Tablet immediate-release compressed

That tablets can be formulated to uniquely meet these criteria accounts for their emergence as the most prevalent oral solid dosage form. Although several different types of tablets may be distinguished, they are mostly made by compression, intended to be swallowed whole and designed for immediate release. This paper presents a systematic approach to the design and formulation of immediate-release compressed tablets. 

The testing procedures used in this work have all been well described in the literature (4) and are focused on understanding the compression behavior of the powder samples and the mechanical properties of the resulting compacts. These methods are summarized in Table 1. For brevity, we have limited our initial studies to single component systems, but recognize that more work is needed in the future to understand the complex behavior of multicomponent mixtures. The current work should provide a sound basis for further work on such systems. It is intended that this treatise will enable pharmaceutical formulation scientists to better understand the similarities and differences between the most common grades and types of excipients, and will facilitate the rational selection of excipients for use in the development of immediate release tablet formulations. 

Intuitively, SF is a measure of the degree of compression because it increases with applied pressure. Mechanical properties of powder compacts are dependent on SF and best compared at the same SF. The authors laboratory selected 0.85 SF as its standard because it approximates the midpoint of the range typical of immediate release tablets (0.8-0.9). 

A powder compact s TS is the stress required to separate its constituent particles in tensile mode. This is measured for the tableting indices by transverse compression of the square compacts, using narrow platens. Stresses build within the sample until it fails in a tensile mode that is perpendicular to the direction of platen movement. Tablets that are manufactured on a traditional tablet press and that have high TS are considered hard and generally robust, and so this is a highly desired attribute for immediate release and other tablet types. 

Apart from immediate release tablet formulations, neural networks have also been applied to modeling immediate release capsule formulations and rapidly disintegrating or dissolving tablets. In the latter, Sunada and Bi from Japan used both statistics and neural networks to optimize both the formulation and processing conditions for rapidly disintegrating tablets developed using both direct compression and wet granulation techniques. 

Owing to the hydrophilic nature of chitosan, this compound has been used directly as compressible diluent in tablets. Chitosan has excellent properties as excipient for direct compression of tablets, where the addition of 50% chitosan results in rapid disintegration. The DD determines the extent of moisture absorption. Also, in immediate-release formulations, e.g., as a disintegrant in small amounts, where it has been found to have effects similar to or better than those of microcrystalline cellulose. Chitosan at concentrations higher than 5% is a better disintegrate than corn starch and microcrystalline cellulose, depending on chitosan crystallinity, DD, MW and particle size [61]. In addition, it has excellent tablet binder properties compared to other excipients [62]. 

EC is an inert, hydrophobic polymer that has been studied substantially for its application as a matrix-forming material in direct compression tablets. Direct compression is the preferred method of manufacture for producing tablets intended for immediate or sustained release. There have been reports on the compressibility and compatibility of EC [307-310] and on its use as a matrix-forming material in direct compression tablets for the delivery of soluble and poorly soluble drugs [311-316]. Tablet hardness [310,314,315], the particle size of the polymer [314,315,317], and the viscosity grade [313,314] were observed to directly affect the drug release rate. It was noted that tablet hardness affected the... 

A coating can be applied by compression using specially designed tablet presses. The same process can be used to produce layered tablets which can comprise two or even three layers if complete separation of the ingredients is required. This process is used when physical separation of ingredients is desired due to incompatibility or to produce a repeat-action product. The formulation can also be designed to provide an immediate and a slow-release component. Release rates can be controlled by modification of the geometry, the composition of the core, and the inclusion of a membrane layer. 

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