Lactose granules

In a similar study of the factors influencing fhe flow of lactose granules, a strong negative correlation was found between the flow rate of granules and proportion of particles less than 150 pm (100 mesh) in size. ... 

The effects of storage after drying also may be assessed from the equilibrium moisture content curves. Storage conditions are not critical for the lactose granulation.f If the antacid formulation is stored at a relative humidity of only 65% it would, given sufficient time, absorb moisture until the content was 91%. This could be associated with poor flow characteristics and its attendant difficulties during compression. 

Impeller tip speed corresponds to the shear rate and has been used as a scale-up parameter in fluid mixing. For processing of lactose granulations in Gral mixers, however, it was shown by Horsthuis et al. that the same tip speed did not result in the same endpoint [in terms of particle size distribution (PSD)]. These findings were contradicted by other studies with Fielder mixers indicating that for a constant tip speed, successful scale-up is possible when liquid volume is proportional to the batch size and wet massing time is related to the ratio of impeller speeds. ° ... 

Zuurman K, Riepma KA, Bolhuis GK, et al. The relationship between bulk density and compactibility of lactose granulations. Int ] Pharm 1994 102 1-9. 

Nelson et al. (116) performed a study using sulfathiazole and lactose granules. They studied the effect of upper punch force and a difference between the upper and lower punch forces R values) on the EF. Upon adding lubricant to a formulation, the upper punch force was lowered from 1390 to 1010 kg and the difference between the upper and lower punch forces was reduced significantly from 630 to 30 kg, and they... 

FIGURE 14.2 Breakage of lactose granules under static compression. Adapted from Ref. [18] with permission. Copyright 2013, Elsevier. 

To facilitate model verification, experiments have been performed under similar conditions. The milling equipment (Thomas Wiley Mill, Thomas Scientific, Swedesboro, NJ) used in this study is a variable speed, digitally controlled, direct drive mill that provides continuous variation of cutting speeds from 600 to lldOipm with constant torque maintained throughout the speed range. Parametric studies were conducted with lactose granules to study the effect of impeller wall tolerance and feed rate on particle size reduction. 

Wikberg M, Alderborn G. Compression characteristics of granule materials. VII. The effect of intragranular binder distribution on the compactibilty of some lactose granulations. Pharm Res 1993 10(l) 88-94. 

Figure 4 Sieve analysis of lactose granules formed by massing and force screening showing effect of binder fluid level circles, 15.3% v/v squares, 18.4% v/v upward triangles, 23% v/v and downward triangles, 30.6% v/v. (From Ref. 6.)...

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