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1.
Eur J Pharm Sci ; 166: 105985, 2021 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-34455087

RESUMO

Non-ideal behaviour of mixed ions is disclosed in skin absorption experiments of mixed halide anions in excised pig skin. Comparison of skin absorption of pure and mixed ions shows enhanced penetration of chaotropic ions from mixed solutions. An experimental design and statistical analysis using a Scheffé {3,2} simplex-lattice allows investigating the full ternary diagram of anion mixtures of fluoride, bromide and iodide. Synergism in mixed absorption is observed for chaotropic bromide and iodide anions. A refined analysis highlighting specific interactions is made by considering the ratio of the absorbed amount to the ion activity instead of the directly measured absorbed amount. Statistical analysis discards non-significant effects and discloses specific interactions. Such interactions between bromide and iodide cause an absorption enhancement of their partner by a factor of 2-3 with respect to the case of ideal mixing. It is proposed that enhanced absorption from mixed solution involves the formation of neutral complex species of mixed bromide and iodide with endogenous magnesium or calcium inside stratum corneum.


Assuntos
Absorção Cutânea , Água , Animais , Ânions/metabolismo , Fluoretos/metabolismo , Pele/metabolismo , Soluções , Suínos , Água/metabolismo
2.
Int J Cosmet Sci ; 43(4): 432-445, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-33964042

RESUMO

OBJECTIVE: Pickering emulsions are increasingly used in the pharmaceutical and cosmetic fields, especially for topical applications, since these systems require solid particles as emulsifiers instead of surfactants which are known to cause skin irritation. The solid inorganic nanoparticles (TiO2 and ZnO) used as UV filters in sunscreen formulations may also stabilize emulsion droplets, so that the utility of surfactants may be questioned. Surfactant-free sunscreen emulsions solely stabilized by such nanoparticles (NPs) have been studied. METHODS: The ability of these NPs to stabilize o/w emulsions containing a 'model' oil phase, the C12 -C15 alkylbenzoate, has been assessed. ZnO and hydrophilic silica-coated TiO2 NPs widely used in sunscreen products were used together with their mixtures. The emulsification efficiency, the control of droplet size and the stability of o/w Pickering emulsions solely stabilized by NPs were investigated. A ZnO/TiO2 NPs mixture characterized by a theoretical SPF of 45 was finally used as unique emulsifiers to develop a surfactant-free sunscreen emulsion. RESULTS: Stable Pickering emulsions containing 10 up to 60 wt% of C12 -C15 alkyl benzoate were formulated with 2 wt% ZnO in the aqueous phase. The droplet size was controlled by the solid NPs content with respect to oil and the emulsification process. Hydrophilic TiO2 NPs did not allow the stabilization of emulsions. The substitution of TiO2 for ZnO up to 60-70 wt% in a 20/80 o/w emulsion was successfully performed. Finally, a ZnO/TiO2 NP mixture was tested as unique emulsifier system for the formulation of a sunscreen cream. Despite a lower viscosity, the obtained Pickering emulsion was stable and exhibited a photoprotective effect similar to the corresponding surfactant-based sunscreen cream with an in vitro SPF of about 45. CONCLUSION: Surfactant-free Pickering emulsions can be stabilized by the UV-filter nanoparticles for the manufacture of sunscreen products.

3.
Int J Pharm ; 592: 120092, 2021 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-33212173

RESUMO

Emulsified systems are widely used for topical delivery with the aim of optimizing cutaneous absorption and offering a pleasant sensory. They also may provide a protection of the active molecule against oxidation and/or degradation. The oil phase of o/w emulsions may consist of liquid crystalline structures, especially lamellar structures which are similar to those found in the stratum corneum lipids. In the present work, o/w emulsions containing liquid crystals of mixed cetyl alcohol and Polysorbate 60 were developed for topical delivery of vitamin C, a potent antioxidant with several applications in the cosmetic and pharmaceutical fields. In addition to the well-documented lipid supplementation of the stratum corneum, the liquid crystal emulsions provide a significant chemical stabilization of vitamin C against its degradation. Emulsions were characterized by X-ray diffraction, polarized optical microscopy, and transmission electron microscopy. The stability of vitamin C in the formulations was evaluated upon storage in different conditions of temperature. The emulsions contain a complex colloidal structure, consisting of lamellar liquid crystalline (Lα) and crystalline lamellar gel (Lß) phases, that provide a very efficient protection of vitamin C against its degradation.


