TY - JOUR
T1 - Effect of stearic acid on the properties of metronidazole/methocel K4M floating matrices
AU - Lara-Hernández, Belem
AU - Hernández-León, Alejandra
AU - Villafuerte-Robles, Leopoldo
PY - 2009/7
Y1 - 2009/7
N2 - The properties of metronidazole/Methocel K4M sustained release floating tablets have been studied varying the proportion of the lubricant, stearic acid, on formulations with and without sodium bicarbonate. The variables studied include technological properties of the tablets such as tablet hardness and ejection pressure, the drug release profile, the hydration kinetics and the floating behaviour. The presence of stearic acid and sodium bicarbonate improves the floating behaviour for more than 8 hours. The hydration volume, the tablet hardness and the ejection pressure decrease as the stearic acid content increases and the polymer content decreases. Drug dissolution increases with increasing proportions of stearic acid and decreasing proportions of the polymer in the tablets. The presence of sodium bicarbonate extends the differences in dissolution produced by stearic acid. These results are attributed to decreasing matrices coherence with an increasing quantity of stearic acid and a reducing polymer proportion. The carbon dioxide bubbles produced by sodium bicarbonate expand the matrices facilitating the dissolution, although their presence obstructs also the diffusion path through the hydrated gel layer.
AB - The properties of metronidazole/Methocel K4M sustained release floating tablets have been studied varying the proportion of the lubricant, stearic acid, on formulations with and without sodium bicarbonate. The variables studied include technological properties of the tablets such as tablet hardness and ejection pressure, the drug release profile, the hydration kinetics and the floating behaviour. The presence of stearic acid and sodium bicarbonate improves the floating behaviour for more than 8 hours. The hydration volume, the tablet hardness and the ejection pressure decrease as the stearic acid content increases and the polymer content decreases. Drug dissolution increases with increasing proportions of stearic acid and decreasing proportions of the polymer in the tablets. The presence of sodium bicarbonate extends the differences in dissolution produced by stearic acid. These results are attributed to decreasing matrices coherence with an increasing quantity of stearic acid and a reducing polymer proportion. The carbon dioxide bubbles produced by sodium bicarbonate expand the matrices facilitating the dissolution, although their presence obstructs also the diffusion path through the hydrated gel layer.
KW - Drugs/release mechanism
KW - Gastric retention
KW - Matrices hydration
KW - Methocel K4M
KW - Metronidazole
KW - Sodium bicarbonate
KW - Stearic acid
KW - Sustained release
UR - http://www.scopus.com/inward/record.url?scp=76149136037&partnerID=8YFLogxK
U2 - 10.1590/S1984-82502009000300016
DO - 10.1590/S1984-82502009000300016
M3 - Artículo
SN - 1984-8250
VL - 45
SP - 497
EP - 505
JO - Brazilian Journal of Pharmaceutical Sciences
JF - Brazilian Journal of Pharmaceutical Sciences
IS - 3
ER -