Assessment of the Utility of Social Media for Broad-Ranging Statistical Signal Detection in Pharmacovigilance: Results from the WEB-RADR Project.

INTRODUCTION AND OBJECTIVE: Social media has been proposed as a possibly useful data source for pharmacovigilance signal detection. This study primarily aimed to evaluate the performance of established statistical signal detection algorithms in Twitter/Facebook for a broad range of drugs and adverse events. METHODS: Performance was assessed using a reference set by Harpaz et al., consisting of 62 US Food and Drug Administration labelling changes, and an internal WEB-RADR reference set consisting of 200 validated safety signals. In total, 75 drugs were studied. Twitter/Facebook posts were retrieved for the period March 2012 to March 2015, and drugs/events were extracted from the posts. We retrieved 4.3 million and 2.0 million posts for the WEB-RADR and Harpaz drugs, respectively. Individual case reports were extracted from VigiBase for the same period. Disproportionality algorithms based on the Information Component or the Proportional Reporting Ratio and crude post/report counting were applied in Twitter/Facebook and VigiBase. Receiver operating characteristic curves were generated, and the relative timing of alerting was analysed. RESULTS: Across all algorithms, the area under the receiver operating characteristic curve for Twitter/Facebook varied between 0.47 and 0.53 for the WEB-RADR reference set and between 0.48 and 0.53 for the Harpaz reference set. For VigiBase, the ranges were 0.64-0.69 and 0.55-0.67, respectively. In Twitter/Facebook, at best, 31 (16%) and four (6%) positive controls were detected prior to their index dates in the WEB-RADR and Harpaz references, respectively. In VigiBase, the corresponding numbers were 66 (33%) and 17 (27%). CONCLUSIONS: Our results clearly suggest that broad-ranging statistical signal detection in Twitter and Facebook, using currently available methods for adverse event recognition, performs poorly and cannot be recommended at the expense of other pharmacovigilance activities.

Bioadhesive nanoparticles of fungal chitosan for oral DNA delivery.

Chitosan is an ideal candidate for oral DNA delivery due to its mucoadhesive properties. Chitosan (CS) produced under GMP conditions from fungal source was used to encapsulate a plasmid DNA coding for a reporter gene. Nanoparticles made by complex coacervation of CS and DNA had a size around 200 nm, a positive zeta potential, a high association of DNA and protected the plasmid against nuclease degradation. Their transfection ability was assessed in differentiated intestinal Caco-2 cells. An N/P ratio of 4 and a DNA concentration of 8 microg/ml were the optimal conditions leading to a transfection efficiency similar to the one reached with polyethyleneimine (PEI)-DNA complexes without cytotoxicity. M cells in monolayers influenced DNA uptake up to 8 microg of DNA/ml when complexed with CS. Fungal trimethylchitosan was also tested but the complexes interactions were too strong to induce transfection in vitro. Confocal microscopy studies showed that CS/DNA and PEI/DNA nanoparticles were found at the apical surface of cell monolayers and DNA was co-localized within the nucleus. Quantification seemed to show that more DNA was associated with the cells when incubated with CS nanoparticles and that the presence of M cells slightly influenced DNA uptake when complexed with CS. In conclusion, we developed a new nanocarrier made of fungal CS promising for oral gene delivery and oral DNA vaccination.

Targeting of tumor endothelium by RGD-grafted PLGA-nanoparticles loaded with paclitaxel.

Paclitaxel (PTX)-loaded PEGylated PLGA-based nanoparticles (NP) have been previously described as more effective in vitro and in vivo than taxol. The aim of this study was to test the hypothesis that our PEGylated PLGA-based nanoparticles grafted with the RGD peptide or RGD-peptidomimetic (RGDp) would target the tumor endothelium and would further enhance the anti-tumor efficacy of PTX. The ligands were grafted on the PEG chain of PCL-b-PEG included in the nanoparticles. We observed in vitro that RGD-grafted nanoparticles were more associated to human umbilical vein endothelial cells (HUVEC) by binding to alpha(v)beta(3) integrin than non-targeted nanoparticles. Doxorubicin was also used to confirm the findings observed for PTX. In vivo, we demonstrated the targeting of RGD and RGDp-grafted nanoparticles to tumor vessels as well as the effective retardation of TLT tumor growth and prolonged survival times of mice treated by PTX-loaded RGD-nanoparticles when compared to non-targeted nanoparticles. Hence, the targeting of anti-cancer drug to tumor endothelium by RGD-labeled NP is a promising approach.

Paclitaxel-loaded PEGylated PLGA-based nanoparticles: in vitro and in vivo evaluation.

