Rhenium-188-Labeled DTPA: a new radiopharmaceutical for intravascular radiation therapy

Balloon angioplasty is a standard treatment for artherosclerotic coronary artery disease. However, its clinical value is reduced by a high restenosis rate. A new concept in preventing restenosis is the use of a liquid-filled balloon containing a beta-emitting radioisotope. In this study, we performed biodistribution studies of Re-188 perrhenate and Re-188 diethylenetriaminopentaacetate (DTPA) to assess the resulting organ dose values in the event of balloon rupture if these agents are used for the clinical inhibition of restenosis after percutaneous transluminal coronary angioplasty (PTCA). After injecting Re-188 preparations intravenously, rats were killed at 10 min, 30 min, 60 min, 2 h, and 6 h ( n =5 per group). Tissue concentrations were calculated and expressed as percent injected dose per gram or per milliliter (%ID/g or %ID/mL). In addition, urine excretion and thyroid gland uptake were evaluated in rats ( n=5 per group) with a gamma camera after administration of 37 MBq (1 mCi) of each agent. Our data showed that both agents were excreted primarily via urine. However, the excretion of Re-188 DTPA was much faster than that of Re-188 perrhenate via the urinary system. The biodistribution data revealed that radioactivity levels in the stomach and the thyroid gland were high in the perrhenate group but low in the Re-188 DTPA group. The concentration levels in other tissues including lung, liver, testis, muscle, and blood were low throughout this study for both agents. The thyroid radiation value in the Re-188 perrhenate group was 0.163 mGy/MBq, which was much higher than that of the Re-188 DTPA group (0.0167 mGy/MBq). The stomach radiation value was as high as 0.127 mGy/MBq for Re-188 perrhenate, compared with 0.013 mGy/MBq for Re-188 DTPA. In conclusion, in the event of balloon rupture, the release of Re-188 DTPA results in lower radiation doses than Re-188 perrhenate, especially to the thyroid gland and the stomach. Our data suggest that Re-188 DTPA is a useful radiopharmaceutical for endovascular irradiation.     

An immunohistochemical and immunoelectron microscopic study of adhesion molecules in synovial pannus formation in rheumatoid arthritis

To investigate the mechanism of synovial pannus formation in rheumatoid arthritis, immunohistochemical and immunoelectron microscopic studies with monoclonal antibodies against the adhesion molecules, CD54 (ICAM-1), CD 11a (LFA-1), CDw49a (VLA-1), CDw49b (VLA-2), CDw49c (VLA-3), Cdw49d (VLA-4) and CDw49e (VLA-5), were carried out to determine the pattern of distribution of these molecules at the rheumatoid synovial cartilage junction. Treatment with anti-ICAM-1 resulted in membrane staining of most of the macrophages and fibroblasts infiltrating the synovial tissue and bordering the pannus-cartilage junction, suggesting the possibility that ICAM-1 may function to facilitate the adhesion of synovial type A cells bearing ICAM-1 to type B cells of the pannus. ICAM-1-positive macrophages and fibroblasts were often found to be in contact with lymphoid cells, suggesting also that a cellular immune reaction occurs in the formation of the pannus. In addition, VLA-3, VLA-4 and, particularly, VLA-5 were the predominant1 integrins expressed by rheumatoid synovial pannus. Since these three integrins all function as fibronectin receptors, it is possible that the fibronectin-rich environment of the rheumatoid cartilage surface effectively traps pannus cells expressing high levels of these molecules. The VLA-5 molecule was found in a pericellular and interterritorial matrix distribution in the present study, strongly suggesting that a recepfor-ligand interaction between VLA-5 and cartilage matrix may occur at the early stage of pannus formation. Furthermore, an increase in1 integrin may be necessary for the growth of the pannus and also for the upregulation of the VLA molecules, leading secondarily to increased attachment.     

温度敏感原位凝胶中药物的扩散行为温度敏感原位凝胶中药物的扩散行为

环境敏感凝胶对外界物理或化学条件的微小变化发生响应的性质在药物控制释放领域得到广泛应用.原位凝胶(in situ gel)是指高分子材料的溶液因温度[1,2]、离子强度[3]或pH[4]的改变而在用药部位发生相转变,形成的半固体制剂.由于完美地融合了液体与凝胶制剂的优点,该药物传递系统近年来已逐步发展成为环境敏感凝胶最受瞩目的分支.     

