RESUMO
Polymeric nanocarriers (NCs) are efficient vehicles to prevent drug unspecific biodistribution and increase the drug amounts delivered to tumor tissues. However, some toxicological aspects of NCs still lack a comprehensive assessment, such as their effects on cellular processes that lead to toxicity. We evaluate the interaction of poly(lactic-co-glycolic acid) (PLGA) NCs prepared using dextran (Dex) and Pluronic®-F127 as stabilizing agents with myocardial cells (H9C2), breast adenocarcinoma cells (MCF-7) and macrophages (RAW 264.7) to address the effect of Dex in PLGA NC formulations. By an emulsion diffusion method, doxorubicin-loaded NCs were prepared with no Dex (PLGA-DOX), 1% (w/v) Dex (Dex1/PLGA-DOX) and 5% (w/v) Dex (Dex5/PLGA-DOX). Uptake analyses revealed a significant reduction in Dex5/PLGA-DOX NC uptake by H9C2 and MCF-7, as in the case of Dex1/PLGA-DOX NCs in the absence of in vitro protein corona, revealing an effect of dextran concentration on the formation of protein corona. RAW 264.7 cells presented a greater uptake of Dex5/PLGA-DOX NCs than the other NCs likely because of receptor mediated endocytosis, since C-type lectins like SIGN-R1, mannose receptors and scavenger receptor type 1 that are expressed in RAW 264.7 can mediate Dex uptake. Despite the lower uptake, Dex5/PLGA-DOX NCs promote the generation of reactive oxygen species and oxidative membrane damage in MCF-7 and H9C2 even though cellular metabolic activity assessed by MTT was comparable among all the NCs. Our results highlight the importance of an in-depth investigation of the NC-cell interaction considering additional mechanisms of damage apart from metabolic variations, as nanoparticle-induced damage is not limited to imbalance in metabolic processes, but also associated with other mechanisms, e.g., membrane and DNA damage.
Assuntos
Antineoplásicos , Coroa de Proteína , Humanos , Copolímero de Ácido Poliláctico e Ácido Poliglicólico/metabolismo , Dextranos , Portadores de Fármacos/metabolismo , Antineoplásicos/farmacologia , Distribuição Tecidual , Poloxâmero/metabolismo , Emulsões/metabolismo , Excipientes/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Doxorrubicina/farmacologia , Doxorrubicina/metabolismo , Membrana Celular/metabolismo , Lectinas Tipo C/metabolismoRESUMO
The vaginal mucosa is a very promising route for drug administration due to its high permeability and the possibility to bypass first pass metabolism; however, current vaginal dosage forms present low retention times due to their dilution in vaginal fluids, which hampers the efficacy of many pharmacological treatments. In order to overcome these problems, this study proposes to develop a mucoadhesive in situ gelling liquid crystalline precursor system composed of 30% of oleic acid and cholesterol (7:1), 40% of ethoxylated and propoxylated cetyl alcohol, and 30% of a dispersion of 16% Poloxamer 407. The effect of the dilution with simulated vaginal fluid (SVF) on this system was evaluated by polarized light microscopy (PLM), small-angle X-ray scattering (SAXS), rheological studies, texture profile analysis (TPA), mucoadhesion study, in vitro drug release test using hypericin (HYP) as drug model, and cytotoxicity assay. PLM and SAXS confirmed the formation of an isotropic system. After the addition of three different concentrations of SVF (30, 50, and 100%), the resultant formulations presented anisotropy and characteristics of viscous lamellar phases. Rheology shows that formulations with SVF behaved as a non-Newtonian fluid with suitable shear thinning for vaginal application. TPA and mucoadhesion assays indicated the formation of long-range ordered systems as the amount of SVF increases which may assist in the fixation of the formulation on the vaginal mucosa. The formulations were able to control about 75% of the released HYP demonstrating a sustained release profile. Finally, all formulations acted as safe vaginal drug delivery systems.
