The Preparation, In Vitro Evaluation And Transdermal Mechanism Of Matrine Total Alkali Nanoemulsion Gel

Objective:Prepare Sophora flavescens alkaloids(SFA)nanoemulsion-based gels(NBGs)with SFA as model drug,which applied to treat acute eczema and subacute eczema.Optimize the preparation technology of SFA NBGs and evaluate its in vitro characterization and quality.Investigate percutaneous permeability in vitro of SFA NBGs and illuminate its mechanism of transdermal delivery basically.Methods:In preliminary studies,establish HPLC assay to measure oxymatrine(OMT)and matrine(MAT)simultaneously and research methodology.With the solubility of SFA and emulsifying capacity as evaluation index,chose oil phase,surfactant and co-surfactant.The composition and proportion of the nanoemulsion(NE)were further screened by pseudo-ternary phase diagram method and CCD-RSM.The optimal drug loading capacity was determined by cumulative permeated amount per cm2 of OMT and MAT.Secondly,discriminate the type of NE by staining method and dilution method,and investigate its physicochemical properties of morphology,diameter,viscosity and pH and stability.The entrapment efficiency of NE was determined by ultrafiltration-centrifugation method.Establish in vitro transdermal experimental methodology of OMT and MAT,and research the skin penetration of NE.Thirdly,the type and amount of NBGs matrix were screened by synthesizing multiple guidelines grading method,and the preparation was optimized.Afterwards,study the physicochemical properties,such as,character,morphology,diameter,viscosity and so on,and stability under high temperature and high humidity.Meanwhile,compare in vitro transdermal performance of different system of SFA.Use tape stripping to peel stratum corneum(SC),and contrast skin penetration and skin retention of SFA NE and SFA NBGs in whole skin and skin without SC.At last,investigate the effect of SFA NE and SFA NBGs on SC and ultrastructure,which could illuminate tentatively their transdermal mechanism.Results:The established methodology of measuring OMT and MAT simultaneously was in line with requirements.The optimal composition and proportion of SFA NE was,oil phase:surfactant:co-surfactant:SFA:water=0.09:1.73:1.36:0.1:6.72.SFA NE was O/W type,round morphology,uniform sphere,moderate diameter,and was Newtonian fluid.The stabilities after centrifugation and under 4?,25?,60? for 15 days were good,and the mean entrapment efficiency was 82.15%.The methodology of transdermal experiment in vitro of OMT and MAT met requirements,and the cumulative permeation amount per area(Qn)and steady state permeation rate(Js)of SFANE were higher than water solution.With NP 700 and CP-9334 by the mass ratio of 0.4:0.25 as SFA NBGs matrix,the NBGs performances round and uniform sphere,suitable diameter and was non-Newtonian fluid.The Qn and Js of SFA NE were the most optimal,while the hydrogels and water solution were poorer.The Qn and Js of NE physical mixture were relatively closed to NBGs,but weaker than NBGs while higher than O/W type cream.The SC of SD rat could be completely peeled for 30 times by tape stripping.In the in vitro transdermal experiment without SC,the Js of SFA NE and SFA NBGs were respectively 4.72 times and 4.58times as in whole skin transdermal experiment.Simultaneously,the drug skin retention of NE and NBGs were 1.49 times and 1.51 times compared to the whole skin.The result of scanning electron microscopy showed,the SC of normal mouse was smooth and finishing,after treatment 6h by saline,it appeared slightly crimp,while it was damaged in varying degrees after action 2h and 6h by NE and NBGs respectively,and NE was stronger than NBGs.HE staining found that the skin structure of saline group was basically intact,hierarchy was clear.But the hierarchy structure of NBGs group was not obvious,basal layer arranged unclearly and SC loosed apparently,as well as that the hierarchy structure of NE group disordered,the gap increased,SC loosed and thinned.The result of confocal laser scanning microscopy indicated,fluorescence in surface was stronger while weaker in depth among control group,NE group and NBGs group,and fluorescence in hair follicles and around its appendages was also stronger,then fluorescence of control group was weaker than NE group and NBGs group.Conclusion:SFA NE of we prepared has high drug loading capacity and entrapment efficiency,round and uniform morphology,smaller particle size,good stability and skin penetration.While the viscosity of SFA NBGs is moderate,its adhesion and spreadability with skin are good,and its transdermal performance and penetration amount are superior to other SFA system.SFA NE and SFA NBGs could permeate skin mainly through breaking SC and ultrastructure so as to performance therapeutic action.At the same time,hair follicles and its appendages play a role on drug transdermal course.Therefore,SFA NBGs has good feasibility on treating acute and sub-acute eczema by transdermal delivery,and can provide a new method and technology for other transdermal therapeutic system.