环孢素-泊洛沙姆188固体分散体的体外评价

目的以泊洛沙姆188（F68）为载体制备环孢素（CsA）固体分散体并考察其体外溶出。方法以溶剂一熔融法制备固体分散体，以差示扫描量热法（DSC）和X．射线衍射法鉴定CsA在体系中的存在状态，以FTIR表征药物与载体的相互作用，以摇瓶法测定CsA的溶解度，按《中国药典》溶出度第三法测定CsA从物理混合物和固体分散体中的溶出。结果X-射线衍射图谱显示CsA结晶衍射峰消失，提示药物以无定形或分子状态存在于固体分散体中。FTIR结果表明药物与载体间无相互作用。药物溶解度和溶出度均随着F68比例的增加而增大，固体分散体和物理混合物60min的累积溶出百分率分别为99．32％和75．41％，两者具显著性差异（P〈0．01）。结论F68能提高CsA的溶解度和溶出度，可用来制备CsA的固体剂型。     

Development and characterisation of levosulpiride-loaded suppositories with improved bioavailability in vivo

The purpose of this study was to develop and characterize levosulpiride loaded liquid suppository with improved bioavailability. The content of levosulpiride-loaded liquid suppositories were optimized in a series of experiments using various weight ratios of P188, P407, Tween 80, and drug. The suppositories were liquid at room temperature, however, when rectally administered, they became gel at body temperature. Their rheological properties and release characteristics were determined in vitro while pharmacokinetic study was performed after its rectal administration in rats and compared with drug suspension. Poloxamer 188 and Twee 80 decreased the gelation temperature and gelation time, but increased the gel strength and mucoadhesive force of liquid suppositories. Liquid suppository composed of [Levosulpiride/P 188/P 407/Tween 80 (1/15/17/3%)] with a gelation temperature of about 30.7?°C remained liquid at 25?°C, but converted to gel at 30–36.5?°C, resulting in easy administration and rapid gelation inside the body. This liquid suppository gave a considerably increased dissolution rate reflected in a meaningfully higher plasma concentration and 7.1-fold AUC values of levosulpiride in rats as compared to the drug suspension. Hence, liquid suppository system could be used for enhanced bioavailability of levosulpiride-loaded pharmaceutical products.     

Preparation and first biological evaluation of novel Re-188/Tc-99m peptide conjugates with substance-P

IntroductionNew ¹⁸⁸Re and ^99mTc peptide conjugates with substance- P (SP) were prepared and biologically evaluated. The radiopharmaceuticals have been labelled with the [M≡N]²⁺ (M=^99mTc, ¹⁸⁸Re) core using a combination of π-donor tridentate and π-acceptor monodentate ancillary ligands.MethodsThe new radiopharmaceuticals have been prepared through a two-step reaction by simultaneous addition of the tridentate and monodentate ligands to a vial containing a preformed [M≡N]²⁺ core. The tridentate ligand was formed by linking two cysteine residues to the terminal arginine of the undecapeptide SP, whereas the monodentate ligand was a tertiary phosphine. The preparation of the corresponding Re-188 derivative required developing a more complex chemical procedure to obtain the [Re≡N]²⁺ core in satisfactory yields. Characterization of the resulting products was obtained by chromatographic methods. Biological evaluation was performed for both Tc-99m and Re-188 derivatives by in-vitro studies on isolated cells expressing NK1-receptors. In-vivo imaging in mice was carried out using a small-animal YAP(S)PET tomograph.ConclusionNew Tc-99m and Re-188 peptide radiopharmaceuticals with SP have been prepared in high-yield and with high-specific activity. Both Tc-99m and Re-188 peptide radioconjugates exhibit high affinity for NK1 receptors, thus giving further evidence to the empirical rule that structurally related Tc-99m and Re-188 radiopharmaceuticals exhibit identical biological properties.     

Expression and function of microRNA-188-5p in activated rheumatoid arthritis synovial fibroblasts

Activated synovial fibroblasts in rheumatoid arthritis (RASF) play a critical role in the pathology of rheumatoid arthritis (RA). Recent studies suggested that deregulation of microRNAs (miRs) affects the development and progression of RA. Therefore, we aimed to identify de-regulated miRs in RASF and to identify target genes that may contribute to the aggressive phenotype of RASF. Quantitative real-time PCR revealed a marked downregulation of miR-188-5p in synovial tissue samples of RA patients as well as in RASF. Exposure to the cytokine interleukine-1β lead to a further downregulation of miR-188-5p expression levels compared to control cells. Re-expression of miR-188-5p in RASF by transient transfection significantly inhibited cell migration. However, miR-188-5p re-expression had no effects on glycosaminoglycan degradation or expression of repellent factors, which have been previously shown to affect the invasive behavior of RASF. In search for target genes of miR-188-5p in RASF we performed gene expression profiling in RASF and found a strong regulatory effect of miR-188-5p on the hyaluronan binding protein KIAA1199 as well as collagens COL1A1 and COL12A1, which was confirmed by qRT-PCR. In silico analysis revealed that KIAA1199 carries a 3’UTR binding site for miR-188-5p. COL1A1 and COL12A1 showed no binding site in the mRNA region, suggesting an indirect regulation of these two genes by miR-188-5p. In summary, our study showed that miR-188-5p is down-regulated in RA in vitro and in vivo, most likely triggered by an inflammatory environment. MiR-188-5p expression is correlated to the activation state of RASF and inhibits migration of these cells. Furthermore, miR-188-5p is directly and indirectly regulating the expression of genes, which may play a role in extracellular matrix formation and destruction in RA. Herewith, this study identified potential novel therapeutic targets to inhibit the development and progression of RA.     

