Characterization and evaluation of the performance of starch and cellulose as excipients for direct compression technique

Abstract

Purpose: To investigate the influence of two often-used excipients (starch and microcrystalline cellulose) on the physical properties of powder blends and tablets that contain mannitol as diluent.Methods: Powder and powder mixtures of three commonly used excipients (starch, mannitol and microcrystalline cellulose) were thoroughly examined using the angle of repose for flowability, particle size analyzer to determine the diameter of the particles, scanning electron microscopy (SEM) for morphological assessment, and x-ray diffraction to determine crystalline/amorphous characteristics. Tablets were prepared by direct compression technique and were evaluated for mechanical strength and disintegration behavior as part of quality control test.Results: The results showed that increase in MCC concentration of the mixture leads to significantly enhanced flowability (p < 0.05) when compared to starch. The angle of repose for mannitol/MCC powder mixture with 70 % w/w MCC was approximately 29°, indicating good flow properties of thepowder mix. Moreover, starch tablets containing MCC exhibited better mechanical strength and longer disintegration time, while, at 1:1 ratio of MCC and mannitol, tablet disintegration was faster (33.0 ± 5.2s)Conclusion: MCC (at 30 %w/w in the blend) produces optimal flow of the powder blend and superior mechanical strength, Keywords: Tablet disintegration, Flowability, Starch, Hardness, Mechanical strength