TY - JOUR
T1 - Effect of sodium bicarbonate on the properties of metronidazole floating matrix tablets
AU - Gutiérrez-Sánchez, Pablo Emilio
AU - Hernández-León, Alejandra
AU - Villafuerte-Robles, Leopoldo
PY - 2008/2
Y1 - 2008/2
N2 - The effect of sodium bicarbonate (SB) on the swelling behavior and the sustained release of floating systems was studied with varied proportions of this excipient and metronidazole. Two polymers with different hydration characteristics, Methocel K4M and Carbopol 971P NF, were used to formulate the matrices. Under in vitro dissolution conditions, the addition of SB to metronidazole sustained-release tablets modifies the matrix hydration volume, increasing at the beginning, reaching a maximum, and then declining. Pure Carbopol matrices show a rapid hydration with a limited further effect of the SB and metronidazole loads. Methocel show a significant increase of the apparent hydration volume due to SB addition with no further notable change due to metronidazole load. Increasing the metronidazole load reduces the floating time of Carbopol matrices while no effect on Methocel matrices could be observed within 8 hours dissolution. Matrices show increasing release constant values (k) as the metronidazole load increases. Methocel matrices release the drug 10% to 15% faster than Carbopol matrices. SB increases the cumulative amount of drug released from Methocel but not that releasing from Carbopol. These results are attributed to the intrinsic polymer properties, the barrier effect of CO2 bubbles, and the matrix volume expansion produced after addition of SB.
AB - The effect of sodium bicarbonate (SB) on the swelling behavior and the sustained release of floating systems was studied with varied proportions of this excipient and metronidazole. Two polymers with different hydration characteristics, Methocel K4M and Carbopol 971P NF, were used to formulate the matrices. Under in vitro dissolution conditions, the addition of SB to metronidazole sustained-release tablets modifies the matrix hydration volume, increasing at the beginning, reaching a maximum, and then declining. Pure Carbopol matrices show a rapid hydration with a limited further effect of the SB and metronidazole loads. Methocel show a significant increase of the apparent hydration volume due to SB addition with no further notable change due to metronidazole load. Increasing the metronidazole load reduces the floating time of Carbopol matrices while no effect on Methocel matrices could be observed within 8 hours dissolution. Matrices show increasing release constant values (k) as the metronidazole load increases. Methocel matrices release the drug 10% to 15% faster than Carbopol matrices. SB increases the cumulative amount of drug released from Methocel but not that releasing from Carbopol. These results are attributed to the intrinsic polymer properties, the barrier effect of CO2 bubbles, and the matrix volume expansion produced after addition of SB.
KW - Carbopol 971P NF
KW - Floating tablets
KW - Methocel K4M
KW - Metronidazole
KW - Polymer hydration
KW - Sustained release
UR - http://www.scopus.com/inward/record.url?scp=39849093430&partnerID=8YFLogxK
U2 - 10.1080/03639040701506478
DO - 10.1080/03639040701506478
M3 - Artículo
SN - 0363-9045
VL - 34
SP - 171
EP - 180
JO - Drug Development and Industrial Pharmacy
JF - Drug Development and Industrial Pharmacy
IS - 2
ER -