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Table IV: Physical and chemical results for blends. Blend uniformity and effusivity results.
Similarly, with the same 75:25 diluent ratio, MCC–DCP blends lubricated with MgSt-M exhibited 2–3 times more densification
than MgSt-D (Batch 7 versus Batch 11). Also MCC–LAC blends with a 75:25 ratio, when lubricated with MgSt-M, showed about 1.6
times more densification than blends with MgSt-D (Batch12 versus Batch 14). Moreover, within the MCC–LAC diluent system, the
50:50 diluent ratio tends to show higher delta effusivity than the 75:25 ratio. (Batch 12 versus Batch 16, and Batch 14 versus
Batch 17). This result could be attributed to the increasing contribution of lactose in the formulation, particle–particle
interaction, and diluent-type sensitivity to the influence of MgSt. Although the mechanism of the densification may not be
fully understood, it is believed that the finer particles of the lubricant tend to displace the air pockets between larger
particles and occupy the interstices with a resultant more densely packed powder mixture. Such particulate packing, presumably
a result of MgSt addition, could disturb the established blend uniformity.
Table V: Factors and responses—the influence of MgSt on type and concentration.
Content uniformity. The data in Table VI show the compression batches containing MCC–DCP and MCC–LAC binary diluents systems. Results show that
except for Batch 8, all batches gave acceptable results for content uniformity. The mean assay for 10 tablets for Batch 8
was 96.9%. The %RSD was 7.9, however, which is much higher than the acceptable limit (20). Batch 8 was lubricated with 1.0%
of MgSt-M for 10 min. This result implies that an extended period of lubrication could affect the tablets' content uniformity.
In their study, El Hagrasy, Chang, and Kiang alluded to the risk of lubricant mixing when they monitored the lubrication of
placebo granules with various levels of MgSt (22). Their findings suggested that improper mixing of lubricant in the final
blends could compromise tablet dissolution and quality.
Figure 9
Based on a Plackett–Burman design, % MgSt, MCC–DCP ratio, Avicel type, % APAP, and lubrication time were evaluated for their
influence on ejection force and total compression force. Using the method of least squares, regression models were developed
for the total force (precompression and main compression forces) and the ejection force to elucidate the influence of the
lubricants on the compression process.