Assuntos
Cosméticos , Cristais Líquidos , Ácido Ascórbico , Emulsões , Absorção Cutânea
4.
Int J Pharm ; 591: 119991, 2020 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-33091552

RESUMO

Skin constitutes a barrier protecting the organism against physical and chemical factors. Therefore, it is constantly exposed to the xenobiotics, including inorganic ions that are ubiquitous in the environment. Some of them play important roles in homeostasis and regulatory functions of the body, also in the skin, while others can be considered dangerous. Many authors have shown that inorganic ions could penetrate inside the skin and possibly induce local effects. In this review, we give an account of the current knowledge on the effects of skin exposure to inorganic ions. Beneficial effects on skin conditions related to the use of thermal spring waters are discussed together with the application of aluminium in underarm hygiene products and silver salts in treatment of difficult wounds. Finally, the potential consequences of dermal exposure to topical sensitizers and harmful heavy ions including radionuclides are discussed.


Assuntos
Absorção Cutânea , Pele , Íons/metabolismo , Prata/metabolismo , Pele/metabolismo
5.
Int J Pharm ; 583: 119373, 2020 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-32339629

RESUMO

For several years, the international context is deeply affected by the use of chemical and biological weapons. The use of CBRN (Chemical Biological Radiological Nuclear) threat agents from military stockpiles or biological civilian industry demonstrate the critical need to improve capabilities of decontamination for civilians and military. Physical decontamination systems that operate only by adsorption and displacement such as Fuller's Earth, have the drawback of not neutralizing hazardous agents, giving place to cross contaminations. Consequently, the development of a formulation based on metal oxide nanoparticles attracts considerable interest, since they offer physicochemical properties that allow them to both adsorb and degrade toxic compounds. Thus, the aim of this study is to found metal oxide nanoparticles with a versatile activity on both chemical and biological toxic agents. Therefore, several metal oxides such as MgO, TiO2, CeO2, ZnO and ZrO2 were characterized and their decontamination kinetics of less-toxic surrogate of VX, paraoxon, were studied in vitro. To determine the antimicrobial activity of these nanoparticles, simulants of biological terrorist threat were used by performing a 3-hours decontamination kinetics. This proof-of-concept study showed that MgO is the only one that exhibits both chemical and antibacterial actions but without sporicidal activity.


Assuntos
Antibacterianos/farmacologia , Bactérias/efeitos dos fármacos , Armas Biológicas , Substâncias para a Guerra Química/toxicidade , Descontaminação , Óxido de Magnésio/farmacologia , Nanopartículas Metálicas , Paraoxon/toxicidade , Antibacterianos/química , Bactérias/crescimento & desenvolvimento , Cério/farmacologia , Substâncias para a Guerra Química/química , Hidrólise , Cinética , Óxido de Magnésio/química , Modelos Químicos , Paraoxon/química , Estudo de Prova de Conceito , Titânio/farmacologia , Óxido de Zinco/farmacologia , Zircônio/farmacologia
6.
Int J Pharm ; 563: 79-90, 2019 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-30825557

RESUMO

We present a systematic study of the role of poly(ethylene glycol) (PEG) content in NPs on drug skin absorption. Cholecalciferol-loaded NPs of 100 nm of diameter were prepared by flash nanoprecipitation from PLA-b-PEG copolymers of various PEG lengths. As PEG content increased in the polymer, we observed a transition from a frozen solid particle structure to a more dynamic particle structure. Skin absorption studies showed that polymer composition influenced drug penetration depending on skin condition (intact or impaired). In intact skin, highly PEGylated NPs achieved the best skin absorption, even if the penetration differences between the NPs were low. In impaired skin, on the contrary, non-PEGylated NPs (PLA NPs) promoted a strong drug deposition. Further investigations revealed that the strong drug accumulation from PLA NPs in impaired skin was mediated by aggregation and sedimentation of NPs due to the release of charged species from the skin. In contrast, the dynamic structure of highly PEGylated NPs promoted wetting of the surface and interactions with skin lipids, improving drug absorption in intact skin. Since NPs structure and surface properties determine the drug penetration mechanisms at the NP-skin interface, this work highlights the importance of properly tuning NPs composition according to skin physiopathology.


