Tablet formulations direct compression

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... 

Direct compression is a simpler alternative tablet manufacturing method. With direct compression, tablets are compressed directly from a powder mixture of an API and appropriate excipients. Like granulation methods, this approach is also based on the required flow, compressibility, and compactibility of a formulation. Direct compression offers both time and economic advantages by eliminating intermediate granulating and drying steps. 

Saleh, S.I. Aboutaleb, A. Kassem, A.A. Stamm, A. A contribution to the formulation of effervescent tablets by direct compression. Labo-Pharma Probl. Tech. 1984, 32,163-166. 

Soft gelatin capsules are not an inexpensive dosage form, particularly when compared to direct compression tablets [3]. There is a more intimate contact between the shell and its liquid contents than exists with dry-filled hard gelatin capsules, which increases the possibility of interactions. For instance, chloral hydrate formulated with an oily vehicle exerts a proteolytic effect on the gelatin shell however, the effect is greatly reduced when the oily vehicle is replaced with polyethylene glycol [3]. 

Khan, K.A., and Rhodes, C.T., Effect of variation in compaction force on properties of six direct compression tablet formulations, J. Pharm. Sci., 65 1835-1837 (1976). 

In previous work, the formula used were optimized by direct compression [13]. The area under the dissolution curve was optimized and validated by a composite design. However, the formulation gave poor powder flow as well as variability in the dissolution parameters. Thus the double compression process was investigated in order to change the powder into solid aggregates and therefore to enhance homogeneity, density and powder flow in addition it was expected that this process would reduce the variability between tablets. 

With the exception of the formulation obtained by direct compression in a rotary machine, the dissolution profiles were well fitted by the Weibull function. A high density in the centre of the tablets may explain the sigmoid dissolution profiles. A percentage of the drug remains imprisoned in the matrix after the dissolution test. It is possible to suppose that, in the densified central zone of the tablet, the diameters of the pores are smaller than the diameters of the drug particles covered by the inert polymers. 

A significant difference was found between tablets for the formulations obtained by direct compression in a rotary machine and by separate compaction. 

In summary, when tested, the grades of calcium phosphate dibasic discussed above exhibited mechanical properties that were very appropriate for tablet compaction and thus for formulation processing by direct compression, dry granulation, or wet granulation. With this in mind, it is easy to understand the popularity of DCP in pharmaceutical tablet formulations. 

Sutton SC, LeCluyse EL, Engle K, Pipkin JD, Fix JA. Enhanced bioavailability of cefoxitin using palmitoylcarnitine, II. Use of directly compressed tablet formulations in the rat and dog. Pharm Res 1993 10 1516-1520. 

This particular formulation was a direct compression formula containing two active ingredients Active A, 60 mg, and Active B, 4 mg per tablet. The actives made... 

Formulations of Tablets Obtained by Direct Compression (Lab Scale)... 

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