Expression and function of microRNA-188-5p in activated rheumatoid arthritis synovial fibroblasts

Activated synovial fibroblasts in rheumatoid arthritis (RASF) play a critical role in the pathology of rheumatoid arthritis (RA). Recent studies suggested that deregulation of microRNAs (miRs) affects the development and progression of RA. Therefore, we aimed to identify de-regulated miRs in RASF and to identify target genes that may contribute to the aggressive phenotype of RASF. Quantitative real-time PCR revealed a marked downregulation of miR-188-5p in synovial tissue samples of RA patients as well as in RASF. Exposure to the cytokine interleukine-1β lead to a further downregulation of miR-188-5p expression levels compared to control cells. Re-expression of miR-188-5p in RASF by transient transfection significantly inhibited cell migration. However, miR-188-5p re-expression had no effects on glycosaminoglycan degradation or expression of repellent factors, which have been previously shown to affect the invasive behavior of RASF. In search for target genes of miR-188-5p in RASF we performed gene expression profiling in RASF and found a strong regulatory effect of miR-188-5p on the hyaluronan binding protein KIAA1199 as well as collagens COL1A1 and COL12A1, which was confirmed by qRT-PCR. In silico analysis revealed that KIAA1199 carries a 3’UTR binding site for miR-188-5p. COL1A1and COL12A1 showed no binding site in the mRNA region, suggesting an indirect regulation of these two genes by miR-188-5p. In summary, our study showed that miR-188-5p is down-regulated in RA in vitro and in vivo, most likely triggered by an inflammatory environment. MiR-188-5p expression is correlated to the activation state of RASF and inhibits migration of these cells. Furthermore, miR-188-5p is directly and indirectly regulating the expression of genes, which may play a role in extracellular matrix formation and destruction in RA. Herewith, this study identified potential novel therapeutic targets to inhibit the development and progression of RA.     

Bottom-Up and Top-Down Approaches to Explore Sodium Dodecyl Sulfate and Soluplus on the Crystallization Inhibition and Dissolution of Felodipine Extrudates

The objectives of this study were to explore sodium dodecyl sulfate (SDS) and Soluplus on the crystallization inhibition and dissolution of felodipine (FLDP) extrudates by bottom-up and top-down approaches. FLDP extrudates with Soluplus and SDS were prepared by hot melt extrusion, and characterized by polarized light microscopy, differential scanning calorimetry, and fourier transform infrared spectroscopy. Results indicated that Soluplus inhibited FLDP crystallization, and the whole amorphous solid dispersions (ASDs) were binary FLDP-Soluplus (1:3) and ternary FLDP-Soluplus-SDS (1:2:0.15～0.3 and 1:3:0.2～0.4) extrudates. Internal SDS (5%-10%) decreased glass transition temperatures of FLDP-Soluplus-SDS ternary ASDs without presenting molecular interactions with FLDP or Soluplus. The enhanced dissolution rate of binary or ternary Soluplus-rich ASDs in the nonsink condition of 0.05% SDS was achieved. Bottom-up approach indicated that Soluplus was a much stronger crystal inhibitor to the supersaturated FLDP in solutions than SDS. Top-down approach demonstrated that SDS enhanced the dissolution of Soluplus-rich ASDs via wettability and complexation with Soluplus to accelerate the medium uptake and erosion kinetics of extrudates, but induced FLDP recrystallization and resulted in incomplete dissolution of FLDP-rich extrudates. In conclusion, top-down approach is a promising strategy to explore the mechanisms of ASDs' dissolution, and small amount of SDS enhances the dissolution rate of polymer-rich ASDs in the nonsink condition.     

Preparation and evaluation of 188Re sulfide colloidal nanoparticles loaded biodegradable poly (L‐lactic acid) microspheres for radioembolization therapy

Radioembolization with radioactive microspheres has been an effective method for the treatment of liver lesions. The aim of this study was to prepare carrier‐free ¹⁸⁸Re loaded poly (L‐lactic acid) (PLLA) microspheres through ¹⁸⁸Re sulfide colloidal nanoparticles (¹⁸⁸Re‐SC nanoparticles). The formation of ¹⁸⁸Re‐SC nanoparticles was confirmed by ultraviolet‐visible spectrophotometry. The labeling yield of ¹⁸⁸Re‐SC nanoparticles was verified using the RTLC method. Effects of synthesis parameters on morphology and size of prepared ¹⁸⁸Re‐sulfide colloidal‐PLLA microspheres (¹⁸⁸Re‐SC‐PLLA microspheres) were studied by scanning electron microscopy. In vitro stability of ¹⁸⁸Re‐SC‐PLLA microspheres was investigated in normal saline at room temperature and in human serum at 37°C. In vivo distribution studies and gamma camera imaging were performed in healthy BALB / c mice. The microspheres could be prepared with sizes between 13 and 48 μm (modal value 29 μm) and radiolabeling efficiency >99%. After incubation, the microspheres were found stable in vitro up to 72 hours. The biodistribution after intravenous injection in healthy BALB / c mice showed high accumulation in lung as a first capture pathway organ for microsphere followed by great retention over 48 hours for these microspheres. These data show that ¹⁸⁸Re‐SC‐PLLA microspheres are suitable candidate for clinical studies.