RESUMO
On/into/through the skin drug delivery represents an attractive alternative for the oral route, providing local and/or systemic drug delivery. Due to its complex and well-organised structure, most of the drugs show difficulties to penetrate the human skin. Therefore, enormous efforts have been invested to develop intelligent drug delivery systems overcoming the skin barrier with particular emphasis on increasing therapeutic activity and minimizing undesirable side-effects. Most of these strategies require the use of singular materials with new properties. In particular, and on the basis of their inherent properties, including biocompatibility, biodegradability and relative low-cost, inorganic nanoparticles are ideal candidates for the development of skin drug delivery systems. This review provides an updated and comprehensive overview of the state of the art in the trends towards skin drug delivery with a particular focus in the attractive alternative offered by inorganic-based nanosystems.
Assuntos
Sistemas de Liberação de Medicamentos , Nanopartículas/uso terapêutico , Dermatopatias/tratamento farmacológico , Pele/metabolismo , Animais , Humanos , Nanopartículas Metálicas/química , Nanopartículas Metálicas/uso terapêutico , Minerais/química , Minerais/metabolismo , Minerais/uso terapêutico , Nanopartículas/química , Nanopartículas/metabolismo , Pontos Quânticos/química , Pontos Quânticos/metabolismo , Pontos Quânticos/uso terapêuticoRESUMO
Equilibrium and thermodynamic aspects of the adsorption of isoniazid (INH) onto halloysite nanotubes (HLNTs) and characteristics of the resultant drug/nanocarrier systems are investigated. Equilibrium studies were performed in aqueous medium at different times, temperatures and drug concentrations. The overall adsorption process was explained as the result of two simple processes: adsorption on the activated sites of HLNTs and precipitation of INH on HLNTs surface. Formation of the INH-loaded HLNTs was spontaneous, endothermic and endoentropic, increasing the thermodynamic stability of the system (ΔH=70.40kJ/mol; ΔS=0.2519kJ/molK). Solid state characterization corroborated the effective interaction between the components that was also described by modeling at molecular level by quantum mechanics calculations along with empirical interatomic potentials. Transmission electron microphotographs confirmed the double allocation and homogeneous distribution of INH in the nanohybrids. FTIR spectra revealed the interaction via hydrogen bonds between the inner hydroxyl groups of HLNTs and N in INH molecules. Loading of INH in the nanohybrids was approximately 20% w/w. Effective loading of INH and activation energies of the interactions enable to propose the designed nanohybrids in the development of modified drug delivery systems.
Assuntos
Silicatos de Alumínio/química , Antituberculosos/química , Portadores de Fármacos , Isoniazida/química , Nanotubos/química , Adsorção , Argila , Ligação de Hidrogênio , Concentração de Íons de Hidrogênio , Cinética , Modelos Químicos , Temperatura , TermodinâmicaRESUMO
This paper investigates desorption of 5-aminosalicilyc acid (5-ASA) adsorbed onto halloysite (HL). Desorption isotherms were fitted according to kinetic laws obtained considering release of 5-ASA from HL as the phase of desorption of the previously adsorbed drug molecules both inside the nanotubes of HL as onto the surface of clay particles and/or in the inter-particle spaces of their aggregates. Desorption isotherms has been also fitted with other equations frequently used in drug release kinetics studies. The best fitting corresponded to the kinetic model proposed; in agreement with the results of adsorption.
