Copolymer-nanocapsules of zinc phenyl-thio-phthalocyanine and amphotericin-B in association with antimicrobial photodynamic therapy (A-PDT) applications against Candida albicans yeasts.

Antimicrobial Photodynamic Therapy (A-PDT) is a modern and non-invasive therapeutic modality. Nanostructures like the polymeric nanocapsules (NC) has proved to be a system that has enormous potential to improve current antimicrobial therapeutic practice. NC of Zinc phenyl-thio-phthalocyanine and Amphotericin B association (NC/ZnS4Pc + AMB) built with poly(lactide-co-glycolide) (PLGA) 50:50 using the preformed polymer interfacial deposition method were developed at a 0.05 mg mL- 1 theoretical concentration to improve antifungal activity with two actives association and assistance from PDTa. It showed an average particle diameter of 253.8 ±â€¯17.3, an average polydispersity index of 0.36 ±â€¯0.01, and a negative Zeta potential average of -31.03 ±â€¯5.54 for 158 days. UV-vis absorption and emission spectroscopy analyses did not show changes in photophysical properties in the steady-state of NC/ZnS4Pc + AMB counterparts free ZnS4Pc. The encapsulation percentage of actives was 89.24 % and 7.40 % for ZnS4Pc and AMB, respectively. Cell viability assay using NIH/3T3 ATCC® CRL-1658 ™ cells line showed no cytotoxicity for the concentrations tested. The photodynamic activity assay using NC/ZnS4Pc + AMB diluted showed fungal toxicity against Candida albicans yeast with energetic fluences of 12 J.cm-2 and 25 J.cm-2 by a decrease in cell viability. The MFC assay demonstrated a fungistatic activity for the conditions employed in the PDTa assay. The results show that NC/ZnS4Pc + AMB is a promising nanomaterial for antimicrobial inactivation using PDT.

A long-term controlled drug-delivery with anionic beta cyclodextrin complex in layer-by-layer coating for percutaneous implants devices.

This study demonstrated a drug-delivery system with anionic beta cyclodextrin (ß-CD) complexes to retain tetracycline (TC) and control its release from multilayers of poly(acrylic acid) (PAA) and poly(l-lysine) (PLL) in a ten double layers ([PAA/PLL]10) coating onto titanium. The drug-delivery capacity of the multilayer system was proven by controlled drug release over 15 days and sustained released over 30 days. Qualitative images confirmed TC retention within the layer-by-layer (LbL) over 30 days of incubation. Antibacterial activity of TC/anionic ß-CD released from the LbL was established against Staphylococcus aureus species. Remarkably, [PAA/PLL]10/TC/anionic ß-CD antibacterial effect was sustained even after 30 days of incubation. The non-cytotoxic effect of the multilayer system revealed normal human gingival fibroblast growth. It is expected that this novel approach and the chemical concept to improve drug incorporation into the multilayer system will open up possibilities to make the drug release system more applicable to implantable percutaneous devices.

Interaction of guar gum galactomannans with the anionic surfactant sodium lauryl ether sulphate.

The interaction between galactomannans, guar gum (GG) with sodium lauryl ether sulphate (SLES) was demonstrated using conductometric, tensiometric, pyrene probe and 1H NMR analyses. SLES and GG formed aggregates and reduced the surface tension at a critical aggregation concentration. The interaction was attributed to the presence of surfactant ethoxyl (EO) groups, since in conductometric, tensiometry and pyrene probe analyses using the non-ethoxylated form, sodium lauryl sulphate - SLS, no aggregation was observed. The aggregates formed between SLES and GG presented a negative zeta potential indicating that the polymer is surrounded by SLES and according to the dynamic light scattering analysis (DLS), presented a size of approximately 26 nm. The determination of the thermodynamic parameters showed that the aggregation occurs spontaneously and is a driven-enthalpy and entropy process. SLES and GG interaction could be explored to produce formulations with lower concentrations of surfactants, using commonly used thickeners as GG.