ABSTRACT
OBJECTIVE: To develop an UHPLC-MS/MS method for the determination of R-/S-2-(2-hydroxypropanamido) benzoic acid (R-/S-HPABA) in rat urine, feces and bile and apply the method to study the excretion of R-/S-HPABA in rats. METHODS: After liquid-liquid extraction by ethyl acetate,the separation was achieved on a Thermo Syncronis C18 column (2.1 mm×50 mm, 1.7 μm) using mobile phase consisting of solvent A (methanol) and solvent B (0.1% formic acid) at a flow rate of 0.4 mL•min-1. The concentration of R-/S-HPABA after single dose oral administration of 50 mg•kg-1 R-/S-HPABA to rats was detected by UHPLC-MS/MS method. RESULTS: The calibration curve was linear over the range of 0.002-5 μg•mL-1 and the lower limit of quantification (LLOQ) was 0.002 μg•mL-1. The intra-and inter-day RSDs were less than 13.0% and the accuracy (relative error) of R-/S-HPABA was within -7.5%-4.2%. The average recoveries were (87.3±3.4)%-(104.4±7.0)%. After intragastric administration of R-HPABA and S-HPABA at a dose of 50 mg•kg-1, the cumulative amounts of R-HPABA and S-HPABA excreted in the urine (0-48 h) were (536.1±29.7) and (771.7±38.6) μg, the urinary excretion amounted to 4.9% and 7.0% of the dosage, respectively; the cumulative amounts of R-HPABA and S-HPABA excreted in feces (0-48 h) were (3 963.0±345.2) and (4 771.8±355.0) μg, the fecal excretion amounted to 36.0% and 43.4% of the dosage, respectively; the cumulative amounts of R-HPABA and S-HPABA excreted in bile (0-12 h) were (150.6±30.3) and (747.7±89.2) μg, the biliary excretion amounted to 1.4% and 6.8% of the dosage, respectively; the summation of urinary, fecal and biliary excretion amounted to 42.3% and 57.2% of the dosage in rats for R-HPABA and S-HPABA, respectively. The cumulative amounts of S-HPABA excreted in the urine, feces and bile were higher than those of R-HPABA. CONCLUSION: This UHPLC-MS/MS method is suitable for the study of the excretion of R-/S-HPABA in rats. The excretion of the two enantiomers in rats shows significant stereoselectivity difference.
ABSTRACT
Compared with the racemate of chiral drugs, enantiopure chiral drugs have been the hot spot of drug research because of their higher selectivity and lower side-effects. Although remarkable progress of asymmetric synthesis has been achieved in the last decades, chiral resolution is regarded as an important approach to obtain chiral drugs. Recent research advancements in the field of chiral resolution of racemic drugs and intermediates are reviewed here. It is clear that combination of chiral separation and racemization to improve the resolution efficiency has become a trend of chiral resolution. In addition, we also introduce some novel resolution methods, such as chiral extraction, membrane resolution, and resolution using nanoparticles.
ABSTRACT
Affinity chromatography (AC)is a type of liquid chromatography that makes use of biological-like interactions for separation and specific analysis of bioactive components. It has been widely used as a high-throughput screening method for the separation,screening and purification of the target molecules from complex samples with advantages such as high selectivity and high recovery efficiency.This article summarizes the biological effects of affinity chromatography, molecular imprinting chromatography, and dye ligands affinity chromatography.The review also encompasses the application of AC in the separation of chiral drugs,screening of active components,purification of target protein,and mechanism of the drug-protein interaction.Moreover,the prospects of its applications are also discussed.
ABSTRACT
Affinity chromatography (AC)is a type of liquid chromatography that makes use of biological-like interactions for separation and specific analysis of bioactive components. It has been widely used as a high-throughput screening method for the separation,screening and purification of the target molecules from complex samples with advantages such as high selectivity and high recovery efficiency.This article summarizes the biological effects of affinity chromatography, molecular imprinting chromatography, and dye ligands affinity chromatography.The review also encompasses the application of AC in the separation of chiral drugs,screening of active components,purification of target protein,and mechanism of the drug-protein interaction.Moreover,the prospects of its applications are also discussed.
ABSTRACT
A pepsin modified poly (glycidyl methacrylate-ethyleneglycol dimethacrylate)(poly (GMA-EDMA)) capillary monolith (32 cm ×75 μm,22cm effective lenth)was applied in exploring the interaction between nefo-pam enantiomers and bovine serum albumin (BSA),mode of frontal analysis was selected to measure the binding constant,number of binding sites and the location of binding sites of BSA to both nefopam enantiomers.The opti-mal CEC conditions obtained were a running buffer consisted of 15 mmol /L ammonium acetate at pH 5.5,separa-tion voltage 5.0 kV,detection wavelength 215 nm,injection 10 kV ×6 s,solvent of samples consisted of 50 mmol/L ammonium acetate at pH 7.4.The results indicated that the monolith could provide a satisfactory resolution between the two enantiomers plateaus,BSA in the binding system didn′t disturb the separation or determination of nefopam enantiomers in electrochromatography.The frontal analysis demonstrated that BSA has only one binding site with both enantiomers,the binding constants (K)were 443 L/mol and 527 L/mol,respectively,and the dis-placement experiments indicated that binding site of both isomers to BSA molecule was the Sudlow siteⅡ.