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.
Evaluative procedures for filmforming materials used in pharmaceutical applications.
The current interest in films for use in many pharmaceutical applications has motivated a study in which meaningful testing procedures have been developed or adapted for evaluating such films. The testing procedures studied were found to be rapid, efficient, reproducible, and valid for the evaluation of the pertinent properties of several different series of film-forming materials. The studies were conducted on the free films which were cast from these materials. Data gathered on solubility, moisture absorption, water vapor transmission rates, and the effects of temperature, humidity, and light on the free films indicate that the testing methods may be used to predict the effects of these variables on the performance of the films when they are utilized in a dosage form.
Effects of the mineral phase and valence of vanadium on vanadium extraction from stone coal
The influence of roasting on the leaching rate and valence of vanadium was evaluated during vanadium extraction from stone coal. Vanadium in stone coal is hard to be leached and the leaching rate is less than 10% when the raw ore is leached by 4 mol/L H2SO4 at 90°C for 2 h. After the sample is roasted at 900°C for 2 h, the leaching rate of vanadium reaches the maximum, and more than 70% of vanadium can be leached. The crystal of vanadium-bearing mica minerals decomposes and the content of V(V) increases with the rise of roasting temperature from 600 to 900°C, therefore the leaching rate of vanadium increases significantly with the decomposition of the mica minerals. Some new phases, anorthite for example, form when the roasting temperature reaches 1000°C. A part of vanadium may be enwrapped in the sintered materials and newly formed phases, which may impede the oxidation of low valent vanadium and make the leaching rate of vanadium drop dramatically. The leaching rate of vanadium is not only determined by the valence state of vanadium but also controlled by the decomposition of vanadium-bearing minerals and the existence state of vanadium to a large extent.