RESUMEN
Methocarbamol is a central nervous system depressant with skeletal muscle relaxant properties indicated to treatspasms. During the synthesis of methocarbamol from guaifenesin, both potential known and an unknown impurity(0.05%–0.1%), high performance liquid chromatography) were observed. The later was separated using preparativeliquid chromatography. Upon the findings of the 1H nuclear magnetic resonance, Mass, and IR spectral analysis, theunknown impurity was designated as a β-isomer of methocarbamol [1-hydroxy-3-(2-methoxy phenoxy) propan-2-ylcarbamate]. The impurity isolation, its structure elucidation, and the potential formation mechanism are discussed.
RESUMEN
Objective To establish a HPLC method for determination of 18β-isomer in magnesium isoglycyrrhizinate. Methods The determination was performed by Agilent Extend-C18 column ( 4. 6 mm × 250 mm, 5 μm ) . Mobile phase consisted of 0. 1 mol·L-1 potassium dihydrogen phosphate buffer solution ( adjusted to pH 7. 0 with potassium hydroxide )-acetonitrile (80︰20) at the flow rate of 1.0 mL·min-1. The column temperature was 30 ℃, and the detection wavelength was set at 250 nm. Results The resolution of magnesium isoglycyrrhizinate and 18β-isomer was greater than 2.0. The linear range of them was 0.41-2.46μg·mL-1( r=0.9998) , the detection limit was 0.21 ng, and the average recovery were 100.2%,99.1%, 110.2%,RSD were 0.9%,0.1%,0.2%(n=3). Conclusion The method is simple and accurate, and can be used for determination of 18β-isomer in magnesium isoglycyrrhizinate.
RESUMEN
Objective To establish a HPLC method for determination of 18β-isomer in magnesium isoglycyrrhizinate. Methods The determination was performed by Agilent Extend-C18 column ( 4. 6 mm × 250 mm, 5 μm ) . Mobile phase consisted of 0. 1 mol·L-1 potassium dihydrogen phosphate buffer solution ( adjusted to pH 7. 0 with potassium hydroxide )-acetonitrile (80︰20) at the flow rate of 1.0 mL·min-1. The column temperature was 30 ℃, and the detection wavelength was set at 250 nm. Results The resolution of magnesium isoglycyrrhizinate and 18β-isomer was greater than 2.0. The linear range of them was 0.41-2.46μg·mL-1( r=0.9998) , the detection limit was 0.21 ng, and the average recovery were 100.2%,99.1%, 110.2%,RSD were 0.9%,0.1%,0.2%(n=3). Conclusion The method is simple and accurate, and can be used for determination of 18β-isomer in magnesium isoglycyrrhizinate.