| Lithospermum is a dry root of the borage family Arnebiaeuchroma(Royle)Johnst or Arnebiaguttata Bunge.It was originally contained in the Shennongboshi Classic.It is bitter,cold,and has detoxification,rash,cooling,and blood circulation effects.Lithospermum has a wide range of clinical applications,especially for various skin injuries,including trauma,burns,scalds,skin sores,inflammation,eczema,acne,and so on.Shikonin is the main medicinal component of Lithospermum erythrorhos;it is a fat-soluble napHthoquinone compound with poor water-solubility.It is easily decomposed by light,and is extremely sensitive to pH and unstable under alkaline conditions.It is seriously affects the quality stability of Lithospermum preparations and clinical efficacy.After microencapsulation of drugs,not only can effectively avoid the influence of the external environment,improve drug stability;while particle size at 100-300 nm is conducive to increase the residence time of drugs in the skin and improve skin targeting.In order to improve the stability and skin-targeting of shikonin,we has studied the preparation technology of Lithospermum microcapsules.In order to facilitate clinical use,Lithospermum erythrorhizon is further prepared into a gel preparation.As a new type of skin external preparation,the gelling agent has the characteristics of good compatibility with the skin,easy application,easy cleaning,and not easy to contaminate the clothes.The main research contents and results of this topic are as follows:1.Preparation of prescription drugsEthanol extraction was used to extract the active components from Lithospermum erythrorhizon.The prescription drugs were purified by acid-base precipitation and its quality was evaluated.The content of total napHthoquinone in the prescription drug was determined by UV method,and the established method was investigated.The total napHthoquinone content in the prescription drug was 86.19%.The content of shikonin in the prescription drug was determined by HPLC method.The established method was used for the methodological investigation.The shikonin content in the prescription drug was 84.96%.The higher content of shikonin in prescription drugs can provide raw materials for formulation and pHarmacological research;the established detection method is accurate and simple,and can provide a reliable detection method for the determination of microcapsules.and can provide a reliable detection method for the determination of microcapsules.2.Preparation of Lithospermum MicrocapsulesThis topic selects the complex agglutination method to prepare the lithospermum microcapsules based on the properties of shikonin and skin compatibility.We examined the key steps in the preparation process that affect the properties of the microcapsules and optimized the preparation process parameters.(1)The effect of the shear rate,the type of emulsifier,the temperature,the amount of addition,and the dilution of water added on the emulsification effect was examined by a single factor test.The results show that when the shear rate is 10000 r/min,the emulsification effect is the best;the type of emulsifier will affect the emulsification effect;the emulsification effect of Tween and Span is better;the emulsification temperature,the amount of emulsifier added,and the dilution of water added Emulsification has a significant effect.On the basis of single-factor tests,the average particle diameter of the emulsion and PDI were used as indices to design the L9(34)orthogonal test,and the optimal emulsification scheme was selected.The results show that the four factors of the type of emulsifier,temperature,and dilution of water added will affect the size of the emulsion particle size,the amount of emulsifier will affect the PDI of the emulsion;the best emulsification scheme is:the emulsifier is Tween:Span(1:1),emulsification temperature is 55℃,emulsifier is added 0.5%of oil pHase,dilution ratio of water is 6 times;verify the best emulsification scheme,the average particle size of emulsion is 237nm,PDI 0.420,indicating that the method is stable and feasible.(2)Taking the effective utilization rate of wall materials as the inspection index,the key parameters for the preparation of comfrey microcapsules by the complex coagulation method such as gelatin isoelectric point,optimal recombination pH,gelatin and sodium alginate ratio were studied.The results showed that the isoelectric point of gelatin was 4.6;when the pH was 4.0-4.2,gelatin had the most positive charge and could be used as the optimal pH for re-aggregation;when the ratio of gelatin and sodium alginate was 5:1,both walls Material can be combined completely.(3)The encapsulation efficiency and the microcapsule structure were used as the inspection indexes to compare the effects of tannic acid and calcium chloride as curing agents on the preparation process of microcapsules.The test results showed that when tannic acid was used as a curing agent,the encapsulation efficiency of the microcapsules is higher,and the microcapsules are smoother,and can wrap the lithospermone completely,which is more suitable as a curing agent for the comfrey microcapsules.(4)On the basis of single-factor tests,factors such as concentration of wall material,ratio of core to wall and concentration of curing agent,which affect the microencapsulation efficiency and the microcapsule size were selected.Box-Behnken experimental design method was used to optimize the preparation process of Lithospermum microcapsules with the encapsulation efficiency and average particle size as the inspection indexes.Finally,the best preparation process for the microcapsules as floows:the concentration of wall material is 1.5%,the ratio of core and wall is 1.96,and the concentration of curing agent is 0.44%.The encapsulation efficiency was measured to be 90.93%,the particle size was approximately 245 nm,and the PDI was 0.391.The capsules have a regular spHerical shape and a smooth surface,which can provide stable quality comfrey microcapsules for further study.3.Preparation and Quality Evaluation of Lithospermum Microcapsule GelIn order to better exert the curative effect of lithospermum,lithospermum microcapsule gel was prepared.Firstly,the effects of carbomer content,glycerol content,and gel pH on the gel preparation were investigated by single factor test.The results showed that there were three factors.Has a significant effect on the formation of the gel.On the basis of single-factor tests,the optimal preparation process of Lithospermum microcapsule gel was optimized by L9(34)orthogonal experiment.the Carbomer content(A),glycerin content(B)and gel pH(C)as process optimization parameters,comprehensive evaluation of gel homogeneity,gloss,spreadability,centrifugality,and heat and cold resistance as process optimization indicator.The results showed that the optimum preparation process of Lithospermum umbellata microcapsule gel was 0.5%for Carbopol,15%for glycerin,and 6.5 for pH.The gel prepared was uniform and glossy,and its spreadability was very good.And after heat and cold resistance and centrifugal test,the gel is still stable,without delamination and denaturation. |
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