Preparation and In Vitro Evaluation of Povidone-Sodium Cholate- Phospholipid Mixed Micelles for the Solubilization of Poorly Soluble Drugs

Yuan Zhu,Shanshan Tong,Li Wang,Min Peng,Xia Cao,Ximing Xu,Jiangnan Yu 대한약학회 2010 Archives of Pharmacal Research Vol.33 No.6

Mixed micelles made of polyvinylpyrrolidone (PVP), sodium cholate, and phospholipids were prepared to improve the solubility of poorly water-soluble drugs. Sylibin, a drug used in treating liver diseases, was incorporated into the mixed micelles. The formulation of sylibin containing PVP-sodium cholate-phospholipid mixed micelles with an optimized composition (PVP/sodium cholate/phospholipid/silybin = 3:3:4:1~2 by weight) was obtained based on the study of pseudoternary phase diagrams. The critical micelle concentration was used to evaluate the micellar stability towards dilution. The results showed that addition of PVP to sodium-cholate-phospholipid mixed micelles increased stability. The solubility of sylibin in PVP-sodium cholate-phospholipid mixed micelles was higher than that in pure water or in sodium cholate-phospholipid mixed micelles. In a stability study, we found that PVP-sodium cholate-phospholipid mixed micelles showed good stability. After 3 months storage at 40oC, just 2.6% sylibin was lost with only minor changes of the particle size when compared to a reference formulation containing sodium cholate and phospholipid mixed micelles. In addition, the developed formulation significantly improved in vitro drug release. The time required to release 50% sylibin (t50%) from sodium cholate and phospholipid mixed micelles was 326 h, while the t50% from PVP-sodium cholate-phospholipid mixed micelles was only 51.1 h. Our results suggest that these mixed micelles might have significant potential application to the biomedical field.

Improved oral bioavailability of capsaicin via liposomal nanoformulation: preparation, in vitro drug release and pharmacokinetics in rats

Yuan Zhu,Miaomiao Wang,Jiajia Zhang,Wei Peng,Caleb Kesse Firempong,Wenwen Deng,Qilong Wang,Shicheng Wang,Feng Shi,Jiangnan Yu,Ximing Xu,Weiming Zhang 대한약학회 2015 Archives of Pharmacal Research Vol.38 No.4

This study innovatively prepared an effectivecapsaicin-loaded liposome, a nanoformulation with fewerirritants, for oral administration. The in vitro and in vivoproperties of the liposomal encapsulation were investigatedand the potential possibility of oral administration evaluated. The liposomal agent composed of phospholipid, cholesterol,sodium cholate and isopropyl myristate was prepared usingfilm-dispersion method. A level A in vitro–in vivo correlation(IVIVC) was established for the first time, which demonstratedan excellent IVIVC of both formulated and freecapsaicin in oral administration. Physicochemical characterizationsincluding mean particle size, zeta (f) potentialand average encapsulation efficiency of capsaicin-loadedliposome were found to be 52.2 ± 1.3 nm, -41.5 ±2.71 mv and 81.9 ± 2.43 %, respectively. In vivo, liposomalencapsulation allowed a 3.34-fold increase in relativebioavailability compared to free capsaicin. The gastricmucosa irritation studies indicated that the liposomal systemwas a safe carrier for oral administration. These resultssupport the fact that capsaicin, an effective drug for thetreatment of neuropathic pain, could be encapsulated inliposome for improved oral bioavailability. The excellentIVIVC of capsaicin-loaded liposome could also be a promisingtool in liposomal formulation development with anadded advantage of reduced animal testing.

Organizational Clientelism: An Analysis of Private Entrepreneurs in Chinese Local Legislatures

Xin Sun,Jiangnan Zhu,Yiping Wu 동아시아연구원 2014 Journal of East Asian Studies Vol.14 No.1

Extant literature on authoritarian legislatures argues that dictators set up quasi-democratic institutions to co-opt opposition and attract investors. We argue that dictators also nurture clientelistic ties with social groups useful to their rule, a previously overlooked function of authoritarian legislatures. Drawing on the case of Chinese local legislatures—namely, the local People's Congress and the local People's Political Consultative Conference—we find that Chinese local governments use these institutions to channel patronage to and gain political support from the private sector. Field interviews and an analysis of a nationwide firm-level survey show that private firms owned by local legislative members, while obtaining more bank loans, provide more support to the local government in various forms than those owned by nonmembers. This finding suggests that authoritarian legislatures, even those with weak policymaking efficacy, can help authoritarian states build stable alliances with social groups, thereby contributing to regime resilience.

