In vitro and In vivo toxicology evaluation to determine suitable biomedical Polymers for development of a papain-containing drug delivery system

Papain has been known by many decades for wounded tissues repair. However, papain stability is not high enough to be commercialized in a stable pharmaceutical form; therefore its use is limited. The strategy to entrap papain into a polymeric matrix to provide an adequate drug delivery system consists of an alternative to this problem. The purpose of this study was to assess in vitro and in vivo four polymers cytotoxicity and ability to cause cutaneous irritation to be applied as a suitable papain delivery system. A Monocomponent (MSD) and Bicomponent Silicone Dispersions (BSD) and, Natural Rubber Bicentrifuged Latex (NRBL) and an Acrylic Adhesive (AA) were selected. The cytotoxicity was firstly assessed by the Neutral Red Uptake Method. Non-cytotoxic polymers were then submitted to in vivo Cutaneous Irritation Test. Both silicone dispersions were found non-cytotoxic, and NRBL and AA polymers showed cytotoxicity. MSD and BSD polymers did not cause any cutaneous reactions.Colegio de Farmacéuticos de la Provincia de Buenos Aire

UVA and UVB formulation phototoxicity in a three-dimensional human skin model: photodegradation effect

In vitro three-dimensional human skin models are an innovative alternative to evaluate cytotoxicity and phototoxicity in the cosmetic industry. The aim of this study was to use a skin model to evaluate the potential toxicity of sunscreen formulations with or without exposure to UV radiation. In addition, the toxicity of these formulations was evaluated after exposure to photodegradation. The results showed toxicity with all formulations/conditions tested, including the control formulation, compared to PBS. Cell viability of photodegraded formulations - prior to the phototoxicity radiation process - was higher, indicating that some formulation components were degraded into products with reduced toxicity. The results also indicated that avobenzone was more unstable/toxic than octyl p-methoxycinnamate under the same test conditions. The sunscreens and their formulations were shown to be toxic to skin model cells to some extent, even when not exposed to UV irradiation; however the biological role of this toxicity is unclear. This result shows the importance of testing sunscreen formulations in real in-use conditions. Finally, since we used an in vitro assay based on a human cell model, this non-invasive technique represents a suitable alternative to animal models for phototoxicity tests in general and could have application in screening new sunscreen products

Study of the interaction of ionizing radiation in polyurethane polymer films as biomaterial

New materials are being studied and widely applied in the health area, highlighting biocompatible polymers as the most versatile. Among these polymers, we developed the methodology for the manufacture of Thermoplastic Polyurethane films for application as Biomaterials. The proposed sterilization by ionizing radiation requires the study and characterization of the material to evaluate possible losses or modifications, due to the influence that the radiation can cause in the polymer chains, losing the characteristics for the purpose used. Therefore, the present work evaluates, through chemical and physical-chemical characterization, the possible extension of the changes caused by the radiation in the polyurethane film. The material is produced in an environment with controlled temperature and humidity and subjected to increasing doses of gamma (15, 25 and 50 kGy), ethylene oxide and plasma as comparative techniques. The techniques DSC (Differential Scanning Calorimetry), TGA (Thermogravimetry), FTIR-ATR (Fourier Transform Infrared Spectrometry), SEM (Scanning electron microscopy) and OCT (Optical coherence tomography), have proved that the material, after applied the sterilization techniques, maintains its physical-chemical characteristics and does not suffer any modifications after the treatment

Autonomous growth of BALB/MK keratinocytes transfected with a retroviral vector carrying the human epidermal growth factor gene

Epidermal growth factor (EGF), which promotes epidermal regeneration and wound closure, is important for the proliferation and differentiation of epidermal and epithelial tissues in animals. Exogenous EGF is a promising therapeutic agent for wound healing, but its general use is restricted by the limited availability of this protein. in this work, we show that the transfection of mouse BALB/MK keratinocytes, which are totally dependent on EGF for growth and migration, with mature cDNA for human EGF via a retroviral vector abolished the cells requirement for exogenous EGF. the transformed cells had normal morphology and a growth rate that varied according to the source of the retroviral vector used. Keratinocyte transfection with EGF cDNA provides a time- and cost-efficient means of culturing keratinocytes and yields cells that may be useful for skin grafting

