Assuntos
Antivirais/administração & dosagem , Encéfalo/metabolismo , Sistemas de Liberação de Medicamentos , Zidovudina/administração & dosagem , Animais , Antivirais/sangue , Antivirais/farmacocinética , Barreira Hematoencefálica , Relação Dose-Resposta a Droga , Masculino , Ratos , Ratos Sprague-Dawley , Zidovudina/sangue , Zidovudina/farmacocinéticaRESUMO
Because many practitioners believe that the on-eye drying of contact lenses is a source of patient discomfort, we examined the relative dehydration rates of a variety of hydrogel contact lenses. Lens dehydration rates were determined by thermogravimetric analysis at 35[degrees]C. Using the FDA classification scheme for hydrogel lenses, we found that dehydration rates were as follows: group 4 greater than group 2 greater than group 3 greater than group 1. Within groups there was considerable variability in the rates at which lenses dehydrated. For lenses of the same type, we found a near-linear relationship between increasing lens power (which is closely related to center thickness) and decreasing rates of dehydration.
Assuntos
Lentes de Contato Hidrofílicas , Dessecação , Equipamentos Descartáveis , Óptica e Fotônica , Polímeros , Reprodutibilidade dos Testes , Temperatura , Termogravimetria , Fatores de TempoRESUMO
Two methods are described for the analysis of chlorhexidine sorption in soft contact lenses. The first is an isocratic ion-pairing high-performance liquid chromatographic (HPLC) method with UV detection at 220 nm that allows the determination of chlorhexidine, p-chloroaniline, and other chlorhexidine degradation products in ophthalmic solutions. This procedure had a detection limit of 0.1 ng. The second involves the catalytic oxidation of the lens matrix containing [14C]chlorhexidine to [14C]carbon dioxide and water. The label is then trapped as carbon dioxide in a cocktail and is analyzed by liquid scintillation counting. These methods are sensitive, accurate, and reproducible, and can be used independently or in conjunction for the determination of chlorhexidine sorption in soft contact lenses.
Assuntos
Clorexidina/análise , Lentes de Contato Hidrofílicas , Adsorção , Catálise , Fenômenos Químicos , Química , Cromatografia Líquida de Alta Pressão , Indicadores e Reagentes , Cinética , Oxirredução , ÁguaAssuntos
Dimetilditiocarbamato/metabolismo , Fungicidas Industriais/metabolismo , Tiocarbamatos/metabolismo , Ar/análise , Animais , Bile/metabolismo , Cromatografia em Camada Fina , Dimetilditiocarbamato/sangue , Feminino , Compostos Férricos/sangue , Compostos Férricos/metabolismo , Fungicidas Industriais/sangue , Glucuronidase/metabolismo , Absorção Intestinal , Lactação , Masculino , Troca Materno-Fetal , Leite/metabolismo , Gravidez , Ratos , Radioisótopos de Enxofre , Fatores de TempoRESUMO
Studies were made of a well functioning geometric total knee prosthesis, removed at autopsy from a sixty-one-year-old man, which had been used for eight months. The components were firmly embedded in bone with no evidence of loosening. There was significant deformation of the polyethylene tibial component, but no significant wear on the metallic component. Thin layers of fibrous tissue were found in some areas of the bone-cement interfaces.
