| Stroke has obvious "four high" characteristics,namely high incidence,morbidity,recurrence rate and mortality,which is a great threat to human health.Due to the presence of the blood-brain barrier(BBB),the drug by the oral and intravenous route is difficult to be absorbed into the brain,which greatly limits the effective treatment of brain diseases.Nasal administration for the treatment of brain diseases has obvious advantages,such as rapid onset,brain targeting,good bioavailability and ease of use.Salvianolic acid B(SalB)is an important active ingredient of Salvia miltiorrhiza,with pharmacological effects of improving blood supply to the brain,protecting the brain and anti-platelet aggregation,is the main component of the injection salvianolate.However,due to poor compatibility between SalB and mucosa,low oral bioavailability,targeting poor brain,study find in rats after intravenous injection SalB using of LC-MS/MS SalB in the brain is not detected;and because of its molecular structure contains no unsaturated double bonds and phenolic hydroxyl groups,SalB is susceptible to light,temperature,pH and other factors and to be degraded,which to some extent affected the efficacy of SalB.SalB improve brain targeted by means of pharmaceutics,which will play an important role to the treatment of brain diseases.Liquid crystal nanoparticles(LCN)is a nano-dispersion system of amphiphilic lipids and water spontaneous formation of cubic closed lipid bilayer,similar to biological membranes.LCN has good affinity with biofilm,and can promote the absorption of the drug;can encapsulate different polarity drugs,improve the stability of the drug;also has good bioadhesive,biodegradable,safety and other characteristics,is a kinds of potential drug carrier systems.In order to improve SalB absorption in the nasal cavity and brain,the subject prepared SalB liquid cubic crystal nanoparticles(SalB-LCN),to optimize the preparation process of SalB-LCN,and to study its pharmaceutical properties,and cross-absorption across the nasal mucosa and BBB,specific contents are as follows:1.Preparation and characterization of pharmaceutics of SalB-LCNEstablished method for the determination SalB of SalB-LCN.Select to ultrafiltration to measure the encapsulation efficiency Sal B of SalB-LCN(UF pre-saturation).On this basis,choose the simple injection method,using more common A/B/water system prepared SalB-LCN,through single factor test by encapsulation efficiency the preparation process was optimized,including the stirring speed,stirring time,ultrasonic power,ultrasonic total continuous time,each ultrasonic continuous time and ultrasound pause time,determined SalB-LCN optimum process parameters.By single factor and orthogonal experiment design,encapsulation efficiency and drug loading as the index,prescription of SalB-LCN is optimized,finally obtained SalB-LCN encapsulation efficiency was 74.89 ? 0.78%,drug loading was 4.13 ± 0.11%.Through TEM,laser particle size analyzer,X-ray diffraction,measured SalB-LCN of milky white appearance is cubic morphology,having an average particle diameter of 216.1±0.9 nm,the average potential of-16.2±0.8 mV,"Cubic" cubic crystal structure,good dispersion,stable state.2.Absorption of circulation in the body nose of SalB and SalB-LCNIn order to evaluate SalB cubic crystal nano drug delivery systems capabilities across the human nasal cells,this experiment use the nasal cycle perfusion model in rats in vivo,study the nasal absorption process of SalB and SalB-LCN,compare the nasal absorption rate of SalB and SalB-LCN.In order to reduce the liquid nasal irritation,in the subject by the total protein and LDH release as an indicator,the SalB buffer pH were screened,the results show that the size of the order of irritating pH4>pH5>pH6>saline.Since the pH has a great influence on SalB stability,study the stability of SalB within the next 24 h 37? water bath conditions in different pH of nasal perfusate.The results show SalB is unstable in pH6.0.Final selection buffer pH 5.0,drugs under the condition have small mucosal irritation and high drug stability.Under conditions of pH5.0,to SalB and SalB-LCN performed in situ nasal perfusion experiments.The results showed that:low,medium,high concentrations of SalB absorption rate constant K was no significant difference,indicating that the nasal absorption of SalB first order absorption model,suggesting that the mechanism of absorption is passive diffusion based on the concentration gradient of the quality.In 400?g·mL-1 concentrations,SalB SalB-LCN and K values were 1.64×10-3 min-1 and 3.75×10-3 min-1,the nasal absorption rate of 19%and 34%,respectively,the two groups have significant differences.Visible cubic crystal nano-drug delivery system can enhance mucosal permeation rate of SalB,it has the effect of promoting nasal absorption of drugs.3.BBB MDCK-MDR1 cells Absorption of SalB and SalB-LCNIn order to evaluate SalB-LCN through the human blood-brain barrier cell capacity,this study,in vitro BBB MDCK-MDR1 cell model Cubic crystal nano drug delivery systems in transit BBB measured SalB and SalB-LCN through rate.First,the establishment of a more stable MDCK-MDR1 cells were cultured and passaged methods.By MTT assay conducted experimental study drug toxicity,determine dose safety.Two selected non-cytotoxic concentration of 60?g·mL-1 transport for experimental study.Study and compare the cell membrane transport processes SalB and SalB-LCN's.The results showed that:SalB absorbed on MDCK-MDR1 cell monolayer model and Papp efflux rate is less than 1×10-6cm·s-1,while less than 2 efflux rate Re,suggesting SalB difficult through the blood MDCK-MDR1 cell model,suggesting that bypass SalB by cell transport and absorption.SalB-LCN compared with SalB,uptake and efflux rates were increased by 69%and 56%,with a significant difference,indicating that the cubic crystal nano drug delivery system can promote the absorption of SalB brain.Speculate SalB-LCN by endocytosis and cell adhesion and promote the role of SalB absorption and improve its ability to cross the blood brain barrier. |
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