ABSTRACT
The fragmentation pathways of the three ginkgolides (ginkgolides A, ginkgolides B, ginkgolides C) have been studied with high resolution and high mass accuracy using quadrupole time-of-flight mass spectrometry in negative ion mode in this paper. The results indicate that the three ginkgolides have similar fragmentation pathways, including four kinds of common cleavage pathways and one common characteristic ion. In high quality regions, the typical fragmentation pathways of the three ginkgolides are lactone ring opening with continuous loss of CO, CO₂,and loss of H₂O. In low quality regions, the common characteristic fragment ion of the three ginkgolides at 72.993 6 is formed by C rings cleavage. Also, the common fragment ions of ginkgolides A and ginkgolides B at 141.018 8, 125.023 8, 113.024 0, 97.029 1 are formed by A rings cleavage. The study of fragmentation pathways could be adopted for the structural identification of the ginkgolides and their metabolites.
Subject(s)
Ginkgolides , Chemistry , Mass Spectrometry , Spectrometry, Mass, Electrospray IonizationABSTRACT
OBJECTIVE:To study the preparative methods of the long-circulating solid lipid nanoparticles(LSLN)carrying ginkgolides A and B(GAB)and to study the physicochemical characteristics of the GAB-LSLN.METHODS:GAB-LSLN was prepared by ultrasonication or high pressure homogenization.Transmission electron microscopy was employed to study its shape.Particle size,zeta potential,and entrapment efficiency of GAB-LSLN were determined,and its stability after storage under room temperature for 4 weeks was determined as well.RESULTS:The GAB-LSLN prepared by ultrasonication was platelet-shaped and irregular,and that prepared by high pressure homogenization was spherical and regular in shape.The particle diameters of GAB-L SLN prepared by ultrasonication and high pressure homogenization were(219.6?14.3)nm and(173.9?10.4)nm respectively(P0.05).CONCLUSION:High pressure homogenization is superior to ultrasonication in that the prepared GAB-LSLN has small particle size,high stability and high entrapment efficiency.