Preparation Of Curcumin Nanoparticles By Subcritical Water Method And Quality Evaluation

Curcumin,an important natural diketone pigment,is mainly isolated from the rhizomes of plants in the ginger family and the asparagus family,and has a wide range of applications in the food,chemical and pharmaceutical industries.Previous studies clearly demonstrated that curcumin has various pharmacological properties such as anti-inflammatory,antioxidant,anti-bacterial,anti-tumor,cardiovascular protection,etc.However,its practical application in the field of medicine is often hampered by their low solubility in aqueous media,which leads to a low bioavailability.Fortunately,nanotechnology has opened a new window to enhance the aqueous solubility of these APIs.Thus,in order to overcome this inherent disadvantage of curcumin and expand its use,this project was designed to prepare curcumin nanoparticles by the subcritical water techniques coupled with antisolvent precipitation method.The details of the study and the results are as follows.1.Preparation of curcumin nanoparticles by subcritical water with antisolvent precipitation method.The process of preparing curcumin nanoparticles by subcritical water coupled with the antisolvent method was investigated and determined as follows:the temperature of the antisolvent was 0°C,the temperature of the subcritical water was 120°C,the volume ratio of the solution to the antisolvent was 1:3,the stabilizer was 0.04%lactose,and the entrainment agent was 30%ethanol.The particle size of nanoparticles prepared under these conditions was 166 nm,and the conversion of curcumin nanoparticles was 65.2%.The properties of the nanoparticles were characterized by SEM,and the results showed that their morphology was spherical,while the morphology of curcumin powder was bulky and particle was determined to be 2μm-10μm.The FT-IR and HPLC patterns showed that the chemical structure of nanoparticles cannot be changed compared to that of curcumin powder.The results showed that the curumin nanoparticles had lower cry stallinity.The results showed that the cumulative permeation of curcumin nanoparticles was 192.57μg/cm~2in 24 h,which was much higher than that of curcumin powder（43.66μg/cm~2）.In the in vitro simulated digestion and absorption experiment,the digestion and absorption rate of nanoparticles was 11.2%,and that of curcumin powder was 7.6%.2.Evaluation of biological activity of curcumin nanoparticles.Antioxidant and antibacterial properties of curcumin nanoparticles were studied by in vitro experiments and the results were as follows.Compared with the curcumin powder,the nanoparticles showed a better scavenging ability of DPPH radicals.Its IC₅₀was 16.18μg/m L,while the IC₅₀of the curcumin powder was 23.64μg/m L.In the determination of reducing ability,when the drug concentration was 150μg/m L,the reducing ability of the nanoparticles was 12 times that of the curcumin powder.E.coli（E.coli）and Staphylococcus aureus（S.aureu）were effectively inhibited by nanoparticles,and they were not inhibited by APIs.The MIC for inhibition by nanoparticles was 100μg/m L for S.aureu and 200μg/m L for E.coli.The anti-inflammatory effect of curcumin nanoparticles was evaluated by the permeability of the mouse peritoneal cavity.The experimental results showed that the anti-inflammatory activity of curcumin nanoparticles was superior to that of the curcumin powder.3.In vivo metabolic kinetics study of curcumin nanoparticles.The metabolic behaviors of curcumin nanoparticles and curcumin curcumin powder in rabbits were investigated separately using rabbits as experimental animals.The blood concentration data were processed and analyzed by DAS 2.0 software.The results showed that the pharmacokinetic processes of curcumin nanoparticles in rabbits were in accordance with the one-compartment model.The peak blood concentration of curcumin nanoparticles was 83.85 ng/m L,which was 3.84 times higher than that of the curcumin powder（21.86 ng/m L）,and the bioavailability of nanoparticles in rabbits was 3.86 times higher than that of the curcumin powder.4.Nanoparticle lyophilized formulation.freeze-drying process was investigated by single factor and optimized by orthogonal optimization method,and the optimal process conditions were determined as follows:8%mannitol as freeze-drying protectant and pre-freezing at-80℃for 20 h.The freeze-dried preparation prepared under these conditions had a flat and smooth appearance without obvious collapse,good solubility.The particle size after solubilization was 223.5 nm with a zeta potential of-21.1 mv.The stability was investigated by accelerated experiments and long-term tests,and the results showed that the freeze-dried formulation of curcumin nanoparticles should be stored with care in a light-proof,low-temperature and dry place.In summary,curcumin was prepared into nanoparticles by the subcritical water coupling anti-solvent method,without the drug carrier,and the harm of carrier degradation to the human body was effectively avoided.Moreover,The properties of nanoparticles were stable,and their bioavailability,antioxidant,bacteriostatic and anti-inflammatory effects were enhanced.This study can provide theoretical guidance for the development of new curcumin nano dosage forms.