(26a) Characterization of Starch Products in Continuous Direct Compression Process

Direct compression (DC) is a highly desirable technique to manufacture tablets, and raw material attributes directly influence its effectiveness. Therefore, the selection of specific grades of excipients to achieve desirable powder flow and compression properties is of importance. As industry increasingly shifts toward continuous direct compression, this requires enhanced performance, reliable quality, and consistency directly from the starting ingredients. Powder feeding, as an initial and critical component of the continuous processing, affects the uniformity and quality of the final product and the reliability of the manufacturing system.

In this study, powder property measurements, including Shear Cell Response, Compressibility, Permeability, Dynamic Flow Energy, Bulk and Tapped Density, and Particle Size have been used to fully characterize starch ingredients (i.e., native maize starch, Starch 1500^®, Partially Pregelatinized Maize Starch and StarTab^®, Directly Compressible Starch (Colorcon, US). In addition, feeder characterization and refill studies were performed to compare the ability of feeders to perform consistent and accurate feeding of the starch ingredients. Principal Component Analysis (PCA) was then applied to examine the performance of the analyzed starch ingredients relative to other common excipients previously analyzed.

Results showed that compared with the other starch materials, StarTab has the largest particle size, most spherical shape, lowest Hausner ratio, lowest cohesivity, lowest compressibility and the greatest permeability. Thus, it is suggested that StarTab provides the best flowability and packing efficiency compared to native maize starch and Starch 1500. In the PCA model, all three starches displayed higher density than other excipients. Furthermore, StarTab was located in a more free-flowing region than the other two starch ingredients and thus consistent with previous results.

Due to sufficient feeder self-control, all three starches have comparable feeding performance. Markedly in feeder refill study, StarTab showed considerable smaller the total deviation of material fed in excess of the set point.

In conclusion, there was an increasing trend in improved flow and feeder refill performance from native starch to Starch 1500 to StarTab products. Based on the results obtained, StarTab is considered as an excellent candidate for use in pharmaceutical continuous direct compression (PCDC).