Abstract

Background: The spheronization process is a rapidly expanding technology which provides a uniform and predictable transport in the gastrointestinal tract and renders pellets having a good flowability, high mechanical strength, and low friability. Objectives: The aim of the present study was to evaluate the effects of spheronization rate, spheronization time, and moisture content on shape descriptors and physical properties of pellets produced from microcrystalline cellulose (MCC). Methods: Approximately, 50 g of MCC were hydrated, passed through a #8 mesh sieve, and spheronizated at rates of 4, 6, 8, 10, and 12 Hz and residence times of 30, 60, 90, 120, and 180 s in 25 experimental runs. In a separate experimental set, moisture levels of 23.1, 37.5, 47.4, 54.5, and 60% were employed at the optimal operational conditions of 12 Hz and 180 s. A microscopy analysis was used to evaluate the shape descriptors using the ImageJ® software. Pellets properties such as compressibility, friability, true density, strength, flow rate, and mass were also evaluated. A multivariate analysis was used to study the effect of these production variables on response variables such as shape descriptors, densification, breaking strength, friability, and porosity. Results: Pellets having a large size were obtained employing a high spheronization rate, spheronization time, and high moisture content. Shape descriptors related to size such as area, perimeter, and mean diameter increased with increasing spheronization time and spheronization rate. Further, pellets obtained at a high spheronization rate were more spherical than those obtained at low speeds. Conversely, shape descriptors related to morphology such as circularity and roundness and pellet strength remained virtually unchanged as operational conditions changed. Conclusions: The moisture level was the most critical factor to increase pellet size and improved the spherical morphology. On the other hand, spheronization rate was the determining factor for pellet properties such as densification, compressibility, and compactibility.