PLGA-PEG nanoparticles containing gallium phthalocyanine: Preparation, optimization and analysis of its photodynamic efficiency on red blood cell and Hepa-1C1C7

Synergic Influence of Parameters Involved in the Polymeric Nanoparticle Preparation on the Efficacy of Photodynamic Therapy

“…However, the influence of a parameter used in a polymeric nanoparticles formulation will not always produce the same response for similar formulations. [5] There are significant challenges to consolidate polymeric nanoformulations in the pharmaceutical market since small changes in the composition of the formulation, for example, the encapsulated drug, can influence the nanoparticles properties, such as the particle size, the surface charge, the residual amount of emulsifier on the surface of the particles, and encapsulation and recovery efficiencies of the nanoparticles. [5]…”

“…For example, in intravenous administration, the particles must be smaller than 5 μm in order to circulate through the capillaries, however, smaller sizes are necessary for nanoparticles reach the tumor vessels and remain longer in the blood stream. [5,8,22] Researches have shown that nanoparticles with sizes smaller than 200 nm have a longer circulation time in the bloodstream due to the reduction of the recognition of the nanoparticle by plasma proteins (opsonin) that signal the reticuloendothelial system to act in the phagocytosis process of the nanoparticles. Remaining longer in the circulatory system, smaller diameter particles could interact more effectively with cell membranes, presenting greater capacity of cellular internalization due to the overexpression of porous in tumor cells membranes, a fact that would result in greater efficiency of nanoparticulate photosensitizers in reducing cell viability through PDT.…”

“…Photodynamic therapy (PDT) is an important therapeutic modality used in the treatment of cancer and several non-malignant diseases, including infections and dental treatments. [1][2][3][4][5] It is characterized by the administration of a photosensitizer (PS), a light source to activate it and oxygen molecules (Figure 1). [6] After administration of the photosensitizer, the diseased tissue is irradiated Photodynamic Therapy -From Basic Science to Clinical Research with visible light, causing the excitation of the PS to a singlet electronic state (S 1 ), which can be deactivated to the fundamental state (S 0 ) through radiative processes (fluorescence or phosphorescence) or non-radioactive (internal conversion, intersystem crossing or vibrational relaxation).…”

“…[15] PDT mechanism involving the combination of a photosensitizer, a light source and oxygen molecules. After excitation to a higher energy state (1), the photosensitizer may suffer rotovibrational decays to the excited state S 1 (2), from which the photosensitizer can suffer energy decay to the fundamental state S 0 , via fluorescence (3), intersystem crossing (4) or phosphorescence (5).…”

“…[15] However, it also be reported that the use of nanomaterials in contemporary clinical practice need to be monitored because of the unpredicted effects of the cumulative exposes of non-biodegradable nanoparticle in the human body. [19] Few nanoparticulate formulations are on the shelves of pharmacies due to the lack of knowledge of the combinatorial influence of the parameters used in the preparation of the nanoparticles on the fundamental properties for maximum therapeutic potential, [5] a fact that hampers the scale up process for the production of nanoparticulate formulations. Besides, the poor batch-to batch reproducibility to prepare polymeric nanoparticle, the low solubility of some polymers in water that requires the use of organic solvent to synthesize the nanoparticle, the low glass transition temperature of some polymers that limit the use of them to prepare the nanoparticulate formulation and the high cost of biodegradable polymers are drawback that hamper the development of nanoparticulate pharmaceutic formulation for using in PDT.…”