The purpose of this study was to develop Cremophor EL-free nanoparticles loaded with Paclitaxel (PTX), intended to be intravenously administered, able to improve the therapeutic index of the drug and devoid of the adverse effects of Cremophor EL. PTX-loaded PEGylated PLGA-based were prepared by simple emulsion and nanoprecipitation. The incorporation efficiency of PTX was higher with the nanoprecipitation technique. The release behavior of PTX exhibited a biphasic pattern characterized by an initial burst release followed by a slower and continuous release. The in vitro anti-tumoral activity was assessed using the Human Cervix Carcinoma cells (HeLa) by the MTT test and was compared to the commercial formulation Taxol and to Cremophor EL. When exposed to 25 microg/ml of PTX, the cell viability was lower for PTX-loaded nanoparticles than for Taxol (IC(50) 5.5 vs 15.5 microg/ml). Flow cytometry studies showed that the cellular uptake of PTX-loaded nanoparticles was concentration and time dependent. Exposure of HeLa cells to Taxol and PTX-loaded nanoparticles induced the same percentage of apoptotic cells. PTX-loaded nanoparticles showed greater tumor growth inhibition effect in vivo on TLT tumor, compared with Taxol. Therefore, PTX-loaded nanoparticles may be considered as an effective anticancer drug delivery system for cancer chemotherapy.

PEGylated quaternized copolymer/DNA complexes for gene delivery.

The aim of this study was to improve the colloidal stability, decrease unspecific interactions with cells and blood components of a novel gene delivery system composed of epsilon-caprolactone and quaternized epsilon-caprolactone. For this purpose, diblock 50/50 copolymer was used to generate complexes with DNA by either the solvent evaporation technique and by dialysis. The size, surface charge and degree of interaction of the plasmid-loaded formulations were measured. Then, polyplexes were combined with a poly(CL)-b-PEG copolymer to create a hydrophilic corona on the surface of the complexes. The cytotoxicity, transfection efficiency and cellular uptake of polyplexes and their association with PEG were evaluated on HeLa cells. The dialysis method did not allow to reduce the size of complexes as compared to the solvent evaporation method. The zeta potential of polyplexes became positive from a charge ratio of 4. The degree of interaction of copolymer with plasmid DNA was very high. Cytotoxicity and transfection efficiency were found to be comparable to polyethylenimine 50 kDa. Association of polyplexes with poly(CL)-b-PEG copolymer led to a small increase in particle size and a sharp decrease of charge surface. Cytotoxicity, transfection efficiency and cellular uptake were significantly reduced relative to unshielded copolymer/DNA complexes. The PEGylated formulations may be an attractive approach for an in vivo application.

Copolymers of epsilon-caprolactone and quaternized epsilon-caprolactone as gene carriers.

New copolymers of epsilon-caprolactone (CL) and gamma-bromo-epsilon-caprolactone quaternized by pyridine (Py+CL) were investigated as non-viral vectors for gene delivery. Copolymers with two molar compositions (50 Py+CL/50 CL and 80 Py+CL/20 CL), each with a diblock or a random structure, were used to prepare nanoparticulate complexes with DNA. Average size and surface charge of the complexes and extent of the complexation were measured. The DNA condensation by the copolymers was analysed by a gel retardation assay. Cytotoxicity and transfection efficiency of the copolymers were also evaluated in HeLa cells and compared with polyethylenimine 50 kDa. The size of the polyplexes was approximately 200 nm. The zeta potential first increased with the copolymer/DNA charge ratio and became positive for charge ratios in the 2-4 range depending on the type of copolymer. DNA was completely condensed within the nanoparticles and the degree of interaction was very high. Cytotoxicity and transfection efficiency were found to be comparable to polyethylenimine 50 kDa. The experimental results suggest that the novel copolymers can be used as novel gene delivery vectors.

On-line determination of fluconazole in blood and dermal rat microdialysates by microbore high-performance liquid chromatography.

To study the distribution of fluconazole in the dermis of the rat, on-line microdialysis using double-site sampling coupled with a microbore HPLC system was developed. The chromatographic conditions consisted of a mobile phase of 20 mM diammonium phosphate-acetonitrile (75:25, v/v, pH 7.0) pumped through a microbore C(18) column at 40 microl/min. The eluent was monitored with UV detector with UZ flow cell (30 mm path length) at 210 nm. A microbore 10-port pneumatic valve fitted with two loops of 1 microl was used to collect and directly inject microdialysates from jugular and dermal probes. The retention time was 5.8 min for fluconazole and 10.1 min for its fluorinated analog, UK-54373 used as a retrodialysis marker. The assay was precise, with inter- and intra-assay relative standard deviation values of 0.64 and 0.71%, respectively, and with a good linearity (r=0.999) in the range of 0.15-20 microg/ml with only 1 microl injected onto the column. The LOD and LOQ values for fluconazole were 0.100 and 0.150 microg/ml, respectively. The applicability of the method was demonstrated by studying the disposition of fluconazole in blood and dermis following i.v. bolus at a dose of 10 mg/kg.