Powder blending measurement

The 10% w/w APAP powder blend was roller compacted. Different moisture contents were achieved by equilibrating and roller compacting the above powder blend under 24, 45, and 65% RH conditions, representing 3.3, 5.0, and 6.3% w/w moisture content, respectively. Compacts were prepared at 5.0, 6.0, and 7.2 rpm roll speeds with the powder feed rate and roll pressure kept constant. Compaction run time was four minutes at each roll speed. Samples were also collected for off-line measurements of... 

The angle of repose of a powder blend, effective angle of internal friction (EAIF) from shear cell measurements, and the mean time to avalanche (MTA) in powder cohesivity tests are useful for assessing the flow of a tableting mixture at various scales (15 18). 

In a setup-dominant process, it is important that the development function understand where the setup must be centered (targeted). This information is most useful when instruments can effectively and accurately measure the property of the intermediate material (e.g., powder blend) or dosage unit. This capability is reinforced whenever an instrument reading outside the given specifications causes an equipment response (e.g., activation of a servo motor on a tablet press). Caution limits within the normal product limits are established purposefully to effect this kind of control. 

The Jenike shear cell tester is classified as a direct shear tester that is capable of providing information on a solids cohesive strength as well as its wall friction properties. The tester allows us to measure the strength of a powder blend as a function of pressure applied to it. These are two main considerations when design a bin or hopper to ensure reliable material flow. The tester consists of a base, a moveable shear ring resting on top of the base, and a top cover lid (Fig. 7.3).61 The base is fixed while the lid rotates at a constant low rate. Powder blend is placed in the ring and base and a... 

Ufret, C. Morris, K. Modeling of powder blending using 78. on-line near-infrared measurements. Drug Dev. Ind. 

Pharmaceuticals On-line measurement of moisture and particle size in the fluidized-bed processing with NIR spectroscopy 13 Automated system for the on-line monitoring of powder blending processes using NIR spectroscopy 14... 

Thus, to advance beyond the current state of the art, we need to improve experimental techniques for measuring powder flow and powder constitutive behavior. Important efforts, mentioned earlier in this chapter, are under way using a variety of noninvasive technologies, but much remains to be done before powder blending processes can be designed and scaled-up reliably. The reader is advised to stay tuned, as the field is likely to evolve rapidly in coming years. 

All interactive mixtures were measured in triplicate and results were given as mean of three standard deviation. A paired t-test was performed for the results gained by Monckedieck et al. [11] to check for significance between the FPFs of the powder blends (GraphPad Prism, Version 6, Graph Pad Software Inc., La JoUa, USA). 

The PVC blend was prepared and investigated in two concentrations, 209 and Al%. Its composition corresponded in principle to a commercially available (though not commercially successful) blend, although an average concentration of 35% was planned for the industrial applications. For comparison purposes pure PAni powder was measured (as a molding made at room temperature and 10 kbar). The thermopower and conductivity and their temperature dependence were measured using standard techniques [78,80J. Conductivity as a function of temperature is shown in Fig. 19.61. 

Superabsorbents. Water-sweUable polymers are used extensively in consumer articles and for industrial appUcations. Most of these polymers are cross-linked acryUc copolymers of metal salts of acryUc acid and acrylamide or other monomers such as 2-acrylamido-2-methylpropanesulfonic acid. These hydrogel forming systems can have high gel strength as measured by the shear modulus (134). Sometimes inorganic water-insoluble powder is blended with the polymer to increase gel strength (135). Patents describe processes for making cross-linked polyurethane foams which contain superabsorbent polymers (136,137). 

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