Tablet evaluation powder compression

In one study, the formulation efficiency of several direct compression materials was evaluated using instrumented press methodology.It was found that subtle changes in the structure of the component particles could lead to the observation of significantly different behaviors upon compression. The tablet hardness and compressibility of differently sourced sucrose materials, obtained at comparable compressional forces, was found to vary significantly with the source of the compound. To quantitative the results, an elastic recovery index was defined, and it was found that the indices of direct compressible materials were lower than those of poorly compressible powders. 

Schmidt PC, Rubensdorfer CJW. Evaluation of Ludipress as a multipurpose excipient for direct compression. Part I powder characteristics and tableting properties. Drug Dev Ind Pharm 1994 20 2899-2925. 

Chitin was evaluated as a direct-compression vehicle using powder flow properties and the physicomechanical properties of the manufactured tablets, and it was proven that this natural polymer has suitable characteristics for being used for this end. 

Moisute acts as a plasticizer and influences the mechanical properties of powdered materials for tablet compression. In the case of microcrystalline cellulose, at moisture levels above 5% the material exhibits significant changes consistent with a transition from the glassy state to the rubbery state [17]. The possible influence of moisture on the compaction behavior of powders was also analyzed by Gupta et al. [18]. This work evaluates the effect of variation in the ambient moisture on the compaction behavior of microcrystalline cellulose powder. 

Aly, S.AS. A new approach for evaluating the compressional behaviour of pharmaceutical powders II. Surface area of formulation excipients in a tablet system containing a non-compressible component. STP Pharma Sci. 1994, 4, 414-420. 

Nystrom, C. KarehiU, P.G. Studies on direct compression of tablets XVI. The use of surface area measurements for the evaluation of bonding surface area in compressed powders. Powder Technol. 1986, 47, 201-209. 

With regard to compressibility and compactibility, the considerations pertaining to raw materials in effervescent products are similar to the ones that prevail in evaluating raw materials intended for conventional tablets. However, poor compactibility cannot usually be compensated for by the use of binders, as this will prevent a rapid dissolution of the effervescent tablet. Addition of a binder is generally not as critical for the dissolution of effervescent granules or powders. 

Pesonen, T. Paronen, P. Puurunen, T. Evaluation of a novel cellulose powder as a filler-binder for direct compression of tablets. Pharm. Weekbl. Sci. Ed., 1989,11, 13-19. 

Compressed solids, tablets, or caplets, are prepared by placing the blend of component additives in a cylinder or die, above a moveable piston or punch. An upper punch is brought into the top of the piston, and pressure applied to the distal ends of the punches forces the powder into a compact (Fig. 7). The quality of the product depends upon the cohesive forces acting on the powder upon compression. These cohesive forces are influenced by the selection of additives in the dosage formulation. One method of evaluating... 

A further study was conducted to study the effect of compression temperature on the consolidation mechanism of the polymorphs of chlorpropamide [51]. The effect of environmental temperature on the compression mechanism of the A and C forms of chlorpropamide was investigated with an eccentric type tableting machine with two load cells and a noncontact displacement transducer. The temperature of the sample powders was controlled at 0 and 45°C, and these were compressed at almost 230 MPa. The tableting dynamics were evaluated by Cooper and modified Heckel analyses. The results suggest that particle... 

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