Assuntos
Colecalciferol/administração & dosagem , Lactatos/administração & dosagem , Nanopartículas/administração & dosagem , Polietilenoglicóis/administração & dosagem , Absorção Cutânea , Pele/metabolismo , Animais , Colecalciferol/química , Feminino , Técnicas In Vitro , Lactatos/química , Peso Molecular , Nanopartículas/química , Polietilenoglicóis/química , Pele/lesões , Suínos
7.
Phys Chem Chem Phys ; 21(10): 5455-5465, 2019 Mar 06.
Artigo em Inglês | MEDLINE | ID: mdl-30801105

RESUMO

Repeated attacks using organophosphorus compounds, in military conflicts or terrorist acts, necessitate developing inexpensive and readily available decontamination systems. Nanosized cerium oxide is a suitable candidate, acting as a heterogeneous catalyst for the degradation of organophosphorus compounds such as VX agent or sarin. However, the reaction mechanism of the phosphatase mimetic activity of CeO2 nanoparticles is not fully described. Adsorption, surface-promoted hydrolysis, and desorption cycles strongly depend on the physico-chemical characteristics of the facets. In this study, CeO2 nanoparticles with different shapes were elaborated by hydrothermal synthesis. Nano-octahedra, nanocubes, or nanorods were selectively obtained under different conditions (temperature, concentration and nature of the precursors). The degradation activity according to the crystal faces was evaluated in vitro by measuring the degradation kinetics of paraoxon organophosphate in the presence of CeO2 nanoparticles. The results show an influence of both specific surface area and crystal faces of the nanoparticles, with higher activity for {111} facets compared to {100} facets at 32 °C. The relative activity between the facets is ascribed to the adsorption probability, assuming coordination between the phosphoryl oxygen and cerium atoms, but also to the surface density of the Ce doublets with relevant spacing for phosphatase mimetic activity.

8.
Int J Pharm ; 553(1-2): 120-131, 2018 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-30316003

RESUMO

We investigated the influence of nanoparticle (NP) surface composition on different aspects of skin delivery of a lipophilic drug: chemical stability, release and skin penetration. Cholecalciferol was chosen as a labile model drug. Poly(lactic acid) (PLA)-based NPs without surface coating, with a non-ionic poly(ethylene glycol) (PEG) coating, or with a zwitterionic poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC) coating were prepared using flash nanoprecipitation. Process was optimized to obtain similar hydrodynamic diameters. Polymeric NPs were compared to non-polymeric cholecalciferol formulations. Cholecalciferol stability in aqueous medium was improved by polymeric encapsulation with a valuable effect of a hydrophilic coating. However, the in vitro release of the drug was found independent of the presence of any polymer, as for the drug penetration in an intact skin model. Such tendency was not observed in impaired skin since, when stratum corneum was removed, we found that a neutral hydrophilic coating around NPs reduced drug penetration compared to pure drug NPs and bare PLA NPs. The nature of the hydrophilic block (PEG or PMPC) had however no impact. We hypothesized that NPs surface influenced drug penetration in impaired skin due to different electrostatic interactions between NPs and charged skin components of viable skin layers.


Assuntos
Colecalciferol/administração & dosagem , Sistemas de Liberação de Medicamentos , Nanopartículas , Polímeros/química , Administração Cutânea , Animais , Química Farmacêutica/métodos , Colecalciferol/farmacocinética , Portadores de Fármacos/química , Estabilidade de Medicamentos , Feminino , Interações Hidrofóbicas e Hidrofílicas , Tamanho da Partícula , Fosforilcolina/análogos & derivados , Fosforilcolina/química , Poliésteres/química , Polietilenoglicóis/química , Ácidos Polimetacrílicos/química , Absorção Cutânea , Eletricidade Estática , Suínos
9.
Int J Pharm ; 550(1-2): 170-179, 2018 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-30118832

