Skin permeation, biocompatibility and antitumor effect of chloroaluminum phthalocyanine associated to oleic acid in lipid nanoparticles.

The objective of this study was to develop and characterize lipid nanoparticles (LNs) containing chloroaluminum phthalocyanine (ClAlPc) to reduce the aggregation of the drug and improve its skin penetration and its antitumor effect. LNs were prepared and characterized by using stearic acid (SA) as solid lipid and oleic acid (OA) as liquid lipid in different proportions. in vitro and in vivo skin penetration was evaluated using modified Franz diffusion cells and fluorescence microscopy, respectively. in vitro biocompatibility and Photodynamic Therapy (PDT) were performed using L929-fibroblasts cell line and A549 cancer cell line and melanoma BF16-F10, respectively. OA promoted the increase in the encapsulation efficiency and drug loading, reaching values of 95.8% and 4%, respectively. The formulation with 40% OA (NLC 40) showed a significantly higher (p < 0.01) amount of drug retained in the skin compared to other formulations. All formulations developed were considered biocompatible. PDT evidenced the antitumor efficacy of NLC 40 with reduced cell viability for approximately 10% of cancer cells, demonstrating that the presence of OA in the NLC seems to potentialize this antitumor effect. PDT in BF16-F10 melanoma using NLC 40 resulted in a reduction in mean cell viability of approximately 99%. According to the results obtained, the systems developed may be promising for the incorporation of ClAlPc in the treatment of skin cancer by photodynamic therapy.

Thermally stimulated luminescence and EPR studies on topaz.

In the present work, electron paramagnetic resonance (EPR) spectra and thermoluminescence (TL) emission of colourless natural topaz from Santo Antônio do Jacinto, Brazil, was studied as a function of thermal treatment and gamma irradiation dose, focussing on the use of this material as a radiation dosimeter. EPR measurements on "as-received" samples at room temperature provided signals in the region of about 500 at 5,000 G. The signal located around g approximately equal to 2, frequently attributed to (AlO(4))(0), increased with additional gamma dose and disappeared after thermal treatment at 500 degrees C for 1h. Irradiation after thermal treatment recovered this signal. The decay promoted by isochronal thermal treatment showed the (AlO(4))(0) defects to be directly related to the TL glows peaks. The variation of EPR spectrum with annealing temperature prior to irradiation showed that the variation of TL sensitivity is a consequence of the variation of the (AlO(4))(0) population.

Evaluation of doses in radiotherapy using solid-state composites based on natural colourless topaz.

The thermoluminescent properties of composites containing powdered topaz embedded in Teflon or glass were studied and compared with the corresponding properties of the well known TLD-100 commercial dosimeters. Relative sensitivity, TL fading, reproducibility of the sample preparation process, and possibility of re-utilisation of the dosimeters were investigated. Measurements of absorbed doses in simulated radiotherapy treatments were also taken. The irradiations were performed using gamma rays from a 60Co source in the dose range from 1cGy to 2Gy. The dosimeters were installed in badges and attached inside acrylic plates of various thicknesses in the radiation fields. The dose profiles obtained with this procedure are very similar to the ones obtained with equivalent tissues. It is concluded that these composites of natural colourless topaz crystals can be efficiently used as TL dosimeters.