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Tableting. MCC–DCP formulation. Tablets were compressed and characterized for weight, thickness, and hardness. The mean weight values and corresponding relative
standard deviations (RSDs) are listed in Table VI. Weight variation was below the desired RSD of 2.0% for all the conventional
mill types. The two Gran-U-Lizer runs had slightly higher RSDs, but they were still below the 6.0% RSD allowed by US Pharmacopeia
criteria.
The tabletability profile (see Figure 7) shows that the tensile strength of all the tablet lots easily exceeded the desirable
target crushing strength of 2.0 MPa. Also, the compactibility profile (see Figure 8) shows that the tablets achieved a tensile
strength of 2.0 MPa at a solid fraction of approximately 0.80–0.81, indicating that strong bonds were formed at relatively
low solid fractions. All formulations performed well, regardless of the mill type used or difference in particle-size distribution.
MCC–lactose formulation. Weight variation for all the mill types was well below an RSD of 2.0%, and weight control is not considered a problem, regardless
of the difference in particle-size distribution. Weight, thickness, and hardness values are listed in Table VII.
Figure 9: Tabletability profile for microcrystalline cellulose–lactose formulation. (AUTHORS)
The tabletability plot (see Figure 9) shows that the tensile strength of all the lots easily exceeded the desirable target
of 2.0 MPa. However, the Gerteis milled formulation performed the best of all the lots. Its maximum tablet-crushing strength
was ~0.5 MPa higher than the other mill types. The compactibility profile (see Figure 10) shows that the tablets achieved
a tensile strength of 2.0 MPa when compaction was at a solid fraction of approximately 0.86–0.88. All formulations performed
similarly, regardless of the mill type used and the difference in particle-size distribution, except for the Gerteis milled
granulation.
Conclusions
Figure 10: Compactibility profile for microcrystalline cellulose–lactose formulation. (AUTHORS)
In general, the mill type used and resulting granulation particle-size distribution did not greatly influence the tabletability
or compactibility of either placebo formulation. The MCC–DCP formulation demonstrated excellent tableting and compaction properties,
regardless of the mill type used. Although a higher RSD for the tablet weight values using the Gran-U-Lizer was observed,
it is considered acceptable. Adjustments to the Gran-U-Lizer parameters might make the particle-size distribution slightly
lower and improve the granulation, tableting, and compaction performance.
Thomas A. Vendola is a scientist in solids development, and Bruno C. Hancock is a research fellow in material sciences at Pfizer, Eastern Point Rd., Groton, CT 06340, tel. 860.441.4430, fax 860.441.3972.
Articles by Thomas A. Vendola