Assuntos
Administração Intravaginal , Géis/metabolismo , Mucosa/metabolismo , Animais , Líquidos Corporais , Cristalização , Sistemas de Liberação de Medicamentos , Liberação Controlada de Fármacos , Feminino , Poloxâmero/metabolismo , Reologia , Espalhamento a Baixo Ângulo , Vagina , Viscosidade , Difração de Raios XRESUMO
Nitric oxide (NO) releasing biomaterials represent a potential strategy for use as active wound dressings capable of accelerating wound healing. Topical NO-releasing poly(vinyl alcohol) (PVA) films and Pluronic F127 hydrogels (F127) have already exhibited effective skin vasodilation and wound healing actions. In this study, we functionalized PVA films with SNO groups via esterification with a mixture of mercaptosucinic acid (MSA) and thiolactic acid (TLA) followed by S-nitrosation of the SH moieties. These films were combined with an underlying layer of poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide), i.e., PEO-PPO-PEO (Pluronic F127) hydrogel and used for the topical treatment of skin lesions in an animal model. The mixed esterification of PVA with MSA and TLA led to chemically crosslinked PVA-SNO films with a high swelling capacity capable of spontaneously releasing NO. Real time NO-release measurements revealed that the hydrogel layer reduces the initial NO burst from the PVA-SNO films. We demonstrate that the combination of PVA-SNO films with F127 hydrogel accelerates wound contraction, decreases wound gap and cellular density and accelerates the inflammatory phase of the lesion. These results were reflected in an increase in myofibroblastic differentiation and collagen type III expression in the cicatricial tissue. Therefore, PVA-SNO films combined with F127 hydrogel may represent a new approach for active wound dressings capable of accelerating wound healing.
Assuntos
Hidrogéis/química , Óxido Nítrico/química , Poloxâmero/química , Álcool de Polivinil/química , Actinas/metabolismo , Animais , Antígenos de Diferenciação/metabolismo , Western Blotting , Hidrogéis/metabolismo , Hidrogéis/farmacologia , Imuno-Histoquímica , Masculino , Camundongos , Óxido Nítrico/metabolismo , Poloxâmero/metabolismo , Polietilenoglicóis/química , Polietilenoglicóis/metabolismo , Álcool de Polivinil/metabolismo , Álcool de Polivinil/farmacologia , Propilenoglicóis/química , Propilenoglicóis/metabolismo , S-Nitrosoglutationa/química , S-Nitrosoglutationa/metabolismo , Pele/metabolismo , Pele/patologia , Pele/fisiopatologia , Compostos de Sulfidrila/química , Tiomalatos/química , Fatores de Tempo , Cicatrização/efeitos dos fármacosRESUMO
The local delivery of nitric oxide (nitrogen monoxide, NO) by thermal or photochemical means to target cells or organs has a great potential in several biomedical applications, especially if the NO donors are incorporated into non-toxic viscous matrices. In this work, we have shown that the NO donors S-nitrosoglutathione (GSNO) and S-nitroso-N-acetylcysteine (SNAC) can be incorporated into F127 hydrogels, from where NO can be released thermally or photochemically (with lambda(irr)>480nm). High sensitivity differential scanning calorimetry (HSDSC) and a new spectrophotometric method, were used to characterize the micellization and the reversal thermal gelation processes of the F127 hydrogels containing NO donors, and to modulate the gelation temperatures to the range 29-32 degrees C. Spectral monitoring of the S-NO bond cleavage showed that the initial rates of thermal and photochemical NO release (ranging from 2 to 45 micromoll(-1)min(-1)) are decreased in the hydrogel matrices, relative to those obtained in aqueous solutions. This stabilization effect was assigned to a cage recombination mechanism and offers an additional advantage for the storage and handling of S-nitrosothiols. These results indicate that F127 hydrogels might be used for the thermal and photochemical delivery of NO from S-nitrosothiols to target areas in biomedical applications.