In vitro evaluation of the genotoxicity of poly(anhydride) nanoparticles designed for oral drug delivery

In the last years, the development of nanomaterials has significantly increased due to the immense variety of potential applications in technological sectors, such as medicine, pharmacy and food safety. Focusing on the nanodevices for oral drug delivery, poly(anhydride) nanoparticles have received extensive attention due to their unique properties, such as their capability to develop intense adhesive interactions within the gut mucosa, their modifiable surface and their biodegradable and easy-to-produce profile. However, current knowledge of the possible adverse health effects as well as, toxicological information, is still exceedingly limited. Thus, we investigated the capacity of two poly(anhydride) nanoparticles, Gantrez^® AN 119-NP (GN-NP) and Gantrez^® AN 119 covered with mannosamine (GN-MA-NP), and their main bulk material (Gantrez^® AN 119-Polymer), to induce DNA damage and thymidine kinase (TK^+/-) mutations in L5178Y TK^+/- mouse lymphoma cells after 24h of exposure. The results showed that GN-NP, GN-MA-NP and their polymer did not induce DNA strand breaks or oxidative damage at concentrations ranging from 7.4 to 600μg/mL. Besides, the mutagenic potential of these nanoparticles and their polymer revealed no significant or biologically relevant gene mutation induction at concentrations up to 600μg/mL under our experimental settings. Considering the non-genotoxic effects of GN-NP and GN-MA-NP, as well as their exceptional properties, these nanoparticles are promising nanocarriers for oral medical administrations.

Anticancer effect of a new benzophenanthridine isolated from Zanthoxylum madagascariense (Rutaceline)

Fractionation of the cyclohexane extract from the stem bark powder of Zanthoxylum madagascariense led to the isolation of a new benzophenanthridine-type alkaloid, hydrochloride of 2,3-methylendioxy-8-hydroxy- 7-methoxy-benzo[C]phenanthridine (Rutaceline), characterized on the basis of its spectral data. Rutaceline was evaluated for its antiproliferative capacity on the human colorectal adenocarcinoma (Caco-2) and the African green monkey kidney (Vero) cell lines. The 50% inhibition of cell growth (IC50) obtained after 24 h incubation was similar for both cells lines (110-115 microg/ml, i.e. 269-281 microM), but at 48 h the IC50 value for the Caco-2 cells was lower than for the Vero cells (20 microg/lml, i.e. 49 microM versus 90 microg/ml, i.e. 220 microM) indicating a higher cell growth inhibitory effect on the colon adenocarcinoma cells. At the respective IC50 concentrations, Rutaceline did not significantly induce apoptosis but induced cell cycle arrest in the GO/G1 phase, as well as a decrease of cells in S phase. Rutaceline also induced DNA fragmentation in both cell lines, as revealed by agarose gel electrophoresis, and a dose-dependent clastogenic effect in both cell lines as revealed by the Comet assay.

Phenazine 5,10-dioxide derivatives as hypoxic selective cytotoxins: Part II. Structure-activity relationship studies

The synthesis and evaluation as hypoxic selective cytotoxins of new derivatives of 2-amino or 2-hydroxyphenazine 5,10-dioxide are described. The compounds were developed as structural analogs of other bioreductive compounds and its in vitro cytotoxicities on V79 cells under hypoxic and aerobic conditions were determined. To gain insight into its mechanism of action electrochemical behavior, interaction with DNA experiments and QSAR studies were performed.

Design and evaluation of “3 + 1” mixed ligand oxorhenium and oxotechnetium complexes bearing a nitroaromatic group with potential application in nuclear medicine oncology

The synthesis and evaluation of a series of oxotechnetium and oxorhenium complexes containing a nitroaromatic moiety as potential radiopharmaceuticals for targeting tumour hypoxia is presented. 99mTc labelling was performed in high yield (>85%) and radiochemical purity (>90%). Their structure was corroborated by means of the rhenium complexes. Reduction potentials were in the range for bioreducible compounds. 99mTc complexes III-VI were selected for "in vivo" experiments in view of the results of cytotoxicity studies. Biodistribution in normal animals was characterized by high initial blood, lung and liver uptake, fast blood and soft tissue depuration and preferential excretion via the hepatobiliary system. Initial tumour uptake was moderate but tumour/muscle ratios for complexes III and IV, were favourable at all time points. Although the results are encouraging further development is still necessary in order to achieve higher tumour uptake and lower gastrointestinal activity.

A comparative study on the gastroduodenal tolerance of different antianaemic preparations

The most significant adverse effect of repeated oral administration of iron-containing antianaemic preparations is the gastroduodenal toxicity, attributable to a direct toxic effect of iron on the glandular epithelium. To assess gastroduodenal mucosal damage and the potential protective effect of different antianaemic preparations, a study was carried out to compare the gastroduodenal toxicity caused by three different types of antianaemic drugs in normal and anaemic rats administered at repeated therapeutic doses. Histological damage to the gastroduodenal mucosa was evaluated using light and electron microscopy. In both normal and anaemic rats, pathological changes were less marked in animals treated with ferrimannitol-ovoalbumin (TM/FMOA) than in those treated with iron protein succinylate or ferrous sulphate. Electron microscopic studies of duodenal mucosa in normal rats treated with iron protein succinylate and ferrous sulphate confirmed a severe ultrastructural alteration, whereas no changes were detected in animals treated with TM/FMOA. In anaemic rats, slight duodenal ultrastructural changes were noted with all three types of treatment. The effectiveness of the preparations in resolving the anaemia was similar in the three groups. It was concluded that TM/FMOA exerts a protective effect against the toxicity normally observed of the iron in other formulations in normal and anaemic rats, which was attributed to the fact that administration of iron bound to a protein core allows for gradual release of iron.