RESUMO

Clinical use of calcitriol (1,25-dihydroxyvitamin D3) as an anticancer agent is currently limited by the requirement of supraphysiological doses and associated hypercalcemia. Nanoencapsulation of calcitriol is a strategy to overcome these drawbacks, allowing reduced administrated doses and/or frequency, while retaining the therapeutic activity towards cancer cells. For this purpose, we investigated the impact of calcitriol encapsulation on its antiproliferative activity and optimized formulation parameters with that respect. Calcitriol-loaded polymeric nanoparticles with different polymer:oil ratios were prepared by the nanoprecipitation method. Nanoparticles had similar mean size (200 nm) and EE (85%) whereas their release profile strongly depended on formulation parameters. Antiproliferative and cytotoxic activities of formulated calcitriol were evaluated in vitro using human breast adenocarcinoma cells (MCF-7) and showed that calcitriol-induced cell growth inhibition was closely related to its release kinetics. For the most suitable formulation, a sustained cell growth inhibition was observed over 10 days compared to free form. Advantages of calcitriol encapsulation and the role of formulation parameters on its biological activity in vitro were demonstrated. Selected nanoparticle formulation is a promising calcitriol delivery system ensuring a prolonged anticancer activity that could improve its therapeutic efficiency.


Assuntos
Antineoplásicos/farmacologia , Neoplasias da Mama/tratamento farmacológico , Calcitriol/farmacologia , Portadores de Fármacos , Nanocápsulas , Polímeros , Antineoplásicos/uso terapêutico , Calcitriol/uso terapêutico , Proliferação de Células/efeitos dos fármacos , Feminino , Humanos , Células MCF-7 , Nanocápsulas/química
10.
Int J Pharm ; 531(1): 134-142, 2017 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-28802793

RESUMO

Surfactant-free biocompatible and biodegradable Pickering emulsions were investigated as vehicles for skin delivery of hydrophobic drugs. O/w emulsions of medium-chain triglyceride (MCT) oil droplets loaded with all-trans retinol as a model hydrophobic drug were stabilized by block copolymer nanoparticles: either poly(lactide)-block-poly(ethylene glycol) (PLA-b-PEG) or poly(caprolactone)-block-poly(ethylene glycol) (PCL-b-PEG). Those innovative emulsions were prepared using two different processes allowing drug loading either inside oil droplets or inside both oil droplets and non-adsorbed block copolymer nanoparticles. Skin absorption of retinol was investigated in vitro on pig skin biopsies using the Franz cell method. Supplementary experiments by confocal fluorescence microscopy allowed the visualization of skin absorption of the Nile Red dye on histological sections. Retinol and Nile Red absorption experiments showed the large accumulation of hydrophobic drugs in the stratum corneum for the Pickering emulsions compared to the surfactant-based emulsion and an oil solution. Loading drug inside both oil droplets and block copolymer nanoparticles enhanced again skin absorption of drugs, which was ascribed to the supplementary contribution of free block copolymer nanoparticles loaded with drug. Such effect allowed tuning drug delivery to skin over a wide range by means of a suitable selection of either the formulation or the drug loading process.


Assuntos
Portadores de Fármacos/química , Emulsões/química , Absorção Cutânea , Animais , Etilenoglicóis , Lactatos , Micelas , Poliésteres , Polietilenoglicóis , Suínos
11.
Int J Radiat Biol ; 93(6): 607-616, 2017 06.
Artigo em Inglês | MEDLINE | ID: mdl-28276896

