Taste-masked properties of micropellets based on hard fat and/or solid lipid mixtures (prepared by solvent-free cold extrusion/spheronization), containing metformin hydrochloride were investigated. An in-line and an on-line drug release profile evaluation of the pellets was performed and further correlated with an electronic tongue investigation. The pellets based on more than 30% of lipid binders showed metformin HCl releases below 10% after 30 s of dissolution. Micropellets based on 20 and 30% of lipids showed immediate drug release profiles. Likewise, the electronic tongue assay showed a decrease in the sensor responses related to the increase of lipid amount in the formulations denoting a significant improvement in the taste masking properties of pellets based on more than 30% of lipid binders. A slight difference between pellets based on hard fat only and pellets based on ternary lipid mixtures was evidenced. Solvent-free cold extrusion/spheronization using solid lipids showed to be a robust method to obtain high drug loaded metformin HCl micropellets with adequate taste-masked properties and immediate drug release profile.
