Effect of formulation variables on oral grittiness and preferences of multiparticulate formulations in adult volunteers

Multiparticulate formulations are composed of multiple solid dosage units which can be administered directly to the mouth or sprinkled on food. Oral grittiness (i.e. rough mouthfeel) may arise from the presence of particles in the mouth, limiting palatability. In this work, multiparticulate formulations were prepared by dispersion of spherical granules into orange flavoured vehicles thickened with hypromellose (HPMC) at different viscosities in order to assess oral perception of grittiness by a panel of thirty adults through direct scaling on a 100 mm visual analogue scale. The effect of formulation factors such as particle size (90, 127, 263 mu m), amount of particles per 10 ml (0.25, 0.50, 1.00 g) and viscosity of the vehicle (0.08, 0.43, 2.80 Pas) were investigated. Grittiness was increasingly perceived with increasing amount and size of particles. Increasing viscosity of the administration media had a masking effect on the perception of particles. Less gritty samples were generally regarded as 'more pleasant' by the participants of the study. However, samples dispersed in thickened vehicles seemed to be less preferred despite being less gritty; which could be ascribed to an unpleasant mouthfeel of the vehicle. In the design of multiparticulate formulations acceptable for a targeted patient group all these formulation factors will need to be considered and optimised. (C) 2016 The Authors. Published by Elsevier B.V.