Preparation And In Vivo Pharmacokinetic Study Of Matrine Pellets As A Colon-targeting Sustained Release System

Objective To prepare matrine colon-targeting sustained release pellets using Eudragit S100as colonic enteric coating material; to establish an ultra-high-performance liquidchromatography-tandem mass spectrometry (LC-MS/MS) method to determine theconcentration of matrine in beagle plasma; to study the pharmacokinetics of matrinecolon-targeting sustained release pellets in beagle dogs.Method1. Preparation of matrine pellets: First, the core pellets were prepared byextrusion-spheronization technology, i.e. the prescription and adhesive were optimized byusing surface morphology, roundness, tap density, product yield as indicators. Secondly,Matrine colon-targeting sustained release pellets were prepared by fluidized bed coatingtechnology, i.e. the weight gain of gowns and colonic enteric coating were optimized by usingdrug release rate as an indicator. Finally, the UV method was established to determine thecontents of matrine.2. In vivo pharmacokinetic study of matrine pellets in beagle dogs: The drug wasmeasured after protein precipitation with acetonitrile mediated sample concentration usingdiazepam as internal standard and ultra-high-performance liquid chromatography-tandemmass spectrometry (LC-MS/MS) for detection. The matrine and diazepam were separated on aShim-pack XR-C8column (2.0mm×100mm,2.2μm) by using a gradient with acetonitrileand ammonium acetate (10mM, pH3.5) as mobile phases at a flow rate of0.3mL·min-1. TheMS/MS detection was done in the positive multiple reaction monitoring (MRM) mode bymonitoring the m/z transitions249.3/148.2for matrine and285.2/193.2for diazepam. Thepharmacokinetics of matrine pellets in beagle dogs was studied by using homemade matrine capsules as reference preparation. The pharmacokinetic parameters were calculated by DAS2.0software.Result1. Preparation of matrine pellets: First, the best formulation of pellets was asfollows:25%matrine,62%MCC,8%octadecanol,5%chitosan,35%ethanol as wettingagent,8%weight gain of octadecanol as gowns and8%weight gain of Eudragit S100ascolonic enteric coating. Secondly, A rapid and effective determination method of matrine wasestablished, the maximum absorption of matrine was200.7nm. The UV method wasvalidated between8and40mg·L-1, the method recovery was92.68%, the repeatability was2.32%. Finally, determination the content of matrine pellets, the average drug entrapment andthe average drug loading was89.98%and22.49%respectively.2. In vivo pharmacokinetic study of matrine pellets in beagle dogs: Plasma concentrationof matrine was determined by LC-MS/MS. The calibration curve for matrine was linear over arange of1~2000μg·L-1with correlation coefficient of0.9984. The inter-and intra-dayprecisions were below9.90%, the extraction recovery of the assay was73.39%-77.68%. Afteran oral single dose of40mg, the Cmaxvalues for matrine pellets (test formulation) and matrinecapsules (reference formulation) were estimated to be of297.25μg·L-1and1168.88μg·L-1,respectively, the Tmaxwere4.62±1.06h and1.22±0.41h, and the MRT(0-t)were7.05±1.95hand2.65±0.75h, respectively.Conclusion The established method of LC-MS/MS with diazepam as internal standarddetermining the concentration of matrine in plasma has the characteristic of strong specificity,high sensitivity and good accuracy. Pharmacokinetic parameters showed that matrine pelletshad a tendency to colon targeting and delayed release effect, and this pellets can be developedas a new formulation for the treatment of ulcerative colitis.