| Curcumin(CUR),a kind of natural effective component,is abstract from rhizoma of Curcuma L.,such as curcuma,zedoary,turmeric etc.It has many kinds of pharmacological action and the important economic value including anti-inflammatory,anti-tumor,anti-hiv,antibacterial,antioxidant,protecting liver and kidney.It has low toxicity and become a hotspot of development,which has good clinical application potential.However,curcumin has defects of low water solubility and bioavailability.Nanosized curcumin can improve the solubility of curcumin in the water,accompanied by improving the absorption and bioavailability of curcumin,resulting in reducing the dose and save resources.Meanwhile,targeting effect enhancement of curcumin makes curcumin with slow release and controlled release properties and pass through physiological barrier.So it changes the traditional dosage forms of curcumin,enriches dosage form and administration route of curcumin and improve its stability.In the research,curcumin nanoparticles were prepared by liquid phase precipitation method.A total of 10 factors including drug concentration,Tween 80,the proportion of water and organic phase,drug dropping speed,stirring speed,stirring time,reaction temperature,homogeneous pressure(HP)and homogeneous times,the mass ratio of curcumin and mannitol were investigated by single factor optimization experiment method and the optimized conditions were selected.And the physical and chemical properties,drug content,solvent residue,dissolution rate,equilibrium solubility,antioxidant ability in vitro,antioxidative ability in rat tissues,bioavailability of rats in vivo and nanomedicine distribution in rat tissues of curcumin nanoparticles were studied.The results are as follows.1.The preparation technology of curcumin nanoparticles preparation was optimized using single factor experiment.The optimized preparation conditions were as follows:8mg/mL of curcumin concentration,0.5mg/mL of Tween 80 concentration,5:1 of the proportion of water and organic phase,3mL/min of drug dropping speed,500r/min of stirring speed,5minof stirring time,0℃ of reaction temperature,50MPa of homogeneous pressure(HP)and 7 times of homogeneous times,1:4 of the mass ratio of curcumin and mannitol.The particle size of curcumin nanoparticles freeze-dried powder obtained under the optimal conditions was 91.2nm after redissolving in water,the content of curcumin is 15.30%.2.The results of physical and chemical properties of curcumin nanoparticles were as follows.SEM images can be seen,the granule morphology of raw curcumin powder was larger particles flake,however the particle size of curcumin nanoparticles obviously decreased and its granule morphology was irregular and uniform block by scanning electron microscope.In addition,the fourier transform infrared spectroscopy(FTIR)and the liquid chromatography mass spectrum(LC-MS)results showed that the chemical structure of the curcumin nanoparticles cannot be changed but only its physical properties changed.The X-ray diffraction(XRD)and differential scanning calorimetry(DSC)results showed that curcumin had lower crystallinity,lower melting point and was amorphous.TGA(thermogravimetric analysis,TGA)detection result,nanoparticles tended to have faster evaporation and thermal decomposition,which may due to curcumin nanoparticles had smaller particle size and larger specific surface area than raw powder and mixture.3.The solvent residue experimental results showed that acetone residue content in curcumin nanoparticles was 14ppm or 0.0014%.Residual solvent class 3-acetone is 5000 PPM or 0.5%according to ICH.So acetone residue content in curcumin nanoparticles was in accordance with ICH and could be used as a kind of drug.The content of Tween-80 of curcumin nanoparticles was 0.25%,and as a kind of pharmaceutical excipients,the dosage of Tween-80 in the Chinese pharmacopoeia(CP 2005)was stipulated and cannot exceed 1%to 2%,the results showed that the Tween-80 content of curcumin nanoparticles was in accordance with the China pharmacopoeia(CP 2005)standard.4.The drug stability test results showed that the average particle size and the content of curcumin nanoparticles were basically unchanged during the curcumin nanoparticles placing in 25℃ for 12 months,which demonstrated the curcumin nanoparticles did not generate the aggregation and adhesion phenomenon during the storage period.Meanwhile,from the looks of the curcumin nanoparticles,its colour was unchanged and its lustre was uniform,no collapse or drying shrinkage phenomenon.After dissolved with water,the whole system was uniform and stable.5.Saturation solubility experiment results showed that the saturation solubility of curcumin nanoparticles was much larger than raw curcumin powder.The saturated solubility of raw curcumin powder and curcumin nanoparticles in water is 15.44 and 636.36p,g/mL,respectively.The saturated solubility of nanometer powder is 41.2 times of raw powder.The saturated solubility of raw curcumin powder and curcumin nanoparticles in simulated gastric fluid are 52.30 and 91.23μg/mL,respectively.The saturated solubility of nanometer powder is 1.74 times of raw powder.The saturated solubility of raw curcumin powder and curcumin nanoparticles in simulated intestinal fluid is 1.47 and 22.48μg/mL,respectively.The saturated solubility of nanometer powder is 15.29 times of raw powder.6.The results of dissolution rate experiment in vitro showed that curcumin nanoparticles had a faster dissolution rate than raw curcumin powder.From the results of the dissolution experiment in water,in the 30 min,the dissolution rate of curcumin nanoparticles is about 14.51 times of raw curcumin powder;in the 90 min,,the dissolution of both are close to balance,the dissolution rate of curcumin nanoparticles powder is about 21.11 times of raw curcumin powder.From the results of the dissolution experiment in artificial