An isatin derivative ofβ-cyclodextrin Schiff base was first synthesized by the condensation reaction between the carbonyl group of isatin and ethylenediamino group of the mono-substituted β-cyclodextrin. The Schiff base ligand was chemically linked to homemade ordered mesoporous SBA-15 silica gel via 3-( triethoxysilyl) propyl isocyanate coupling agent. In this way, a novel isatin derivative of β-cyclodextrin-bonded SBA-15 stationary phase ( ISCDP) was prepared for HPLC. Its chemical and physical parameters were characterized by infrared spectroscopy, mass spectroscopy, elemental analysis, thermogravimetric analysis, scanning electron microscopy, transmission electron microscopy, X-ray diffraction and BET specific surface area analysis. The basic chromatographic property of ISCDP was evaluated by using polar halogenated uracils and disubstituted benzene positional isomers as solute probes in reversed-phase chromatography. ISCDP was also used to enantioseparate twoβ-blocker drugs in polar organic mode and two dansyl amino acids in reversed-phase mode, respectively. The related chromatographic separation mechanism was also discussed. Above studies were expected to provide experimental basis for the practical application of ISCDP in the future. The results showed that the introduction of isatin indole ring could enhanced the reversed-phase chromatographic separation ability of ISCDP for halogenated uracils within 7 min. The new packing also exhibited high stereoselectivity for the position isomers of nitroaniline, aminophenol and benzenediol, in which the para isomers were finally eluted due to strong inclusion interaction between the isatin derivative of β-cyclodextrin ligand and the isomers. Meanwhile, the introduction of isatin indole ring could also improve the chiral separation ability of ISCDP. For example the fast enantioseparations of chiral β-adrenergic blockers and dansyl-amino acids on ISCDP were achieved within 20 min (Rs>1. 3). Obviously, besides hydrophobicity, various synergistic interactions could enhance the separation selectivities of the new stationary phase for chiral and achiral analytes, including dipole-dipole, hydrogen bonding,π-π and inclusion interactions. The ordered pore structure of SBA-15 facilitated to fast and efficient separation and analysis for drugs with good permeability and low mass transfer resistance.

A 6-azido-β-cyclodextrin was synthesized and derivatized with p-nitrophenyl isocyanate as chiral ligand. Following that the ligand was chemically bonded to mesoporous SBA-15 via a ‘Click Chemistry ’ reaction of the azido group with alkynyl group. A new p-nitrophenylcarbamoylatedβ-cyclodextrin bonded SBA-15 chiral stationary phase ( NPCSP ) for HPLC was obtained. The new stationary phase was first used to enantioseparate propranolol in human plasma under the polar organic solvent mode. The effects of methanol content , additive concentration of glacial acetic acid/triethylamine in mobile phase and the temperature on the enantioseparation were studied. The optimal chromatographic conditions were as follows: mobile phase was acetonitrile/methanol/glacial acetic acid/triethylamine (90:10:1. 25:2. 25, V/V), temperature 288 K, flow rate of 0. 5 mL/min, injection volume of 20 μL, detection wavelength at 290 nm. The resolution was 2. 04 with a short run time (< 15 min) under the above conditions. The composition of propranolol in plasma was quantitatively measured by HPLC-MS selected ion monitoring mode ( [ M +H ]+ m/z 260 . 10 ) with hydrochlorothiazide as internal standard. And linear range was 2. 5-250 μg/L and with a good linear relationship. The detection limit was 1 μg/L according to S/N=3. The experimental results showed that the chiral stationary phase exhibited excellent chiral separation ability to propranolol and the analysis method for propranolol in plasma was sensitive, accurate, simple and fast, which could be used for the determination of propranolol in plasma and pharmacokinetic studies.

BACKGROUND:Intervertebral disc degeneration is an important cause of low back pain.At present,there are many modeling methods for disc degeneration in China and abroad,but there is not a model for low back pain due to disc degeneration. OBJECTIVE:To compare the effect of mechanical puncture combined with tumor necrosis factor α and complete Freund's adjuvant with a conventional disc mechanical puncture alone. METHODS:A total of 18 male adult Sprague-Dawley rats were randomly divided into 3 groups,with 6 animals in each group.No treatment was given in the blank group.Animal models of intervertebral disc degeneration were made in the L4-5 segments of rats in the control using conventional mechanical puncture.In the experimental group,on the basis of mechanical puncture,tumor necrosis factor α+complete Freund's adjuvant was injected into the L4-5 intervertebral discs using a microinjector to establish a model of disc degeneration induced by mechanical puncture combined with inflammatory factors.Four weeks after surgery,the pain threshold of rats was measured by the hot plate method for assessing the perception of heat injury in rats with intervertebral disc degeneration.MRI examination was performed to observe the disc degeneration in each group.ELISA was used to detect the levels of serum tumor necrosis factor α,interleukin 1β,interleukin 6 and prostaglandin E2.Hematoxylin-eosin and Safranin O-fast green staining were used to observe the morphological changes of the disc. RESULTS AND CONCLUSION:In terms of pain,the behavioral pain threshold of the experimental group was continuously decreased,and the levels of serum inflammatory factors were significantly higher compared with the control group.In terms of morphology,the MRI results showed that the L4-5 nucleus pulposus signal completely disappeared in the experimental group.Histopathological results showed that in the control group,the nucleus pulposus was intact,more notochord cells were visible,and some fiber rings were ruptured,while in the experimental group,there are fewer notochord cells and the structure of the nucleus pulposus and fibrous ring is disturbed,with the boundary disappearing.To conclude,mechanical puncture combined with tumor necrosis factor alpha and complete Freund's adjuvant can successfully establish a discogenic low back pain model in rats.This operation is simple and economical to achieve obvious disc degeneration and low back pain,with greatly shortened molding cycle.This model can be used as a reference for studying discogenic low back pain models.