Preparation And Quality Evaluation Of Tetramethylpyrazine Drug Loaded Nanoparticles

Tetramethylpyrazine(TMP)is a kind of alkaloid extracted from Ligusticum chuan-xiongHort.It has many functions,such as protecting cerebral vascular endothelial cells,anti platelet aggregation,and resisting ischemia reperfusion injury.It is mainly applied to cerebral stroke caused by cerebral ischemia.Due to the shortcoming of oral metabo-lism,short duration of drug maintenance and low bioavailability,marketed formulationsh ave greatly limited their clinical applications.In this paper we have studied the prepara tion process of tetramethylpyrazine polybutyl-cyanoacrylate poly(lactideco-glycolide)nan-oparticles and its pharmacokinetics in vivo.Firstly,the methods of in vitro analysis of Tetramethylpyrazine were established,including ultraviolet spectrophotometry and HPLC method.After investigating the nanoparticles prepared by interfacial polycondensation,the encapsulation efficiency of nanoparticles was very low.Therefore,an improved self emulsifying solvent evaporation method and interfacial polycondensation method were developed to prepare tetramethylpyrazine loaded double coated nanoparticles.Separate free TMP and nanoparticles by ultraultracentrifugation and nanoparticles and determine encapsulation efficiency(EE)and drug loading(DL)by HPLC,with the particle size and entrapment efficiency were used to evaluate the influence of different formulation and preparation factors.After the optimization of formulation by orthogonal design L9(34),the optimal formulation was obtained.The quality of TMP-PBCA-PLGA-NPs suspension prepared by the optimal formulation was evaluated.Transmission electron microscope observes TMP-PBCA-PLGA-NPs solid ball structure,round appearance,uniform size,well dispersion,no adhesion.Determination of particle size and distribution of laser particle size analyzer,the mean volume particle diameter was(213.8±8.51)nm,PDI(0.152±0.061),uniform particle size distribution.Zeta potential analyzer for the determination of Zeta potential(-15.36±1.26)mV,the system is more stable.pH to determine the optimal formulation of the three batch of preparations,the average pH is 7.14.Determination of TMP content in the preparation of 10.20 ?g/ml HPLC method,the encapsulation rate was 72.83%,the initial drug loading was 3.37%.The results of investigation of stability,for one month preparation at room temperature appearance,particle size,encapsulation efficiency and drug loading without much change.The release of TMP-PBCA-PLGA-NPs was evaluated by pH7.4 PBS as the release medium.The release rate of the TMP-PBCA-PLGA-NPs was slower than that of the control group.The fitting rate of the drug release curve fitted the Weibull distribution function was the highest,and the release rate was 48 h to 76.23%.HPLC method was established for determination of the content of plasma in femoral vein of rats that were given with the same concentration.The study of pharmacokinetics of laboratory self-made TMP injection and TMP-PBCA-PLGA-NPs in rats.At the same time in 10 min and 60 min were extracted from rat cerebrospinal fluid,determination of its concentration in the two period of drug in the brain,compared the blood concentration and at the same time to observe whether preparation can penetrate the blood-brain barrier function.The blood concentration data of the control group and the preparation group were treated with the noncompartmental analysis.The Results show that TMP nanoparticles solution and the TMP injection were no obvious different in Ke.The TMP injection and TMP nanoparticles solution Cmax were 6865.17±96.58 ng·mL-1,7607.43±257.32 ng·mL-1,AUC(0-t)were 5937.73±101.87 ng·mL-1'·h,9868.39±601.22 ng·mL-1·h,MRT(0-t)were 1.58±0.038 h,2.17±0.071 h.The TMP-PBCA-PLGA-NPs was slow to eliminate in the body,and the retention time was prolonged,and the release effect was presented.The concentration of TMP injection in cerebrospinal fluid of rats in 10 min and 60 min were 4523.70±178.00 ng·mL-1?1575.86±128.29 ng·mL-1;TMP-PBCA-PLGA-NPs in cerebrospinal fluid of rats in 10 min and 60 min were 6313.16±131.33 ng·mL-1?2658.42± 141.43 ng·mL-1.The results showed that the two are a certain concentration in the brain,but the concentration of TMP-PBCA-PLGA-NPs and the blood-brain barrier permeability higher than the TMP injection.