A method for hermetically packing solid medicinal forms
Four basic methods are in existence for protecting solid drugs from external influences: i) coating of tablets with a film by pelleting or in a fluidized bed; 2) packaging preparations in polymeric film materials; 3) packaging in metal foil; 4) packaging in mixed films consisting of aluminum foil and cellophane, polypropylene, or other polymeric material. This method has the widest application at the present time. Methods have been developed not only for packaging in mixed films but also automatic lines of diverse productivity have been established.
EVALUATION OF POLYMERIC MATERIALS. I. SCREENING OF SELECTED POLYMERS AS FILM COATING AGENTS.
A procedure has been developed for the systematic evaluation of mechanical, thermal, and stability properties of polymeric materials through the study of unsupported films. Films of selected vinyl, acrylic, and cellulosic polymers were prepared by the knife edge applicator method and the mercury substrate technique. The mercury substrate technique afforded superior control of film thickness and facilitated film removal. Films that were very permeable to water vapor were rather impermeable to oxygen and vice versa. This relationship is discussed as it relates to a combination of the hydrophilic-lipophilic and pore theories of film structure. The unsupported vinyl films possessed superior mechanical properties of those tested. Moisture absorption by the polymer films was negligible. There was no discernible decomposition according to infrared analysis of the films, due to thermal, photo-oxidation, and/or aging effects.
Investigations of dielectric gratings using electrodynamic models based on volume integral equations
Eigenmodes of planar and cylindrical dielectric gratings (DGs) and electromagnetic wave scattering from multiplayer DGs are investigated. The DG characteristics are calculated using numerical-analytical solution of integral equations (IEs).