RESUMO

PURPOSE: To evaluate skin penetration and retention of americium (Am) and plutonium (Pu), in different chemical forms relevant to the nuclear industry and to treatment by chelation. MATERIALS AND METHODS: Percutaneous penetration of different Am and Pu forms were evaluated using viable pig skin with the Franz cell diffusion system. The behavior of the complex Pu-tributyl phosphate (Pu-TBP), Am or Pu complexed to the chelator Diethylene triamine pentaacetic acid (DTPA) and the effect of dimethyl sulfoxide (DMSO) was assessed. Radioactivity was measured in skin and receiver compartments. Three approaches were used to visualize activity in skin including the recent iQID technique for quantification. RESULTS: Transfer of Am was 24-fold greater than Pu and Pu-TBP complex penetration was enhanced by 500-fold. Actinide-DTPA transfer was greater than the Am or Pu alone (17-fold and 148-fold, respectively). The stratum corneum retained the majority of activity in all cases and both DMSO and TBP enhanced skin retention of Am and Pu, respectively. Histological and bioimaging data confirmed these results and the iQID camera allowed the quantification of skin activity. CONCLUSIONS: Skin penetration and fixation profiles are different depending on the chemical actinide form. Altered behavior of Pu-TBP and actinide-DTPA complexes reinforces the need to address decontamination protocols.


Assuntos
Elementos da Série Actinoide/farmacocinética , Quelantes/administração & dosagem , Absorção Cutânea/fisiologia , Pele/efeitos dos fármacos , Pele/metabolismo , Solventes/administração & dosagem , Absorção de Radiação/efeitos dos fármacos , Absorção de Radiação/fisiologia , Administração Tópica , Animais , Terapia por Quelação/métodos , Descontaminação/métodos , Técnicas In Vitro , Absorção Cutânea/efeitos dos fármacos , Suínos , Distribuição Tecidual/efeitos dos fármacos
12.
Chem Biol Interact ; 267: 57-66, 2017 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-27129420

RESUMO

Organophosphorus compounds (OP), which mainly penetrate via the percutaneous pathway, represent a threat for both military and civilians. Body surface decontamination is vital to prevent victims poisoning. The development of a cost-effective formulation, which could be efficient and easy to handle in case of mass contamination, is therefore crucial. Metal oxides nanoparticles, due their large surface areas and the large amount of highly reactive sites, present high reactivity towards OP. First, this study aimed at evaluating the reaction of CeO2 nanoparticles, synthetized by microwave path and calcined at 500 or 600 °C, with Paraoxon (POX) in aqueous solution. Results showed that both nanoparticles degraded 60%-70% of POX. CeO2 calcined at 500 °C, owing to its larger specific area, was the most effective. Moreover, the degradation was significantly increased under Ultra-Violet irradiation (initial degradation rate doubled). Then, skin decontamination was studied in vitro using the Franz cell method with pig-ear skin samples. CeO2 powder and an aqueous suspension of CeO2 (CeO2-W) were applied 1 h after POX exposure. The efficiency of decontamination, including removal and/or degradation of POX, was compared to Fuller's earth (FE) and RSDL lotion which are, currently, the most efficient systems for skin decontamination. CeO2-W and RSDL were the most efficient to remove POX from the skin surface and decrease skin absorption by 6.4 compared to the control not decontaminated. FE reduced significantly (twice) the absorbed fraction of POX, contrarily to CeO2 powder. Considering only the degradation rate of POX, the products ranged in the order CeO2 > RSDL > CeO2-W > FE (no degradation). This study showed that CeO2 nanoparticles are a promising material for skin decontamination of OP if formulated as a dispersion able to remove POX like CeO2-W and to degrade it as CeO2 powder.


Assuntos
Cério/química , Descontaminação/métodos , Nanopartículas Metálicas/química , Paraoxon/toxicidade , Praguicidas/toxicidade , Pele/efeitos dos fármacos , Compostos de Alumínio/farmacologia , Animais , Cromatografia Líquida de Alta Pressão , Compostos de Magnésio/farmacologia , Nanopartículas Metálicas/ultraestrutura , Paraoxon/análise , Praguicidas/análise , Fotólise/efeitos da radiação , Silicatos/farmacologia , Pele/patologia , Creme para a Pele/farmacologia , Espectrofotometria Ultravioleta , Suínos , Raios Ultravioleta
13.
Soft Matter ; 12(36): 7564-76, 2016 Sep 28.
Artigo em Inglês | MEDLINE | ID: mdl-27510805

