RESUMO
Nanostructured lipid carriers (NLC) are new drug systems composed of physiological lipid materials. The possibility of including different types of lipids into the NLC structure revealed the wide prospects for using biologically active natural oils for the development of the cutaneous preparations. In this study the formulation parameters of NLC on the basis of Siberian pine seed oil were evaluated including concentration of lipids, types of surfactants and storage conditions (4 degrees C, 20 degrees C, 40 degrees C). Size distribution and storage stability of formulations produced by hot high pressure homogenisation were investigated by laser diffractometry and photon correlation spectroscopy. The NLC were characterised by their melting behaviour using differential scanning calorimetry. The obtained data indicated the high physical stability of the developed NLC formulations.
Assuntos
Portadores de Fármacos/química , Lipídeos/química , Nanopartículas/química , Pinus/química , Óleos de Plantas/química , Varredura Diferencial de Calorimetria , Química Farmacêutica , Estabilidade de Medicamentos , Armazenamento de Medicamentos , Ácidos Graxos/química , Tamanho da Partícula , Poloxâmero , TensoativosRESUMO
We report on the first quantitative determination of the electric quadrupolar contribution to the nuclear spin-lattice relaxation in a transition metal. For 186Ir and 189Ir in Fe we have determined the magnetic and the electric quadrupolar part of the relaxation for magnetic fields between 0.01 and 2 T. The quadrupolar part gives information on the role of the orbital motion of the electrons for the relaxation process. Our results prove that the unexpected high relaxation rates in Fe and their magnetic field dependence are due to a nonorbital relaxation mechanism.
