Assessment of Taste and Grittiness of Riomet^® ER Strawberry, Riomet^® ER Grape, Riomet^® Cherry, and Metformin Immediate-Release Tablets in Healthy Subjects

This study was conducted to evaluate the taste and grittiness of two formulations of Riomet^® ER (metformin hydrochloride for extended release [ER] oral suspension 100 mg/mL) differing only in their flavoring agents (strawberry and grape) in comparison with two commercially available immediate-release (IR) formulations of metformin, Riomet^® Cherry (metformin hydrochloride oral solution 500 mg/5 mL) and metformin IR tablets (metformin hydrochloride IR tablets 500 mg), in healthy human subjects aged 10–70 years.

Five comparison sets (i.e., Riomet^® Cherry vs. Riomet^® ER Strawberry; Riomet^® Cherry vs. Riomet^® ER Grape; metformin IR vs. Riomet^® ER Strawberry; metformin IR vs. Riomet^® ER Grape; and Riomet^® Cherry vs. metformin IR) were evaluated. Riomet^® ER was reconstituted as instructed on the label. Metformin IR tablets were crushed one at a time into a fine powder using a pharmaceutical pill crusher and mixed with 5 mL of water. A 2.5-mL dose of each product was administered to each subject. Subjects were instructed not to swallow any of the products. Each product in the comparison set was rated by the subjects for taste and grittiness according to a 7-point hedonic facial scale and a 5-point level of agreement scale. A comparison questionnaire was also completed by the subjects after evaluating each set. In all, 56 subjects were enrolled and 55 subjects completed the study. The taste preference was statistically evaluated.

All Riomet^® formulations were significantly preferred overall to metformin IR crushed tablets. Both the strawberry and the grape flavors of Riomet^® ER tended to be preferred to Riomet^® Cherry.