apigenin (APG) are the three main bioactive phytochemicals present in Eclipta alba extract. However there was a lack of sensitive bioanalytical method for the pharmacokinetics of these free compounds in plasma which majorly contributes for their activities after oral administration of Eclipta alba. The present study aims to develop a sensitive, rapid and reliable liquid chromatography tandem mass spectrometry (LC-MS/MS) method for the simultaneous estimation of mice plasma concentrations of LTL, WDL and APG using quercetin as an internal standard for the pharmacokinetic analysis. Analytes were separated on Phenomenex Luna C18 (150 × 4.6 mm, 3.0 µm) column with mobile phase containing methanol: acetonitrile (90: 10, v/v) and 0.1% formic acid in 10 mM ammonium formate buffer in the ratio of 70: 30 (v/v) in isocratic mode. Liquid-liquid extraction was optimized using Hansen solubility parameters and diethyl ether finalized as an extraction solvent for the recovery ranging from 61 to 76% for all analytes in mice plasma. The validated method has an accuracy and precision over the linearity range of 0.1-200 ng/mL with a correlation coefficient (r2) of ≥0.997. The intra and inter-day assay accuracy was between 98.17 and 107% and 95.83-107.89% respectively and the intra and inter day assay precision ranged from 0.37-6.05% and 1.85-10.76%, respectively for all the analytes. This validated method can be used for future clinical investigation studies of Eclipta alba extracts.

Hansen solubility parameters for assay method optimization of simvastatin, ramipril, atenolol, hydrochlorothiazide and aspirin in human plasma using liquid chromatography with tandem mass spectrometry.

A simple, specific, sensitive, validated method was developed using liquid chromatography with tandem mass spectrometry with electrospray ionization of human plasma for the simultaneous estimation of drugs (simvastatin, ramipril, atenolol, hydrochlorothiazide, and aspirin) of PolycapTM capsule used in cardiovascular therapy. The interaction of these actives including internal standards between the stationary and mobile phase were investigated using Hansen solubility parameters. Chromatographic separation was performed on Phenomenex Synergi Polar-RP (30 × 2 mm, 4 µm) column with a gradient mobile phase composition of acetonitrile and 5 mM ammonium formate for positive mode and 0.1% formic acid in both water and acetonitrile for negative mode. The flow rate and runtime were 1.0 mL/min and 3.5 min, respectively. Sample extraction was done by protein precipitation using acetonitrile, enabling a fast analysis. The calibration ranges from 0.1 to 100, 0.1 to 100, and 1 to 1000 ng/mL for simvastatin, ramipril, and atenolol using internal standard carbamazepine in positive mode, respectively, whereas it was 0.3-300 and 2-2000 ng/mL for hydrochlorothiazide and aspirin using internal standard 7-hydroxy coumarin in negative mode, respectively. Hansen solubility parameters can be used as a high-throughput optimizing tool for column and mobile phase selection in bioanalysis. This validated bioanalytical method has the potential for future fixed dose combination based preclinical and clinical studies that can save analysis time.