Powder compression

The ability of chitosan hydrochloride to enhance the transcorneal permeability of the drug has been demonstrated [289]. Polyethylene oxide (PEO) was used as a base material to which ofloxacin-containing chitosan microspheres prepared by spray-drying were added and powder compressed resulting in circular inserts (6 mm). 

Squib. 1) (General). Any of various small size pyrotechnic or explosive devices 2) (Specific). A small explosive device similar in appearance to a detonator, but loaded with low explosive, so that its output is primarily heat (flash). Usually electrically initiated, and provided to initiate action of burning type munitions, pyrotechnic devices and rocket propellants. An electrical squib consists essentially of a tube containing a flammable material, and a small charge of powder compressed around a fine resistance wire connected to electrical leads or terminals (Ref 40a, p 135)... 

Explosion, Effects of the Physicol Structure and the State of Aggregation on the Detonating Capacity of Explosives. Liquid TNT detonates only if the diam of the specimen is above 32mm. TNT powder compressed to the sp gr of the liquid TNTj detonates at diams of 2.1mm or greater. Pieces of solid TNT are similar to liquid TNT- Maximum diams for liquid TNT and TNT powder are 2.3 and less than 2mm, respectively. Gas space between expl particles facilitates deton, presumably because hot gases spread the deton Ref A.Ya. Apin V.K. Bobolev, ZhFizKhim 20, 1367—70(1946) Engl abstract in CA 41, 3297(1947)... 

Heda PK, Muller FX, Augsburger LL. Capsule filling machine simulation. I. Low-force powder compression physics relevant to plug formation. Pharm Dev Tech 1999 4(2) 209-219. 

Black powder, compressed or Gunpowder, compressed or Black powder, in pellets or Gunpowder, in pellets 0028... 

L. E. Morris and J. B. Schwartz. Isolation and densification regions during powder compression. Drug Dev. Ind. Pharm. 12(4) 427-A46. 1995. 

Powder compressibility parameter k [M I,T- = AWCAp-V,) (where AV and Ap are the changes in tablet volume V and applied pressure p, respectively, and Vf is the final tablet volume)... 

For the purpose of this study, the average powder compressibility parameter K was calculated as shown in Table 6. 

Hausner Ratio and Powder Compressibility. The ratio between the loose and packed bulk density, Pbdl and Pbdp respectively is known as the Hausner Ratio (HR) and is used as an indication of the cohesiveness of the materials, see Ref. 20. In addition to the HR, the powder compressibility is also used to define cohesiveness. This is expressed as 100(/9bdp — Pbdl)/Pbdp-... 

A tableting process depends on the physical parameters, as e.g. mean particle diameter dp, bulk density (porosity), flow behaviour (lubricating ability) of the powder, which depends also on humidity. These physical properties can be replaced by the lumped parameter powder compressibility K [136],... 

Pressure methods Unidirectional compaction 1. Powders compressed within die cavity into cylindrical or other simple shapes by action of punch. Tableting, powder pressing, dry pressing, hot pressing Tablet machines, powder presses. 

Powders compressed into flat-faced tablets by action of punch and die, comminuted and screened to form feed for final compression. Dry granulation, slugging, pre-compression Heavy duty tableting press... 

Ultrasound-assisted powder compression has been widely employed in metallurgy as well as in the plastic and ceramic industries [84], The first references in the pharmaceutical industry are two patents in 1993 [85] and 1994 [86], Since then, some papers have presented experimental data in this field [45,87-92],... 

The manufacturing process of tablets principally consists of three stages filling the die with the powder, compressing the powder, and ejecting the tablet from the die. 

Despite this critique of the Heckel equation, the analysis of Heckel plots has been intensively used for the description of powder compression [128, 133-136], Gabaude et al. [136] stated that the analysis is quite useful when defining preconditions exactly and apply correct displacement measurement. 

Kawakita, K., and Ltidde, K. H. (1970/71), Some considerations on powder compression equations, Powder Tech., 4, 61-68. 

In addition to the Heckel approach, other techniques may be applied to the characterization of powder compression. One of these approaches was proposed by Cooper and Eaton [12] ... 

Duberg, M., and Nystrom, C. (1986), Studies on direct compression of tablets. 17. Porosity pressure curves for the characterization of volume reduction—Mechanisms in powder compression, Powder Technol., 46, 67-75. 

SYNS BLACK POWDER, compressed (DOT) BLACK POWDER, granular or as a meal (UN 0027) (DOT) BLACK... 

When compressible and non-compressible excipients are mixed together, the adsorption of the non-compressible excipients onto the surface of the compressible excipients will reduce mixed powder compressibility. Lerk et al. and te Wierik et al. studied a new generation of starch products, which have a high surface area as excipients in pharmaceutical tablets, and confirmed that there is a positive relationship between the specific surface area and the binding capacity (i.e., compactibility). The surface area that takes part in the interparticle attraction is small, and only a minor fraction of the... 

Rowlings, C.E. Wurster, D.E. Ramsey, P.J. Calorimetric analysis of powder compression II. The relationship between energy terms measured with a compression calorimeter and tableting behavior. Int. J. Pharm. 1995, 116, 191-200. 

The mechanical strength of a tablet plays an important role in the development and control procedures. Crushing strength is the most widely used test of mechanical strength. It is defined as the compression force that, when applied diametrically to a tablet, just fractures it. Tablet hardness depends on the weight of material and the space between the upper and lower punches at the moment of compression. Inconsistent hardness values are likely to result from variation in these parameters. The fundamentals of powder compression are given in a report by Leuenberger and Rohera. ... 

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