Powder blend properties

Jerome et al. in the 1980s studied the effects of compactor adjustments on powder blend properties. His team s research showed that pressure applied by the movable roller is not a predominant factor. They found that the most important variable was the compactor feed screw in relation to the roll speed. They correlated improved tablet compression hardness to the feed screw speed in relation to the speed of the rolls.P ... 

Since most rigid PVC extrusion is from powder blends, and the extrusion process—especially twin-screw—is sensitive to powder blend properties of flow, compact density, and bulk density, the need to be aware of bulk density variations is most important. This awareness is especially necessary with the supplier s requirement to reduce the residual VCM content of PVC resin, which in turn can mean more severe drying cycles after a steam-stripping operation in the process. Consequently, the bulk density of PVC resin, and its particle size distribution, may be somewhat different now than previously—and the resin particle surface may be a little harder, or less absorptive to liquid additives. Many resins are much drier than before. In short, the dry-blend, powder flow, and bulk density differences of current PVC resins may require subtle changes in mixing procedures and extrusion conditions to maintain product quality (more on this later). Knowing this before the resin is blended and extruded can minimize a host of production problems. 

During the preformulation stage, the chemical and physical properties of the dmg moiety are studied exhaustively to ensure stabdity, safety, bioavadabdity, and therapeutic efficacy. Tablets are produced directly by compression of powder blends or granulations, which include a small percentage of fine, particle-sized powders. 

The ductility of GRT-polyethylene blends drastically decreases at ground rubber concentration in excess of 5%. The inclusion of hnely ground nitrile rubber from waste printing rollers into polyvinyl chloride (PVC) caused an increase in the impact properties of the thermoplastic matrix [76]. Addition of rubber powder that is physically modihed by ultrasonic treatment leads to PP-waste ethylene-propylene-diene monomer (EPDM) powder blends with improved morphology and mechanical properties [77]. 

Chemical structure, concentration, size and distribution of the rubber phase as well as adhesion to the matrix determine processing and final properties, specifically the impact strength. In the case of a powder blend, like PVC/rubber-systems, the characteristic powder data have also to be taken into account. 

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. 

For a two-level factorial design, only two excipients can be selected for each factor. However, for the filler-binder, a combination of brittle and plastic materials is preferred for optimum compaction properties. Therefore, different combinations such as lactose with MCC or mannitol with starch can count as a single factor. Experimental responses can be powder blend flowability, compactibility, blend uniformity, uniformity of dose unit, dissolution, disintegration, and stability under stressed storage conditions. The major advantage of using a DOE to screen prototype formulations is that it allows evaluation of all potential factors simultaneously, systematically, and efficiently. It helps the scientist understand the effect of each formulation factor on each response, as well as potential interaction between factors. It also helps the scientist identify the critical factors based on statistical analysis. DOE results can define a prototype formulation that will meet the predefined requirements for product performance stability and manufacturing. 

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... 

Lastly, manufacturability of a dmg product can be affected by the physical properties of the drug substance. Manufacturability refers to the ability to execute a process efficiently, without excessive operator intervention, and without the need for specialized equipment designed solely to overcome specific product properties. In the case of drug product manufacturing, this typically includes the ability to transfer powder blends through each drug product unit operation. The physical properties of the API such as particle size and shape can affect the flowability of the intermediate and final powder blends. 

In essence, the test battery should include XRPD to characterize crystallinity of excipients, moisture analysis to confirm crystallinity and hydration state of excipients, bulk density to ensure reproducibility in the blending process, and particle size distribution to ensure consistent mixing and compaction of powder blends. Often three-point PSD limits are needed for excipients. Also, morphic forms of excipients should be clearly specified and controlled as changes may impact powder flow and compactibility of blends. XRPD, DSC, SEM, and FTIR spectroscopy techniques may often be applied to characterize and control polymorphic and hydrate composition critical to the function of the excipients. Additionally, moisture sorption studies, Raman mapping, surface area analysis, particle size analysis, and KF analysis may show whether excipients possess the desired polymorphic state and whether significant amounts of amorphous components are present. Together, these studies will ensure lotto-lot consistency in the physical properties that assure flow, compaction, minimal segregation, and compunction ability of excipients used in low-dose formulations. 

M. koenigii (Linn), commonly known as the curry leaf plant, is highly valued for its characteristic aroma and medicinal properties. Its leaves are used extensively for culinary purposes, especially in curries and chut-neys, but also in vegetable, fish and meat dishes, pickles, buttermilk preparations, curry powder blends, etc. The major volatile components in curry leaf are a-pinene, 3-caryophyllene, (Ii)-P-ocimene, linalool and P-phellandrene. M. koenigii is a rich source of carbazole alkaloids. Its leaves, roots and bark are a tonic, stomachic and carminative. It is shown to possess a hypo-cholesterol effect and many other health benefits. The crop promises great scope in various biochemical and industrial applications in the future. 

During product manufacture large volumes of powder blends are fed through production equipment/processes, and it is essential to be able to accurately determine, define, and control powder properties to ensure reproducible manufacture and product performance. Therefore the characterization of the physicochemical properties of powder blends is extremely important. It is well accepted that there are inherent difficulties in characterizing the entire mass of a bulk powder blend or process stream, so it is essential to remove and analyze discrete samples. 

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