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The aim of this study was to assess the potential of a novel alkaline enzymosome to deliver uricase from Bacillus fastidious (UBF) and enhance its biochemical and pharmacological characteristics. The in vitro catalytic activity of the UBF loaded in the novel alkaline enzymosomes (ESUBFs) was almost 3.8 times that of free UBF at the optimum pH or 1.5 times that of free UBF at the physiological pH. Following intravenous (i.v.) administration (2000 mU/kg) in rats, ESUBFs provided significantly higher (22.5-fold) area under the plasma concentration (AUC) and longer (8.2-fold) circulation half-life (t(1/2)) compared with free UBF, respectively. Further, it took only 4.5h (or 1.1h) for ESUBFs to lower the plasma uric acid concentration from a high level to the normal level of rat (or human beings), compared with 7.6h (or 5.4h) for free UBF. Our results showed that ESUBFs could efficiently deliver UBF and favorably modify its biochemical and pharmacological characteristics by increasing the AUC, t(1/2), and catalytic activity. Therefore, ESUBFs might be a preferred alternative to cure hyperuricemia and gout.

The study described the development of lipid vesicles as colloidal carriers for uricase, an enzyme with low activity at physicological conditions and low stability in vitro and in vivo. The lipid vesicles containing uricase (UOXLVs) were prepared and the process parameters were optimized with the indexes of entrapment efficiency, polydispersion, particle size, and zeta potential. The storage stability of uricase in lipid vesicles was significantly increased compared to that of free uricase at 4°C. The stability to proteolytic digestion was also increased obviously by entrapping the uricase in the lipid vesicles. In vitro and in vivo pharmacodynamic studies on the hyperuricemia rat model explicitly suggested that the uricase entrapped by UOXLVs possessed high uricolytic activity and distinctively decreased the uric acid level.

Uricase-containing lipid vesicles (UOXLVs) were prepared by reverse-phase evaporation method with high efficiency and the characteristics of UOXLVs were described. The average size and zeta potential of UOXLVs obtained by the optimized formulation were 205.47 nm and -37.33 mV, respectively. Uricase was encapsulated in the alkaline aqueous phase of the lipid vesicle and the stability of its tetrameric structure was thus improved and its activity preserved. The storage stability of uricase in lipid vesicles was significantly increased compared to that of free uricase at 4 degrees C in borate buffer of pH 8.5. At 55 degrees C, free uricase was deactivated much more quickly especially at lower concentration predominantly due to enhanced dissociation of uricase into subunits. An intrinsic tryptophan of uricase recovered from the lipid vesicle thermally treated at 55 degrees C revealed that a partially denatured uricase molecule was stabilized through its hydrophobic interaction with lipid vesicle membrane. This interaction was depressed mainly by dissociation of uricase into subunits. At the physiological pH, significant increase of enzyme activity was found for the uricase entrapped in the lipid vesicles (1.8 times that of free uricase) at their respective optimum pH. The shift of optimum pH and increased uricolytic activity suggested the conformation change of the uricase during the entrapment process. The stability to proteolytic digestion was increased obviously by entrapping the uricase in the lipid vesicles. UOXLVs also showed relatively slower loss in activity compared with free uricase when treated with some chemical reagents. Lastly, in vitro study explicitly indicated that the uricase entrapped by UOXLVs possessed higher uricolytic activity than that of native uricase solution.

The supermolecular curcumin (SMCCM) exhibiting remarkably improved solubility and release characteristics was fabricated to increase the oral bioavailability in rat as well as the antiproliferative and proapoptotic activities of curcumin (CCM) against human lung adenocarcinoma cell A549. SMCCM was characterized by differential scanning calorimetry, Fourier transform infrared spectroscopy, morphology and structure, aqueous solubility, and release behavior in vitro. Computer modeling of the supermolecular structure was performed. The pharmacokinetics, antiproliferative and proapoptotic activities of SMCCM were evaluated. The mechanisms by which SMCCM inhibited proliferation and induced apoptosis were identified. The formation of SMCCM was testified and the supermolecular structure was studied by a computer modeling technique. Compared to free CCM, SMCCM with much higher aqueous solubility exhibited obviously enhanced release and more favorable pharmacokinetic profiles, and, furthermore, SMCCM showed higher anticancer efficacy, enhanced induction of G2/M-phase arrest and apoptosis in A549 cells, which might be involved with the increases in reactive oxygen species production and intracellular Ca(2+) accumulation, and a decrease in mitochondrial membrane potential. SMCCM remarkably enhanced not only the oral bioavailability but also the antiproliferative and proapoptotic activities of CCM along with improved solubility and release characteristics of CCM.

Qun-You Tan,1,* Jing-Qing Zhang,2,* Na Wang,3,* Hong Yang,4 Xiaoling Li,5 Hua-Rong Xiong,2 Jian-Yong Wu,2 Chun-Jing Zhao,3 Hong Wang,2 Hua-Feng Yin2 1Department of Thoracic Surgery, Institute of Surgery Research, Daping Hospital, Third Military Medical University, Chongqing, 2Medicine Engineering Research Center, Chongqing Key Laboratory of Biochemical & Molecular Pharmacology, Chongqing Medical University, Chongqing, 3School of Pharmacy, Second Affiliated Hospital, Chongqing Medical University, Chongqing, 4School of Pharmacy, Medical College of Soochow University, Soochow, People's Republic of China; 5TJ Long School of Pharmacy and Health Sciences, University of the Pacific, Stockton, CA, USA*These authors contributed equally to this workObjective: Previous studies on various enzymosomes (functional lipid vesicles encapsulating an enzyme) have been mostly carried out in vitro and have focused on preserving catalytic activity and improving the stability of the enzyme. Until now, few studies have focused on their in vivo fate. Similarly, although we have previously reported the increased in vitro uricolytic activity (about 2.2 times higher than that of free uricase, or three times higher than that of PEGylated uricase, Puricase®, under physiological pH and temperature) and improved stability of the novel alkaline enzymosomes (functional lipid vesicles encapsulating uricase from Candida utilis: uricase-containing lipid vesicles, UOXLVs), it is still necessary to study the biological properties and hypouricemic effects of UOXLVs in vivo.Methods: The enzyme kinetics, pharmacokinetics, pharmacodynamics, immunogenicity, and preliminary safety of UOXLVs were evaluated.Results: The Michaelis constant (Km) value of the UOXLVs was slightly lower than that of the free enzyme. The enzyme release from the UOXLVs lasted over 12 hours and their circulation half-life was about sevenfold longer than that of the free uricase. Meanwhile, the UOXLVs had a 22-fold increase in the area under the curve compared with the free uricase. Furthermore, it took less than 3 hours for the UOXLVs to lower the plasma uric acid concentration from a high to a normal level, compared with 6 hours for the free uricase. In addition, the UOXLVs had much less immunogenicity than free uricase and were well tolerated by all animals throughout the observation period.Conclusion: The UOXLVs markedly improved the biological properties and enhanced the hypouricemic effects of uricase in vivo.Keywords: biological properties, hypouricemic effect, uricase, alkaline enzymosomes, in vivo