Tablet formulation blending

From 1982 through 1985, few NIR analyses of dosage forms were published. Since 1986, there have been many articles. The first was a 1986 paper by Ciurczak and Maldacker [33] using NIR for tablet formulation blends, examining the use of spectral subtraction, spectral reconstruction, and discriminant analysis. Blends were prepared where actives—aspirin (ASA), butalbital (BUT), and caffeine (CAF)—were omitted from the formulation or varied over a range from 90 to 110% of label strength. 

Fig. 12 Percent weight gain associated with the exposure of tablet formulations to 80% relative humidity at 40°C. Formulation A (0) was essentially a 1 11 blend of the drug entity and microcrystalline cellulose, while formulation B ( ) was essentially 1 5.5 5.5 drug-microcrystalline cellulose-starch.

In this section a study is described in which tablets prepared with binary blends of a filler-binder and a disintegrant are evaluated, with respect to their physical stability after storage under tropical conditions. With the results of this study a selection from the excipients can be made, which are suitable for use in tropical countries. Tablet formulations can be developed with the thus selected excipients. 

The rate of tlie compaction process is another variable that should be considered throughout development, including scale-up. Typically, the development of a tablet formulation takes place on tablet presses that are relatively slow. The tableting rate is important to consider for several reasons. Blend flow is important to ensure bulk blend transfer into the tablet press (hopper) and consistent die fiU. Variation or difficulty in the bulk flow and die fill can contribute to tablet weight variation. As the compaction rate increases, the blended material must be able to... 

When manufacturing a tablet formulation by direct compression, the particle size and size distribution of excipients have a significant impact on blending homogeneity, powder segregation, and flowability. This can result in unacceptable content uniformity and high tablet weight variation. In such situations, control of excipients can be critical to product quality. 

First, the die is filled when it passes beneath a stationary feed frame and the lower punch is in the filling position. Tablet weight variation is dependent on uniform powder filling into the die cavity. Since the residence time of the die under the feed frame is very short, the formulation blend must flow easily and reproducibly. 

Most drug and inactive excipients used in tablet formulation are in the solid state as amorphous powder or crystals of various morphological structures. There may be substantial differences in particle size, surface area, crystal morphology, wetting, and flowability as well as many physical properties of drug, excipients, and their blends [16]. Table 12 describes common micromeritic topics important to pharmaceutical preformulation. 

Forced degradation studies are carried out either in the solution state and/or in the solid state. Usually the forced degradation testing is carried out on one batch of drug substance and/or one formulation blend (capsules and tablets). This forced degradation testing should not be part of a formal stability program. 

A growing interest in direct compression formulas has developed, mainly for economic reasons. The number of processing steps has been reduced, and the availability of many direct compression materials allows for a simplified tablet formulation. Direct compression formulations require blending only therefore, lakes and other pigments are used because the elimination... 

When using alginic acid in tablet formulations, the alginic acid is best incorporated or blended using a dry granulation process. 

In tablet formulations, ethylcellulose may additionally be employed as a binder, the ethylcellulose being blended dry or wet-granulated with a solvent such as ethanol (95%). Ethylcellulose produces hard tablets with low friability, although they may demonstrate poor dissolution. 

Excipients are not only one of the major components and key factor governing the formulation performance of a tablet formulation, but also one of the key sources of variability in the formulations. Use of multiple excipients and a high proportion of excipients, as well as variations in particle size, and blending behavior, are considered... 

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