Radio-synthesized protein-based nanoparticles for biomedical purposes

Protein-crosslinking whether done by enzymatic or chemically induced pathways increases the overall stability of proteins. In the continuous search for alternative routes for protein stabilization we report a novel technique - radio-induced synthesis of protein nanoparticles - to achieve size controlled particles with preserved bioactivity. Papain was used as model enzyme and the samples were irradiated at 10. kGy in a gammacell irradiator in phosphate buffer (pH=7.0) and additives such as ethanol (0-40%) and sodium chloride (0-25%). The structural rearrangement caused by irradiation under defined conditions led to an increase in papain particle size as a function of the additive and its concentration. These changes occur due to intermolecular bindings, of covalent nature, possibly involving the aromatic amino acids. Ethanol held major effects over papain particle size and particle size distribution if compared to sodium chloride. The particles presented relative retained bioactivity and the physic-chemical characterization revealed similar fluorescence spectra indicating preserved conformation. Differences in fluorescence units were observed according to the additive and its concentration, as a result of protein content changes. Therefore, under optimized conditions, the developed technique may be applied for enzyme nanoparticles formation of controllable size and preserved bioactivity.Fil: Varca, Gustavo H. C.. Comissao Nacional de Energia Nuclear. Centro de Lasers e Aplicacoes. Instituto de Pesquisas Energéticas e Nucleares; BrasilFil: Ferraz, Caroline C.. Comissao Nacional de Energia Nuclear. Centro de Lasers e Aplicacoes. Instituto de Pesquisas Energéticas e Nucleares; BrasilFil: Lopes, Patricia S.. Universidade de Sao Paulo; BrasilFil: Mathor, Monica Beatriz. Comissao Nacional de Energia Nuclear. Centro de Lasers e Aplicacoes. Instituto de Pesquisas Energéticas e Nucleares; BrasilFil: Grasselli, Mariano. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Multidisciplinario de Biología Celular. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Multidisciplinario de Biología Celular. Universidad Nacional de La Plata. Instituto Multidisciplinario de Biología Celular; ArgentinaFil: Lugão, Ademar B.. Comissao Nacional de Energia Nuclear. Centro de Lasers e Aplicacoes. Instituto de Pesquisas Energéticas e Nucleares; Brasi

Radiation-grafting of thermo- and pH-responsive poly (N-vinylcaprolactam-co-acrylic acid) onto silicone rubber and polypropylene films for biomedical purposes

This work focuses on the effects of gamma-ray irradiation conditions on the stimuli-responsiveness of polypropylene (PP) films and silicone (SR) rubber substrates grafted with N-vinylcaprolactam (NVCL) and acrylic acid (AAc). PP films and SR rubber were modified by simultaneous polymerization and grafting of NVCL and AAc, using pre-irradiation oxidative method at a dose rate of 1223 kGy h(-1) and doses ranging from 5 to 70 kGy. NVCL and AAc solutions (1/1, v/v) at 50% monomer concentration (v/v) in toluene were added to the sample substrates, degassed, sealed and heated at 60 and 70 degrees C for 12 h. After grafting, the samples were soaked in ethanol and distilled water for 24 h successively, followed by drying under vacuum. Samples were characterized by FTIR-ATR, DSC and swelling measurements. Critical points (pH critical or LCST) of grafts were obtained in a pH-environment (pH ranges from 2.2 to 9) and in a thermo-environment (temperature ranges from 22 to 50 C). Cytotoxicity evaluation was performed using fibroblast BALB/c 3T3 cells. the relationship between NVCL-co-AAc grafting and radiation dose was different for each substrate, PP and SR. At 50% NVCL/AAc concentration in toluene, grafting values were higher for SR than for PP. Despite the fact that PP-g-(NVCL-co-AAc) membrane presented a cytotoxic profile at the highest experimental concentration assayed, cytotoxicity evaluation revealed noncytotoxic profiles for the membranes synthesized highlighting their applications for biomedical purposes. (C) 2013 Elsevier B.V. All rights reserved.DGAPA-UNAMConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Ibero-American Programme for Science, and Technology and Development of CYTEDInst Pesquisas Energet & Nucl IPEN CNEN SP, BR-05508000 São Paulo, BrazilUniv Nacl Autonoma Mexico, Inst Ciencias Nucl, Dept Quim Radiac & Radioquim, Mexico City 04510, DF, MexicoUniversidade Federal de São Paulo UNIFESP, BR-09913030 Diadema, SP, BrazilUniversidade Federal de São Paulo UNIFESP, BR-09913030 Diadema, SP, BrazilDGAPA-UNAM: IN202311CNPq: 174378Web of Scienc