| Autor: |
da Silva GR; São Carlos Institute of Physics (IFSC), University of São Paulo (USP), São Paulo 13560-110, Brazil., Dos Santos AL; Nanomed-Innovation in Nanotechnology, São Paulo 13560-110, Brazil., Soares AC; São Carlos Institute of Physics (IFSC), University of São Paulo (USP), São Paulo 13560-110, Brazil.; Embrapa Instrumentation, São Paulo 13560-110, Brazil., Dos Santos MC; Chemical and Food School, Federal University of Rio Grande (FURG), Rio Grande 96203-000, Brazil., Dos Santos SC; Chemical and Food School, Federal University of Rio Grande (FURG), Rio Grande 96203-000, Brazil., Ţălu Ş; The Directorate of Research, Development and Innovation Management (DMCDI), Technical University of Cluj-Napoca, 15 Constantin Daicoviciu St., 400020 Cluj-Napoca, Romania., Rodrigues de Lima V; Chemical and Food School, Federal University of Rio Grande (FURG), Rio Grande 96203-000, Brazil., Bagnato VS; São Carlos Institute of Physics (IFSC), University of São Paulo (USP), São Paulo 13560-110, Brazil., Sanches EA; Laboratory of Nanostructured Polymers (NANOPOL), Federal University of Amazonas (UFAM), Manaus 69067-005, Brazil., Inada NM; São Carlos Institute of Physics (IFSC), University of São Paulo (USP), São Paulo 13560-110, Brazil. |
| Abstrakt: |
One of the most widely used molecules used for photodynamic therapy (PDT) is 5-aminolevulinic acid (5-ALA), a precursor in the synthesis of tetrapyrroles such as chlorophyll and heme. The 5-ALA skin permeation is considerably reduced due to its hydrophilic characteristics, decreasing its local bioavailability and therapeutic effect. For this reason, five different systems containing polymeric particles of poly [D, L-lactic-co-glycolic acid (PLGA)] were developed to encapsulate 5-ALA based on single and double emulsions methodology. All systems were standardized (according to the volume of reagents and mass of pharmaceutical ingredients) and compared in terms of laboratory scaling up, particle formation and stability over time. UV-VIS spectroscopy revealed that particle absorption/adsorption of 5-ALA was dependent on the method of synthesis. Different size distribution was observed by DLS and NTA techniques, revealing that 5-ALA increased the particle size. The contact angle evaluation showed that the system hydrophobicity was dependent on the surfactant and the 5-ALA contribution. The FTIR results indicated that the type of emulsion influenced the particle formation, as well as allowing PEG functionalization and interaction with 5-ALA. According to the 1 H-NMR results, the 5-ALA reduced the T1 values of polyvinyl alcohol (PVA) and PLGA in the double emulsion systems due to the decrease in molecular packing in the hydrophobic region. The results indicated that the system formed by single emulsion containing the combination PVA-PEG presented greater stability with less influence from 5-ALA. This system is a promising candidate to successfully encapsulate 5-ALA and achieve good performance and specificity for in vitro skin cancer treatment. |
