Gases are compressible fluid and has no definite shape. Properties of Gases: 1) A sample of gas assumes both the shape and volume of the container. 2) Gases are compressible. 3) The densities of gases are much smaller than those […]
Relative humidity: It is a ratio, expressed in percent, the amount of atmospheric moisture present relative to the amount that would be present if the air is saturated. Since the later amount is dependent on temperature. Relative humidity is a […]
SETTLING IN SUSPENSIONS : One aspect of physical stability in pharmaceutical suspensions is concerned with keeping the particles uniformly distributed throughout the dispersion. It possible to prevent settling completely over a prolonged period of time, it is necessary to consider the […]
Flow Property: (1) The flow properties of solids have great impact on the tableting processes since their manufacturing require the flow of powder from a storage container to tablet dies. (2) Weight and content uniformity are also dependent on flow […]
Micromeritics is the science and technology of small particles and includes the study of the fundamental and derived properties of individual as well as a collection of particles. The micromeritic properties of a drug can be related in a significant […]
Average particle size: Suppose that the particle size of a powder is analysed and the number of particles in each size range is determined, from the data, the average particle size of the powder may be calculated as Davg = […]
Optical Microscopy: Equivalent diameter: It is used to determine projected area diameter, Feret’s diameter and Martin’s diameter. Range of analysis: 1 μm to about 100 μm. Methodology: Firstly, the powdered substance is placed over the stage and obseved through the […]
Specific surface: The specific surface of a powder is defined as the surface area per unit volume (Sv) or per unit weight (Sw). SURFACE AREA DETERMINATION METHODS: The surface area can be determined directly by one of the following two […]
DERIVED PROPERTIES OF POWDERS: There are numerous derived properties that are based on fundamental properties. Those with particular relevance to pharmacy are discussed here. Packing geometry Porosity Density Bulkiness Flow property Packing Geometry: A set of particles can be filled […]