RESUMO

The stabilization of o/w Pickering emulsions in cases of weak adsorption of solid particles at the surface of oil droplets is addressed. Though the adsorption is usually very strong and irreversible when partial wetting conditions are fulfilled, electrostatic repulsions between charged solid particles act against the adsorption. The regime of weak adsorption was reached using charged silica nanoparticles at high pH and low ionic strength. O/w Pickering emulsions of the diisopropyl adipate oil were stabilized by colloidal nanoparticles of Ludox® AS40 consisting of non-aggregated particles of bare silica (hydrophilic). The combination of stability assessment, droplet size and electrokinetic potential measurements at various pH values, adsorption isotherms and cryo-SEM observations of the adsorbed layers disclosed the specificities of the stabilization of Pickering emulsions by adsorption of solid nanoparticles against strong electrostatic repulsions. Not only the long-term stability of emulsions was poor under strong electrostatic repulsions at high pH, but emulsification failed since full dispersion of oil could not be achieved. Emulsion stability was ensured by decreasing electrostatic repulsions by lowering the pH from 9 to 3. Stable emulsions were stabilized by a monolayer of silica particles at 54% coverage of the oil droplet surface at low silica content and an adsorption regime as multilayers was reached at higher concentrations of silica although there was no aggregation of silica in the bulk aqueous phase.

14.
Pharm Res ; 33(7): 1564-75, 2016 07.
Artigo em Inglês | MEDLINE | ID: mdl-27015843

RESUMO

PURPOSE: Measurement of skin absorption of ions requires specific experimental protocols regarding the use of pig skin as a model, the viability of excised skin in water medium over 24 h, the presence of endogenous ions, and evaluation of the contributions of facilitated transport through ion channels and ion transporters. METHOD: Absorption experiments of halide anions F(-), Cl(-), Br(-) and I(-) in excised skin were performed in Franz diffusion cells. Experiments were performed on human and porcine skin under various conditions so as to define and validate experimental protocols. RESULTS: The distributions of endogenous ions and the absorption kinetics of halide ions were similar in both porcine and human skin models. Fresh skin kept its viability over 24 h in salt-free water, allowing experiments following OECD guidelines. Permeation increased in the order F(-) < Cl(-) < Br(-) < I(-) for all receptor media and skin samples. Absorption was larger in fresh skin due to the transport through chloride channels or exchangers. CONCLUSION: Skin absorption experiments of ions in Franz cells rely on working with fresh excised skin (human or porcine) and pure water as receptor fluid. Experiments with chloride blockers or frozen/thawed skin allow discriminating passive diffusion and facilitated transport.


Assuntos
Ânions/metabolismo , Absorção Cutânea/fisiologia , Pele/metabolismo , Animais , Difusão , Feminino , Humanos , Cinética , Masculino , Suínos , Água/metabolismo
15.
Pharm Res ; 33(7): 1576-86, 2016 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-27001272

RESUMO

PURPOSE: The purpose of the study was to sort skin penetration of anions with respect to their properties and to assess their mechanisms of penetration. METHODS: Aqueous solutions of halides at two concentrations were prepared and quantitative penetration studies were carried out for 24 h using Franz diffusion cells. The iodide permeation was also measured after blocking of anion channels and transporters to investigate the role of this specific transport. RESULTS: Absorption of halide ions into skin revealed large differences of transport between these anions according to the Hofmeister series. Increasing steady-state fluxes and lag times in the order F(-) < Cl(-) < Br(-) < I(-) were observed in permeation experiments. The steady-state fluxes were proportional to the concentration for each halide ion. Longer lag times for iodide or bromide ions were explained by the ability of such sticky chaotropic anions to interact with apolar lipids especially in the stratum corneum. Inhibiting ion exchangers and channels decreased the flux of iodide ions by 75%, showing the high contribution of the facilitated transport over the passive pathway. CONCLUSION: Ions transport had contributions coming from passive diffusion through the skin layers and transport mediated by ion channels and binding to ion transporters.


