ABSTRACT
The aim of this work is the assessment of the eventual enhancing effects of Carbopol 971P NF on the performance of Benecel K4M as a controlled release agent and its impact on other technological properties such as compactibility and powder flowability. The effect of Carbopol 971P NF and Benecel K4M in the performance of metronidazole tablets with controlled release was assessed using dissolution and compactibility profiles and the flowability of powders. Benecel K4M produces release profiles with an average exponent n=0.711 while Carbopol 971P NF displays average values of n=1.19. The values for tablets containing equal parts of Carbopol 971P NF and Benecel K4M was an average of n=0.947. Metronidazole tablets containing the Benecel K4M/Carbopol 971P NF blend shows a compactibility 2-3 times higher than tablets containing only Benecel K4M. Metronidazole/Benecel K4M blends flow sufficiently at all studied polymer proportions (≤ 30%) while admixtures of metronidazole/Benecel K4M with Carbopol 971P NF flow sufficiently only at polymer proportions ≤ 17%. Carbopol 971P NF enhances the overall performance of Benecel K4M in the same way as Noveon AA1 does, it reduces better the drug release and improves the compactibility, although decreases the flowability.
ABSTRACT
The objective of this study was the evaluation of different types of lactose on the powders flow properties and dissolution of tablets of formulations with captopril and amoxicillin. Data of powders flow rate, compressibility index and dissolution profiles of tablets are presented. The powders flow rate showed higher sensitivity to small changes in their properties, compared to compressibility index. SuperTabs 21AN and 24AN flow at least 20 times faster than Lactopress and lactose NF. Lubrication increases the flow rate, maintaining the observed comparative differences. Dilution of lactoses with 50% captopril or amoxicillin reduces drastically the powder flow, producing also an equalizing effect. The greater flowability of SuperTabs, compared to other types of lactose, practically disappears. Dissolution of lubricated and unlubricated lactose tablets show a much faster dissolution of SuperTab 21AN tablets followed by Lactopress, lactose NF and SuperTab 24AN tablets. Dilution of lactoses with 50% captopril displays a quite smaller dissolution rate with a comparative similar behavior as observed before while dilution with amoxicillin show an equalizing effect of drug dissolution with minor differences between lactoses. The effect of lactose excipients on dissolution is attributed in a greater extent to mechanical properties of their tablets than to differences in solubility and dissolution.
ABSTRACT
This work aimed the assessment of the effect of different proportions of Noveon AA1 on performance of HPMC as a controlled release agent for direct compression tablets. The functionality of polymer blends was determined using dissolution profiles, compactibility profiles and the powders compressibility index. Ten percent HPMC allows a metronidazole release after 3 h of 85%, an exponent n=0.48 and a release constant K=6.9. The increasing polymer substitution by Noveon AA1 decreases drug dissolution up to 36%, increases the exponent to 1.0 and decreases the release constant to 0.2%. The metronidazole/HPMC blend shows a slower increasing and a lower potential of tablets compactibility (20 N) while its increasing substitution by Noveon AA1 attains faster increasing and higher potential compactibilities (39 N). The metronidazole/HPMC (90:10) blend shows a low compressibility index (14%) that increases up to 33.2% with increasing Noveon AA1 proportions. Noveon AA1 proportions ≤ 5% display good/passable powder flowabilities. Noveon AA1 enhances the overall controlled release performance of HPMC, inducing zero order release patterns without lag or burst effects and reducing drug release more efficiently. Noveon AA1 also improves the compactibility of metronidazole/HPMC blends, however, decreases their flowability; flowability is acceptable only at lesser polymer proportions.
ABSTRACT
The purpose of the work is the comparative evaluation of GalenIQ 721, against known excipients such as Pharmatose M200 and Alfacel type 102. The evaluated parameters included compactibility curves, tablet ejection pressure, disintegration time and flowability of individual powders and mixtures of the excipients and amoxicillin. The surrogate and explicit compactibility of Alfacel 102 (492 N; 7.9 N) is superior, followed by GalenIQ 721 (310 N; 0.93 N) and Pharmatose M200 (203 N; -2.8 N). The lubricity of Alfacel 102 is superior (ejection pressure - Pe=0.590 MPa), followed by GalenIQ 721 (Pe=6.45 MPa) and Pharmatose M200 (Pe=6.51 MPa). Disintegrability of tablets was better by GalenIQ (0.33 s/N), followed by Alfacel 102 (2.48 s/N) and Pharmatose M200 (4.47 s/N).GalenIQ 721 displays a powder fluidity of (14.4 g/s), followed by Alfacel 102 (7.88 g/s) and Pharmatose M200 (0.99 g/s). The tableting functionality of GalenIQ 721 is better than that of Pharmatose M200 but inferior of that of Alfacel 102. Although the GalenIQ 721 characteristics, predominantly brittle, are expected to be more stable to changes in formula composition and process conditions than those of Alfacel 102, plastic behavior.
ABSTRACT
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.
Estudaram-se as propriedades de comprimidos flutuantes de metronidazol/Methocel K4M de liberação controlada, variando-se a proporção do lubrificante, ácido esteárico, nas formulações com e sem bicarbonato de sódio. As variáveis estudadas incluem propriedades tecnológicas dos comprimidos, tais como dureza, pressão de ejeção, perfil de liberação do fármaco, cinética de hidratação e comportamento de flutuação. A presença de ácido esteárico e do bicarbonato de sódio melhora o comportamento de flutuação para mais de 8 horas. O volume de hidratação, a dureza e a pressão de ejeção do comprimido decrescem à medida que o conteúdo de ácido esteárico e de polímero diminui. A dissolução do fármaco aumenta com o aumento das proporções de ácido esteárico e a diminuição das proporções de polímero nos comprimidos. A presença de bicarbonato de sódio amplia as diferenças na dissolução produzidas pelo ácido esteárico. Estes resultados são atribuídos à coesão decrescente das matrizes, com o aumento da quantidade de ácido esteárico e a redução da proporção de polímero. Bolhas de dióxido de carbono produzidas pelo bicarbonato de sódio expandem as matrizes, facilitando a dissolução, embora a presença delas obstrua, também, a difusão através da camada de gel hidratado.