gastric juice,the dissolution rate of curcumin nanoparticles is about 2.5 times of raw curcumin powder;in the 90 min,the dissolution of both are close to balance,the dissolution rate of curcumin nanoparticles powder is about 2.33 times of raw curcumin powder.From the results of the dissolution experiment in the artificial intestinal juice,in the 30 min,the dissolution rate of curcumin nanoparticles is about 57.36 times of raw curcumin powder;in the 90 min,the dissolution of both are close to balance,the dissolution rate of curcumin nanoparticles powder is about 44.79 times of raw curcumin powder.The curcumin nanoparticles can play a better effect in a short time.7.Antioxidant experiment results in vitro showed IC50 value of DPPH radical scavenging ability on curcumin nanoparticles and raw curcumin powder was 0.03857 mg/mL and 0.13487 mg/mL,respectively.IC50 value of ABTS radical scavenging ability on curcumin nanoparticles and raw curcumin powder was 1.54665 mg/mL and0.00287 mg/mL,respectively.When the concentration of drug was 1 mg/mL,reducing power value of curcumin nanoparticles was 2.18,while reducing power value of raw curcumin powder was 0.014.DPPH radical scavenging ability,ABTS radical scavenging ability and potassium ferricyanide reducing power of curcumin nanoparticles was enhanced obviously,which indicated that the process of nanoparticles prepared by liquid precipitation improved the drawbacks of poor water solubility,enhancing the antioxidant ability of curcumin.8.The antioxidative ability tests in rat tissues indicated that super oxide dismutase(SOD)activity,catalase(CAT)activity,glutathion peroxidase(GSH-Px)activity and malonaldehyde(MDA)value of curcumin nanoparticles were all larger than raw curcumin powder under the condition of the same administration dose and surroundings and the results of 28 days later of dose lavage were better than 14 days later.The results were obtained in blood serum through 0 days,14 days and 28 days later of dose lavage of 100mg/kg,300mg/kg,500mg/kg of dose lavage.This illustrated the curcumin nanoparticles had stronger ability to resistant the membrane lipid peroxidation and eliminate free radicals in the serum.Reducing the particle size of curcumin could improve the activity in vivo effectively and release better.So it showed stronger antioxidant activity in vivo.9.The oral bioavailability experiment of rats experiment results on curcumin showed curcumin powder and curcumin nanoparticles in mice reached the 1.2ng/mL and 2.5ng/mL of the highest drug plasma concentration after 1.5 h of dose lavage.Through comparing the corresponding AUC values,the oral bioavailability of curcumin nanoparticles was about 2.67 times of raw curcumin powder.The oral bioavailability of curcumin nanoparticles was significantly improved compared with raw curcumin powder.Seen from the average residence time,the retention time of curcumin nanoparticles in vivo is longer than raw curcumin powder and can give full play to the effect.10.The analysis results of in vitro-in vivo correlation showed that:In according to the regression equationy= 0.8899 x-4.4615,R2 = 0.7010,R2 is smaller than the corresponding critical value R2 = 0.9170(P<0.01,n = 6),which showed that the there is no correlation between in vivo and in vitro.This may be because the curcumin as IV drugs in the BCS classification,the synthesis factors of the dissolution rate and the membrane permeability influence the absorption rate of curcumin in vivo.The dissolution rate of curcumin nanoparticles is accelerated,but the intestinal transmission speed does not change for nanoparticles.Therefore,this may lead to the limited relevance of curcumin nanoparticles in vivo and in vitro.11.The tissue distribution experimental results of curcumin nanoparticles in rats showed that the distribution in bioavailability time point respectively to detect the concentration of curcumin in the organizations of rats,it can be seen that curcumin nanoparticles distribution is much larger than raw curcumin powder in various organizations,this illustrated that the particles size of curcumin nanoparticles was small to make curcumin can with good absorption in each organization and to achieve efficacy.Distribution of the highest heart and liver,for example,has carried on the pharmacokinetics of curcumin nanoparticles.the concentration of curcumin nanoparticles is higher in the rat cardiac tissue,the reason is that the heart is the blood of the most intensive areas,the blood left in the first place in the heart after the drugs into the blood,and the particle size of nanoparticles is smaller and higher solubility than raw curcumin powder,so the nanodrugs will remain a long time in heart tissues.The high concentration and a longer retention time of drugs in the heart means that curcumin nanoparticles in the clinical treatment of antibacterial,antioxidant play an important role.In addition to the heart,the distribution of drugs in the liver is also high,this is because in addition to the liver is the blood of the most intensive areas,and is also a major metabolic organs;Particle size decreases can enhance the water solubility of curcumin,increase the blood drug concentration,and provide favorable conditions for the protective effect of curcumin on liver.And curcumin itself has the ability of protecting liver,and has a certain ability to repair liver fibrosis in the process of liver damage.From the above experiment results,the curcumin nanoparticles prepared in this research had small particle size,uniform particle size distribution,low solvent residual and low crystallinity.The enhancement of solubility of curcumin improved the bioavailability,antioxidant activity and the drug content in each organs,which made curcumin nanoparticles had great potential in the development of antioxidant drug in clinical. |
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