Assuntos
Ânions/metabolismo , Absorção Cutânea/fisiologia , Pele/metabolismo , Animais , Difusão , Feminino , Íons/metabolismo , Masculino , Suínos
16.
Toxicol In Vitro ; 34: 45-54, 2016 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-27021875

RESUMO

This study aimed at developing innovative systems for skin decontamination. Pickering emulsions, i.e. solid-stabilized emulsions, containing silica (S-PE) or Fuller's earth (FE-PE) were formulated. Their efficiency for skin decontamination was evaluated, in vitro, 45min after an exposure to VX, one of the most highly toxic chemical warfare agents. Pickering emulsions were compared to FE (FE-W) and silica (S-W) aqueous suspensions. PE containing an oil with a similar hydrophobicity to VX should promote its extraction. All the formulations reduced significantly the amount of VX quantified on and into the skin compared to the control. Wiping the skin surface with a pad already allowed removing more than half of VX. FE-W was the less efficient (85% of VX removed). The other formulations (FE-PE, S-PE and S-W) resulted in more than 90% of the quantity of VX removed. The charge of particles was the most influential factor. The low pH of formulations containing silica favored electrostatic interactions of VX with particles explaining the better elimination from the skin surface. Formulations containing FE had basic pH, and weak interactions with VX did not improve the skin decontamination. However, these low interactions between VX and FE promote the transfer of VX into the oil droplets in the FE-PE.


Assuntos
Compostos de Alumínio/farmacologia , Substâncias para a Guerra Química/toxicidade , Descontaminação/métodos , Compostos de Magnésio/farmacologia , Compostos Organotiofosforados/toxicidade , Silicatos/farmacologia , Dióxido de Silício/farmacologia , Pele/efeitos dos fármacos , Animais , Emulsões , Técnicas In Vitro , Suínos
17.
Drug Dev Ind Pharm ; 42(5): 818-24, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-26355722

RESUMO

Coated packagings with thin films containing antimicrobial agents are an alternative technology to ensure the protection of products against microbial contaminations. Indeed, they allow lowering the antimicrobial concentration in the bulk of the product while meeting the safety requirements and the growing consumer demand for low preservative concentrations. Microencapsulation is a suitable way for controlling active agent release and providing a long-term activity. This work aims at combining both technical solutions with coatings containing antimicrobial microparticles for the achievement of long-term sustained release. Polyethylene surfaces were functionalized with microparticles of poly(methyl methacrylate) (PMMA) loaded with phenylethyl alcohol (PEA) as antimicrobial agent by the dip coating process using a polyurethane binder. The release of PEA into water from coated polyethylene surfaces and from PMMA microparticles was investigated to assess the sustained release and its mechanisms. Films with various thicknesses of 400-1000 µm containing antimicrobial microparticles demonstrated unusual long-term release longer than 3 months. The diffusion of the antimicrobial agent through PMMA was the rate limiting step of the sustained release. PEA release increased as the contact area of the protruding microparticles with the external medium increased and the thickness of the film decreased. Such antimicrobial agents encapsulated inside thin coatings are promising with regards to antimicrobial preservation of products along their full shelf-life.


Assuntos
Anti-Infecciosos/química , Preparações de Ação Retardada/química , Liberação Controlada de Fármacos , Composição de Medicamentos/métodos , Álcool Feniletílico/química , Polímeros/química , Polimetil Metacrilato/química , Poliuretanos/química
18.
Int J Pharm ; 496(2): 1034-46, 2015 Dec 30.
Artigo em Inglês | MEDLINE | ID: mdl-26602293

RESUMO

Block copolymer nanoparticles often referred to as "block copolymer micelles" have been assessed as carriers for skin delivery of hydrophobic drugs. Such carriers are based on organic biocompatible and biodegradable materials loaded with hydrophobic drugs: poly(lactide)-block-poly(ethylene glycol) copolymer (PLA-b-PEG) nanoparticles that have a solid hydrophobic core made of glassy poly(d,l-lactide), and poly(caprolactone)-block-poly(ethylene glycol) copolymer (PCL-b-PEG) nanoparticles having a liquid core of polycaprolactone. In vitro skin absorption of all-trans retinol showed a large accumulation of retinol in stratum corneum from both block copolymer nanoparticles, higher by a factor 20 than Polysorbate 80 surfactant micelles and by a factor 80 than oil solution. Additionally, skin absorption from PLA-b-PEG nanoparticles was higher by one order of magnitude than PCL-b-PEG, although their sizes (65nm) and external surface (water-swollen PEG layer) were identical as revealed by detailed structural characterizations. Fluorescence microscopy of histological skin sections provided a non-destructive picture of the storage of Nile Red inside stratum corneum, epidermis and dermis. Though particle cores had a different physical states (solid or liquid as measured by (1)H NMR), the ability of nanoparticles for solubilization of the drug assessed from their Hildebrand solubility parameters appeared the parameter of best relevance regarding skin absorption.


