Influence of the Glidant on Diluent Flow Characterization Using Shear Cell Method.

Purpose: The aim of this study was to compare the bulk lactose flow behavior with a defined fraction with smaller particles obtained by sieving from the bulk lactose and to evaluate the effect of a glidant addition on both samples. These powders showed, in a previous work, similar flow indexes (ff_c) that motivated the addition of colloidal silicon dioxide in order to observe if there were any changes in their flow behaviors. Methods: To evaluate this effect on the diluent flow behavior, the methods described in the European Pharmacopeia were used. Results: The results obtained from conventional methods and shear cell methods (using the Powder Flow Tester) were compared, and they showed evident differences in the bulk and tapped densities values and flow classifications. The lactose monohydrate (F_Total) and lactose with particles smaller than 63 μm (F < 63) analyzed in a previous study presented similar ff_c. To these pure powders a glidant was added, in increasing proportion (0.25—1.00%). The results obtained for all powders with colloidal silicon dioxide showed an improvement in its flow behaviors in comparison with pure powders. Conclusion: All the parameters studied showed an evident effect of the glidant used. For the same amount of glidant, the F < 63 presented worse flow profiles than F_Total because its particles have a larger surface area. The F_Total + 0.25 flow profile was more similar to the F < 63 + 0.50 flow profile than F < 63 + 0.25 flow profile. For both powders, the maximum amount of glidant that produces effect was 1.00% for F < 63 and 0.75% for F_Total, respectively. In all powders, the occurrence of caking was not observed. [ABSTRACT FROM AUTHOR]