TO STUDY THE EFFECTS OF SOLVENT AND RELATIVE HUMIDITY ON RHEOLOGICAL AND THERMAL PROPERTIES OF MICROCRYSTALLINE CELLULOSE GRANULES USING HYDROXYPROPYL METHYLCELLULOSE AS BINDER

Solvent used for preparing binder solution in a wet granulation process is one of the major factors which dictate the granule properties. Aim of our current research was to understand the effect of solvents on flow properties of Microcrystalline Cellulose granules prepared using Hydroxypropyl Methylcellulose as a binder by using rheological tools and subsequently studying the effect of relative humidity on the rheology of dried granules. Granules were prepared by using 2.5% w/w binder solution in water and water: ethanol mixture (20:80 v/v). Prepared granules were dried, sieved, and further analyzed. Effect of relative humidity on the flowability of dried granules was studied at 22%, 52%, 75% RH at room temperature for 48 hours. Modulated Differential Scanning Calorimetry and Powder rheometer were used to study the thermal and flow properties of wet, dried, and humidity exposed granules. Results show that the hydro-alcoholic batches show greater resistance to flow in wet granule stage. But, its dried granules display good flow characteristics as evident from Basic flowability energy values. Bulk density of granules depends on the solvent used and in turn, affects the rheological properties of granules. Intragranular moisture levels are affected by solvent used on exposure to different humidity conditions. This work shows that solvent plays a major role on the rheology of microcrystalline cellulose granules which could help formulation scientist for the choice of better solvent for binder preparation and the optimum relative humidity conditions for storage of granules.