Assuntos
Sistemas de Liberação de Medicamentos , Nanopartículas/química , Poliésteres/química , Polietilenoglicóis/química , Pele/metabolismo , Animais , Feminino , Espectroscopia de Ressonância Magnética , Masculino , Micelas , Solubilidade , Suínos
19.
Int J Pharm ; 494(1): 152-66, 2015 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-26235922

RESUMO

Polymer microparticles used for drug encapsulation and delivery have various surface morphologies depending on the type of formulation ingredients and parameters of the manufacture process. This works aims at investigating the critical parameters governing the morphology of microparticles and to underline the influence of their surface state on the drug release. The classical fabrication process by the "emulsion-solvent evaporation" is addressed using poly(ɛ-caprolactone) as the polymer and methylene chloride as the volatile organic solvent. The typical surfactants poly(vinyl alcohol) and polysorbate 80 have been considered. Scanning electron microscopy observations showed the various surface morphologies mainly depending on the stirring rate, the viscosity of the oil phase and by the presence of inappropriate surfactants. Because of arrested coalescence during solvent evaporation, the evaporation of the organic solvent causing particles hardening is the most important parameter that controls the morphology. Indeed, slow evaporation allows partial coalescence of the soft particles swollen by the organic solvent, whereas the particles morphology is frozen rapidly upon fast evaporation, thus preventing damaged surface states. Moreover, an effective stabilizing system for the primary emulsion is also a determining factor to control the final morphology. The morphology of the particles has a definite influence on the drug delivery of cholecalciferol. The surface morphology should be taken into consideration in the design of polymer microparticles because it allows a control over the drug release kinetics.


Assuntos
Emulsões/química , Preparações Farmacêuticas/química , Poliésteres/química , Química Farmacêutica/métodos , Composição de Medicamentos/métodos , Sistemas de Liberação de Medicamentos/métodos , Cloreto de Metileno/química , Microscopia Eletrônica de Varredura/métodos , Microesferas , Tamanho da Partícula , Polímeros/química , Solventes/química , Tensoativos/química , Viscosidade
20.
Eur J Dermatol ; 25(5): 424-35, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26109150

RESUMO

BACKGROUND: The stratum corneum (SC) is responsible for the barrier properties of the skin and the role of intercorneocyte skin lipids, particularly their structural organization, in controlling SC permeability is acknowledged. Upon contacting the skin, surfactants interact with the SC components leading to barrier damage. OBJECTIVE: To improve knowledge of the effect of several classes of surfactant on skin barrier function at three different levels. METHODS: The influence of treatments of human skin explants with six non-ionic and four ionic surfactant solutions on the physicochemical properties of skin was investigated. Skin surface wettability and polarity were assessed through contact angle measurements. Infrared spectroscopy allowed monitoring the SC lipid organization. The lipid extraction potency of surfactants was evaluated thanks to HPLC-ELSD assays. RESULTS: One anionic and one cationic surfactant increased the skin polarity by removing the sebaceous and epidermal lipids and by disturbing the organization of the lipid matrix. Another cationic surfactant displayed a detergency effect without disturbing the skin barrier. Several non-ionic surfactants disturbed the lipid matrix organization and modified the skin wettability without any extraction of the skin lipids. Finally two non-ionic surfactants did not show any effect on the investigated parameters or on the skin barrier. CONCLUSIONS: The polarity, the organization of the lipid matrix and the lipid composition of the skin allowed describing finely how surfactants can interact with the skin and disturb the skin barrier function.


Assuntos
Permeabilidade/efeitos dos fármacos , Absorção Cutânea/efeitos dos fármacos , Pele/efeitos dos fármacos , Tensoativos/farmacocinética , Biópsia/métodos , Humanos , Amostragem , Sensibilidade e Especificidade , Tensoativos/farmacologia , Técnicas de Cultura de Tecidos
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