Sieve cut potency

Achieve a homogeneously distributed API within the range of granulation particle sizes Quality Granulation sieve cut potency Tablet content uniformity... 

A granulation optimization study on model Drug A targeted the least variability in sieve cut potency.35 The highest percentage bypass levels were concentrated in the region of minimal roll force values and maximal gap width values. 

The variability of sieve cut potencies for Drugs A and B as a function of various roll force levels and dry granulation equipment manufacturers is tabulated in Table 6.14. The change in equipment type had no significant affect on sieve cut potency variability for Drug B. The increased roll force using the same equipment type did impact the variability of sieve cut potencies for Drug A in terms of RSD. 

A fifth process challenge in the optimization of a dry granulation process is to achieve a granulation that is resistant to fluidization and sifting segregation forces. In general, process parameters that influence segregation potential are similar to those that influence variability in sieve cut potency. 

TABLE 6.14 Variability in Sieve Cut Potency as a Function of Roll Force... 

Since the properties that influence granulation blend uniformity (variability in sieve cut potency, segregation potential) have already been established during the dry granulation process, a minor secondary function of the final blending process... 

Therefore, for a given formulation (brittle vs ductile), a balance in the level of applied compaction force and roller gap width must be identified to control factors that influence tablet content uniformity (variability in sieve cut potency, sifting, and fluidization segregation) without sacrificing factors that influence manufacturability (compression force required to achieve target tablet hardness). 

One way to test an ordered mixture is to pass the blend through a nest of sieves and assay each particle size fraction. The lesser the variation in potency across the cuts, the better the ordered mix. Note that this test is highly dependent upon how much energy goes into the sieving process. Shaking the sieves by hand would be expected to produce different results than using an ultrasonic method. 

---