| The solubility of the drugs,such as apigenin,dihydromyricetin,curcumin were very poor,which limited the practical application.In recent years,liquid crystals,microemulsions and vesicles can be used as drug carriers for solubilizing drugs,which have sustained and controlled release effect on drugs?such as apigenin,dihydromyricetin,curcumin?.In this paper,the microemulsions was chosen as the drug carrier and characterized by dynamic light scattering?DLS?and infrared spectrum?FTIR?.Then the antioxidant activity and in vitro release behavior of drugs from the microemulsions were further explored.The contents of this paper included four parts which were listed as follows:?1?In the early stage,the articles about the microemulsions were read and its application in the field of the food,medicine and materials preparation were elaborated.Due to the low toxicity and degradation easily of the biocompatible microemulsions,it were widely concerned by the researchers in the recent years.Then the literatures of the biocompatible microemulsions were read.The articles about the usage of the microemulsions as the drug delivery in the field of medicine were further reviewed.On the base of these literatures,different type of microemulsions?O/W,W/O,B.C.microemulsions?were chosen to encapsulated the drugs,such as apigenin,dihydromyricetin,curcumin and tea polyphenols.Then the antioxidant activity and the in vitro release behavior of drugs in the biocompatible microemulsions were further studied.?2?In this chapter,the peudo-ternary phase behavior of Tween 80/geraniol/1,2-propylene glycol?PEG 400 or glycerol?/H2O has been studied.The O/W microemulsions were chosen as the carrier of apigenin,which improved the solubility of apigenin about 240-290 times?compared with the solubility of apigenin in aqueous solution?.Compared with the release of apigenin from the ethanol solution,the bicontinuous microemulsions and O/W microemulsions had an sustain effect on the apigenin.Maybe the interfacial membrane of the microemulsions with 1,2-propylene glycol was more flexibility,which has the maximal cumulative release rate,cumulative release and antioxidant activity?ABTS·+?.With decreasing the mass ratio of the Tween 80 and oil,the microemulsions droplet swelled and the particle size increased,which caused the maximal cumulative release rate and antioxidant activity increased.The cumulative release rate and antioxidant activity of apigenin decreased in the bicontinuous region compared with that in the O/W region,which maybe that the intermolecular interaction of bicontinuous microemulsions was higher than the O/W region.The release kinetics showed that the release of apigenin from the microemulsions basically accorded with first-order kinetics,which demonstrated that the release of apigenin was mainly controlled by concentration diffusion.Based on the previously study of Brij97/isopropyl alcohol/isoamyl acetate?or ethyl acetate?/H2O system,the O/W microemulsions was selected to encapsulated the curcumin.With the decreasing in Km?the mass ratio of Brij 97 and isopropyl alcohol?,the particle size increased and the hydrogen bond strength increased,which caused the antioxidant activity decreased.With increasing the temperature,the particle size of the O/W microemulsions increased.The antioxidant activity increased firstly and then decreased at 45 oC.With the mass ratio of the EM?Brij 97 and isopropyl alcohol?and oil decreasing,the particle size of the microemulsions increased and the droplet swelled,which caused the antioxidant activity increased.These studies indicated that the O/W microemulsions can be used as an excellent carrier for the drug of apigenin or curcumin.?3?In this chapter,based on the previous work of our lab,the biocontinuous microemulsions system of S1570/NaDC/isopropyl alcohol/isoamyl acetate/NaCl were chosen to encapsulating apigenin and the biocontinuous microemulsions of the S1570/NaDC/isopropyl alcohol/IPM/H2O system were chosen to encapsulating dihydromyricetin.The results showed that the microemulsions improved the solubility of the two kinds of the drug and had a sustained release effect on microemulsions.Apigenin still has good antioxidant activity in microemulsions.With the mass ratio of the S1570 and NaDC,NaCl concentration increased and the chain length of the oil phase molecular decreased,the cumulative release rate and antioxidant activity?the scavenging activity of the ABTS·+?of the apigenin in the sample increased.The introduction of VC accelerated the release of apigenin and increased the antioxidant activity of apigenin.The antioxidant activity and cumulative release rate of the dihydromyricetin in the S1570/NaDC/isopropyl alcohol/IPM/H2O system increased with increasing the mass ratio of the emulsifier?S1570,NaDC and isopropyl alcohol?/IPM and water content.With increasing of the pH,the rate of release was accelerated.With increasing the temperature,the cumulative release rate of the dihydromyricetin decreased.The release curve of the drug in the microemulsions were more consistent with the first order kinetic equation,which showed that the release of drugs in microemulsions was mainly controlled by the concentration diffusion.The results showed that the bicontinuous microemulsions based on the surfactant of S1570 and NaDC could be used as a carrier of the apigenin or dihydromyricetin.?4?Firstly,the phase behavior of the Tween 80/IPM/H2O system in 25 oC was studied.The samples with high oil content and the transparent appearance were chosen to encapsulated the tea polyphenols.Microemulsions was measured by size and studied by infrared spectrum?FTIR?.Then the several samples from the hexagonal liquid crystal regions were selected to solubilize the dihydromyricetin.It was found that the introduction of chitosan reduced the ability of the system to form aggregation.The results showed that with increasing the chitosan content and the water content,the mass ratio of surfactant/oil decreased,the release rate and the cumulative release rate decreased.The decreasing of pH accelerated the cumulative release rate of the dihydromyricetin. |
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