Preparation,Characterization And Activity Evaluation Of Lutein Esters Submicron Powder Using Anti-Solvent Precipitation Technology

Lutein Esters,an important carotenoid fatty acid ester,is a natural substance widely found in plants such as marigold.The structure of it is predominantly all-trans configuration with C ＝C chromophore,showing a bright golden colour of yellow.Lutein esters can be transformed into lutein through metabolism and hydrolysis inside the body.Besides,this kind of lutein can effectively absorb the blue light which can cause damage to the human retina.It can also prevent cataract,senile macular degeneration,cardiovascular disease and cancer.In addition,lutein esters also have antioxidant,anti-aging activities and improve immunity and so on.Lutein esters,as a pure natural ingredients extracted from plants,has a strong coloring effect,which may replace the chemical colorants used in beverage,food and cosmetics.If so,it is more conducive to human health.However,its low aqueous solubility result in low bioavailability,which is a major obstacle for its wide applications.In the present study,the liquid antisolvent precipitation method was developed for the preparation of Lutein esters submicron powder.The micro powder have small diameter andgreat surface area,which is meaningful to its solubility and bioavailability.The solvent(tetrahydrofuran)and antisolvent(water)was confirmed based on the saturated solubility of lutein esters in various common solvents.Then the drug concentration,the surfactantdosage of poloxamer 188,the proportion of tetrahydrofuran and water,stirring speed,reaction temperature,stirring time were determined by single factor optimization experiment method.The optimal conditions for preparation of Lutein esters submicron powder using anti-solvent deposition method were screened by the criterion of measuring the size of particles.And then the physical and chemical properties,solvent residue,drug content,saturated solubility,dissolution rate,antioxidant ability in vitro,antioxidative ability in rat tissues,bioavailability of rats in vivo and nanomedicine distribution in rat tissues of Lutein esters submicron powder were studied in this paper.The results are as follows.1.The preparation technology of nanoparticles preparation was optimized using single factor experiment.The optimized preparation conditions were as follows:10 min of stirring time,2.5 mg/mL of Lutein Esters concentration,1:7 of the volume ratio of solvent to antisolvent,0.5%of the poloxamer 188 mass fraction,950 r/min of stirring speed,25 ℃ of reaction temperature.The particle size of Lutein esters submicron powder freeze-dried powder obtained under the optimal conditions is 160nm after redissolving in water,and the content of lutein esters is 38.9%.2.The results of physical and chemical properties of Lutein esters submicron powder were as follows.SEM images can be seen,the nanoparticles were nearly spherical with uniform size.The X-ray diffraction(XRD)thermogravimetric analysis,thermogravimetric analysis(TGA)and differential scanning calorimetry(DSC)results showed that Lutein esters submicron powder compared to raw powder had lower crystallinity,and mangly in amorphous state.3.The solvent residue experimental results showed that tetrahydrofuran residue content in Lutein esters submicron powder was 344.3 ppm,which was in accordance with the minimum standard(780 ppm)required by the International Harmonized Register of Technical Requirements for Registration of Human Drugs(ICH).4.Antioxidant experiment results were as follows:the antioxidant capacity of Lutein esters submicron powder were significantly higher than that of the original drug and the capacity increased with increasing concentration.The scavenging rate of DPPH free radicals was 3.13 times higher than the original drug and the scavenging rate of ABTS radicals reached 3.93 times at same condition.Furthermore,the reducing power of nanoparticles was 5.4 times higher than control.5.Saturation solubility experiment and dissolution study showed that the saturated solubility of the Lutein esters submicron powder was significantly higher than raw powder and the saturated solubility was 124.35 μg/mL and 42.75 μg/mL,respectively.The saturated solubility of the lutein ester nanoparticles was 2.91 times of that of the original drug.The results of dissolution rate experiment in vitro showed that the dissolution rate of Lutein esters submicron powder was about 9.65 times of raw powder in 2 hours and the dissolution rate was 31.28%and 3.24%.6.The oral bioavailability experiment of Lutein esters submicron powder and origi nal drug showed that the content of Lutein esters submicron powder in the plasma of t he mice was higher than original powder.The maximal content of lutein in the plasma of the experimental group was 15 min after the intragastric administration,and the co ncentrate was 4.71 μg/mL.But the content of lutein in the plasma of the original drug appeared at 2 h,the maximum content was 1.87 μg/mL.According to the pharmacoki netic analysis,the bioavailability of Lutein esters submicron powder was 1.41 times t han raw powder.7.The tissue distribution experimental results of Lutein esters submicron powder in rats showed that nanoparticles distribution is much larger than raw powder in main organizations at different time points.The distribution of drugs in the liver is the highest,this is because in addition to the liver is the blood of the most intensive areas,and is also a major metabolic organs.From the above experiment results,the Lutein esters submicron powder prepared in this research had small particle size,uniform particle size distribution and alsolow solvent residual.The prepared Lutein esters submicron powder can not only enhance its solubility and antioxidant activity,but also improve its bioavailability and increase the drug content in each organ.