Numerical study of conjugate heat transfer of steam and air in high aspect ratio rectangular ribbed cooling channel

Tieyu Gao,Jiangnan Zhu,Changwei Liu,Jiamin Xu 대한기계학회 2016 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.30 No.3

The relationship between flow field and heat transfer in an air/steam cooled ribbed channel was numerically investigated and compared. The width to height ratio was 4 and the rib height to hydraulic diameter was 0.078. The conjugate heat transfer method was adopted and a uniform heat source was located in the solid domain to simulate the actual heating method in the experiment. The GGI method was used to deal with the solid-fluid interface. The fluid field structure was shown by vortex core technology. We found that the wall heat flux distribution is similar with that of the Nusselt number, which is periodic. The temperature difference of a certain position on the inner and outer wall was less than 2 K. The Nusselt number reached its peak value at No.15-18 part and then decreased. The large width to height ratio led to strong interaction between the main flow fluid and the fluid in near wall region. As a result, an extra main flow secondary flow and two separation vortexes could be observed. These three additional vortexes were all in main flow region. The two separation vortexes approached to each other in flow direction and mixed into one vortex at low Reynolds number. When Reynolds number is larger than 30000, the two vortexes remain independent. The relative distance between them reaches the minimum value and the Nusselt number reaches the peak value at the same time. In addition, the flow field structure is mainly determined by Reynolds number and the fluid type cannot obviously influence the secondary flow distribution. The generation and separation of secondary flow as well as the mixing of secondary flows can enhance the local heat transfer strength.

Expression pattern of genes involved in maternal immune regulation during the peri-implantation and midgestation in Meishan pigs

Xiaoping Li,Zongping Zhang,Jiangnan Huang,Lijie Su,Mengjin Zhu,Mei Yu 한국유전학회 2013 Genes & Genomics Vol.35 No.3

In pigs, complex molecular cross-talk between the mother and embryo(s) especially maternal immunotolerance at the maternal-fetal interface has been postulated to play important roles on embryo/fetal loss during the peri-implantation and midgestation. In this study, we collected the endometrium samples in implantation sites at gestational day 15 (gd15), 26 (gd26)) and 50 (gd50)from Meishan pigs to evaluate the contribution of the genes participating in immune response by using porcine Affymetrix GeneChip.The results showed that totally 68immune related genes showed significantly differential expression at three stages, and the expression of these genes underwent drastic changes during the peri-implantation period (between gd15 and gd26). The identified genes including IL6 proinflammatory cytokine family,inflammatory chemokines (CCL28), IGF/IGFBP system,growth factors (FGF7) and adhesion molecules (ITGB3,PCDH15) may prove valuable for further investigations of porcine prenatal mortality.

Effects of rib angle and rib orientation on flow and heat transfer in two-pass ribbed channels

Tieyu Gao,Junxiong Zeng,Jiangnan Zhu,Jun Li,Jianying Gong 대한기계학회 2018 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.32 No.1

The secondary flows generated by the rib and the U-shaped bend play a vital role in heat transfer enhancement in two-pass ribbed channels. This paper focuses on the combined effects of rib orientations (N-type and P-type) and rib angles (from 30º to 75º) on flow and heat transfer in two-pass ribbed channels. The 3D steady Reynolds-averaged Navier–Stokes equations coupled with SST k-ω model are solved by using commercial software ANSYS CFX. The CFD model has been validated by experimental data with a good agreement. In addition, the comprehensive evolution of secondary flows and its effect on heat transfer are analyzed in detail by using vortex core technology. The results indicate that the key factor for local heat transfer enhancement is to transport more secondary flows into downstream passage without weakening local secondary flow and energy dissipation of upstream secondary flow. Furthermore, the rib orientation in passage 2 should consider the influence of rib angle so that the local main flow secondary flow has the same rotational direction with the most powerful upstream secondary flow to reduce the energy loss and speed up the growth of local main flow secondary flow as much as possible.

Structural Characterization of Microwave-Assisted Solution-Synthesized Strontium-Substituted Hydroxyapatite

Jianguo Liao,Yanqun Li,Xiali Guan,Jingxian Liu,Yongxiang Zhang,Yufen Xie,Zhengpeng Yang,Xingze Duan,Aiguo Zhou,Jiangnan Zhu 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2016 NANO Vol.11 No.10

Hydroxyapatite and strontium-substituted hydroxyapatite nanoparticles (n-HA and Sr-HA) were prepared by microwave-assisted solution synthesis with aqueous solutions of various Sr/(Sr+Ca) molar ratios ranging from 0% to 15%. The structural properties of the hydroxyapatite powders were investigated by X-ray powder diffraction, Fourier transform infrared spectroscopy and Raman spectra, field emission scanning electron microscopy coupled with energy dispersive X-ray spectrometry and transmission electron microscopy. The results confirmed that strontium ions had been incorporated into the hydroxyapatite lattice. The synthetic n-HA and Sr-HA nanocrystalline consisted of hydroxyapatite crystalline phase with hexagonal structure, and the particle size was 30–40 x 60–70 nm and 40–50 x 70–80 nm, respectively. The calcined HA particle size ranged from about 120 nm to 150 nm, the calcined Sr-HA products were composed of spherical aggregates with a size of about 70–100 nm. The incorporation of Sr ions lead to the formation of vacancies in the crystal structure of the HA. The results indicated that the strontium substitution did not change the crystal structures. More Sr resulted in less calcined crystallites and formed agglomerates owing to the size effect.