| Tributyrin has a positive effect on maintaining animal intestinal health,improving immunity and preventing inflammation.Because of tributyrin has the special molecular structure of can pass through the cell membrane of some bacteria,inhibit the growth and cell division of bacteria,but also promote the apoptosis of cancer cells and affect the regulation of cell cycle.Tributyrin is widely used as a feed additive in the feed industry.The nanostructured lipid carriers(NLC)is mainly used to embed the active substance with the lipid material to prevent the active substance from being destroyed by the environment(temperature,oxygen,pH,enzyme,etc.),thereby improving the biological activity and utilization of the active substance.The nanostructured lipid carrier has the advantages of targeting,no toxicity,no immunogenicity and so on,and has the advantages of high bioavailability,convenient absorption and high stability.The tributyrin-loaded nanostructured lipid carriers(TB-NLC)were prepared by thin film dispersion method using phospholipid and glycol decanoic acid succinic acid monoester as solid lipid,using tributyrin as liquid lipid and embedding drug and ethanol as solvent.The The optimum preparation process of tributyrin-loaded nanostructured lipid carriers was determined by single factor and orthogonal test.According to the experimental equipment and process conditions,a better production process conditions for the PC added amount of 120 mg,glycol decanoic acid succinic acid monoester addition of 80 mg,tributyrin addition of 35 mg,PBS buffer pH 7.4(50ml),Anhydrous ethanol 8ml,ultrasonic time 4min.The average size of NLC was 113.3 ± 2.1 nm,zeta potential was-31.7 ± 3.2 mV,and the PDI was 0.273.The encapsulation efficiency of tributyrin was 84.95% under the basis of the optimum preparation process.Through transmission electron microscopy analysis,the tributyrin-loaded nanostructured lipid carriers were dispersed evenly,with moderate size and good dispersibility.The tributyrin-loaded nanostructured lipid carriers of prepare under the optimal conditions were added to the simulated intestinal fluid for sustained release and the release in the intestinal fluid were measured.The results showed that the cumulative release rate of TB-NLC reached 17.5% at 30 min,and the results showed that the release rate of TB-NLC was 17.5% at 30 min,and the results showed that the release rate of TB-NLC was 17.5%,60 min cumulative release rate of 21.6%,at 210 min reached 50.2% and then the cumulative release rate changes slowly,at 300 min when the cumulative release rate of only 54.3%,played a role in slow release.In order to preserve the NLC better for a long time,the stability of NLC at 4? and 25? was investigated,and its size,zeta potential and size under TEM were compared.The result was NLC at 4? thermostats is more conducive to storage.The tributyrin proliposomes were prepared by spray-drying method and freeze-drying method.The protective agents glucose,sucrose and lactose used in each preparation method were screened to prepare the better tributyrin proliposomes.It was best to use lactose as protection agent when tributyrin proliposomes were prepared use spray-drying process,and tributyrin proliposomes were many advantages,such as high stability,weaker absorbent,easily saved and easily rehydration.The particle size of tributyrin nanoiposomes after rehydration was 151.3nm,and the zeta potential was-25.5mV.The tributyrin proliposomes were prepared by freeze-drying method,the best use of lactose to do the protective agent,the preparation of the tributyrin proliposomes were uniform color,uniform surface density,no shrinkage phenomenon,stable and easy to save,best effect,and rehydration easily.The particle size of tributyrin-loaded nanostructured lipid carriers after rehydration was 145.2 nm,and the zeta potential was-37.5mV.Based on the preparation of tributyrin-loaded nanostructured lipid carriers,the corresponding degree of amplification test was carried out to further study the corresponding influencing factors.Under the condition that the ultrasonic equipment and parameters were unchanged,the length of ultrasound time has an effect on the size of the tributyrin-loaded nanostructured lipid carriers.Therefore,the ultrasonic time should be prolonged accordingly,when the preparation process of the tributyrin-loaded nanostructured lipid carriers is enlarged.The average encapsulation efficiency of tributyrin in the tributyrin-loaded nanostructured lipid carriers was 85.2%.For the stability of the tributyrin-loaded nanostructured lipid carriers at different magnifications,the changes of zeta potential of the tributyrin-loaded nanostructured lipid carriers of 2-10 times were slow and the average rate of change was 8.6% and 13.5% for 10 days and 50 days,respectively.During the 10 days storage,the particle size of the tributyrin-loaded nanostructured lipid carriers tends to be stable in 10 days.After 50 days of storage,the average of the particle size increased from 176.7 nm to 299.6 nm and the particle size growth rate was 69.5% for 2,4,6,8 and 10 times magnification.The aggregation of the tributyrin-loaded nanostructured lipid carriers in the system formed of different particles,the overall stability is poor.For the preparation process of different magnification,TEM analysis was found that the size of the tributyrin-loaded nanostructured lipid carriers was 100 ~ 200 nm,the size was uniform,rounded,and the mutual;there is good dispersion,more stable and no adhesion.The antibacterial activity of three kinds of bacteria,such as Escherichia coli,Staphylococcus aureus and Bacillus subtilis,was tested.The results showed that the tributyrin-loaded nanostructured lipid carriers had antibacterial properties,and the longer the time,the more obvious of the antibacterial activity.For the addition of different amounts of tributyrin-loaded nanostructured lipid carriers,the culture medium supplemented with 20 ml of tributyrin-loaded nanostructured lipid carriers had a great effect on the growth of bacteria,and the antimicrobial effect of tributyrin was the best. |
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