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Preliminary Studies on Lipid Vesicles Containing Uricase for Hyperuricemia

Author: WangNa
Tutor: ZhaoChunJing；ZhangJing
School: Chongqing Medical University
Course: Pharmacology
Keywords: Hyperuricemia Uricase Lipid nanoparticles Active Stability
CLC: R944
Type: Master's thesis
Year: 2010
Downloads: 27
Quote: 0
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Abstract

Uricase (Uricase, UOX) have an important role in the purine metabolic pathway, which molecular oxygen as a receptor catalyzed decomposition of the uric acid. Most mammals contain UOX, can be decomposed into higher solubility than uric acid, allantoin uric acid metabolites of purine nucleotide units of nucleic acids; human body lack UOX the purine catabolic only generates uric acid, followed by uric acid by renal excretion, which leads to the concentration of serum uric acid in the body than other mammals. When uric acid generation rate exceeds the capacity of renal excretion, plasma uric acid levels significantly increased, causing hyperuricemia. UOX can significantly reduce the levels of uric acid in the blood plasma, and to treat gout and kidney disease caused by hyperuricemia secondary. Lipid nanoparticles as a drug carrier, release, targeting, and reduce drug toxicity. This article was prepared of UOX lipid nanoparticles and study their physical and chemical properties, in order to extend the period UOX time in the role of the body, improve the activity of the enzyme, increase stability and reduce immunogenicity and antigenicity. Method: 1. Sephadex G-200 column separation of lipid nanoparticles and free drug with Coomassie brilliant blue G-250 staining method for the determination of the protein content, thus entrapment efficiency was determined. 2. Using the reverse evaporation prepared the UOX lipid nanoparticles. The use of single-factor design, screening the UOX lipid nanoparticles prescription. 3. Investigated through the determination of the activity of the enzyme the UOX lipid nanoparticles and UOX optimum temperature, optimum pH and Michaelis-Menten constant (Km). Using the fluorescent spectrophotometry the blank liposomes containing fluorescein isothiocyanate (FITC) the UOX liposomes, and UOX fluorescence scanning, visits UOX and film interactions. By measuring enzyme activity were investigated the UOX lipid nanoparticles and the UOX storage stability, thermal stability, pH stability, anti-tryptic ability and some organic compounds on the enzyme uricase. 5 UOX lipid nanoparticles and UOX as antigen rats immunized prepared Anti UOX serum, detected by ELISA, the antibody titer of serum anti UOX, the comparison rats immunogenicity. The 6. Hypoxanthine 500 mg / kg and oxonic potassium 100 mg / kg rat hyperuricemia animal model, the UOX lipid nanoparticles in vivo preliminary Pharmacodynamic study. Results: 1. Sephadex G-200 column separation of lipid nanoparticles and free drug. UOX gel column average recovery rate was 98.29%. That The method is simple, high sensitivity, good reproducibility, specificity, accurate determination of UOX the lipid nanoparticles UOX content and encapsulation efficiency. 2 the optimization process prepared UOX lipid nanoparticles Best prescription: ether water ratio of 3:1; SPC: CH = 1:1; dosage mg. Best prescription under the conditions, the average encapsulation efficiency was 64.24%, an average particle size of 206.73 nm, polydispersity coefficient of 0.247, the zeta potential of -37.33 mV. Lipid Nanoparticles with UOX in 3.UOX optimal temperatures were 40 ° C, activity was significantly higher than that of free UOX and UOX lipid nanoparticles. The optimum temperature, UOX lipid nanoparticles optimum pH value of 8.0, free UOX optimum pH of 8.5, and active the UOX lipid nanoparticles significantly higher than the free UOX. The UOX lipid nanoparticles Km below the free UOX, increase the affinity between UOX lipid nanoparticles substrate. By fluorescence spectrophotometry the blank liposomes containing fluorescein isothiocyanate (FITC), the UOX liposomes as well as the UOX fluorescence scanning, the results show that the electrostatic interaction and hydrophobic interaction between the UOX molecules with FITC, thus UOX fat quality nanoparticles in UOX lipid membrane interactions. 4. Stability Experimental results show that were significantly higher than in the storage stability, thermal stability, pH stability, anti-trypsin the hydrolysis ability and part organic compounds on the enzyme activity, UOX lipid nanoparticle stability UOX. Immunogenicity experimental results show that the antigen preparation to the UOX lipid nanoparticles and UOX rat antisera titer of 1: 500 and 1: 8000, Description UOX lipid nanoparticles can effectively reduce immunogenicity. 6 vivo preliminary pharmacodynamic experiments showed that injection UOX lipid nanoparticles, uric acid, from the high concentration (489.61μmol / L) down to the normal concentration of (240μmol / L) time is less than 3 h, However, in the injection UOX the normal concentration dropped from a high concentration to the multi-purpose 6 h. UOX lipid nanoparticles inhibit uric acid levels as high as 88.72%. After intravenous UOX nanoparticles, uric acid levels at 12 h to reach the lowest level (55.24μmol / L) Meanwhile, UOX drops 189.94μmol / L, model group only of drops 271.67μmol / L. Vivo pharmacodynamic studies have shown that in the rat model of of UOX lipid nanoparticles reduce uric acid levels more obvious. Conclusion: This article was successfully prepared UOX lipid nanoparticles, its high encapsulation efficiency, improve the activity of the enzyme, increase stability and reduce immunogenicity, and significantly lower blood levels of uric acid in the body can be.

Preliminary Studies on Lipid Vesicles Containing Uricase for Hyperuricemia

Abstract

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