orabase and aluminum-magnesium-silicate

Metoprolol succinate (MS) gastroretentive (GR) controlled release system was formulated to increase gastric residence time leading to improved drug bioavailability. Box-Behnken model was followed using novel combinations of sodium alginate (SA), sodium carboxymethylcellulose (NaCMC), magnesium alumino metasilicate (MAS) as independent variables. Floating lag time (Flag), t25, t50, t75, diffusion exponent as dependent variables revealed that the amount of SA, NaCMC and MAS have a significant effect (p < 0.05) on t25, t50, t75 and Flag. MSGR tablets were prepared and evaluated for mass, thickness, hardness, friability, drug content and floating property. Tablets were studied for dissolution for 24 h and exhibited controlled release of MS with floating for 16 h. The release profile of the optimized batch MS01 fitted first-order kinetics (R2 = 0.9868, n = 0.543), indicating non-Fickian diffusion or anomalous transport by diffusion and swelling.

Topics: Administration, Oral; Alginates; Aluminum Compounds; Aluminum Silicates; Biological Availability; Carboxymethylcellulose Sodium; Computer Simulation; Diffusion; Drug Carriers; Drug Compounding; Drug Delivery Systems; Gastric Emptying; Glucuronic Acid; Hexuronic Acids; Humans; Magnesium; Magnesium Compounds; Metoprolol; Silicates; Solubility; Tablets

The aims of this study were to characterize the morphology and size of flocculates and the zeta potential and rheological properties of polymer-magnesium aluminum silicate (MAS) composite dispersions and to investigate the physical properties of acetaminophen (ACT) suspensions prepared using the composite dispersions as a flocculating/suspending agent. The polymers used were sodium alginate (SA), sodium carboxymethylcellulose (SCMC), and methylcellulose (MC). The results showed that SA, SCMC, and MC could induce flocculation of MAS by a polymer-bridging mechanism, leading to the changes in the zeta potential of MAS and the flow properties of the polymer dispersions. The microscopic morphology and size of the flocculates was dependent on the molecular structure of the polymer, especially ether groups on the polymer side chain. The residual MAS from the flocculation could create a three-dimensional structure in the SA-MAS and SCMC-MAS dispersions, which brought about not only an enhancement of viscosity and thixotropic properties but also an improvement in the ACT flocculating efficiency of polymers. The use of polymer-MAS dispersions provided a higher degree of flocculation and a lower redispersibility value of ACT suspensions compared with the pure polymer dispersions. This led to a low tendency for caking of the suspensions. The SCMC-MAS dispersions provided the highest ACT flocculating efficiency, whereas the lowest ACT flocculating efficiency was found in the MC-MAS dispersions. Moreover, the added MAS did not affect ACT dissolution from the suspensions in an acidic medium. These findings suggest that the polymer-MAS dispersions show good potential for use as a flocculating/suspending agent for improving the rheological properties and physical stability of the suspensions.

Topics: Acetaminophen; Alginates; Aluminum Compounds; Carboxymethylcellulose Sodium; Drug Stability; Flocculation; Glucuronic Acid; Hexuronic Acids; Magnesium Compounds; Methylcellulose; Particle Size; Polymers; Silicates; Solubility; Suspensions

Topics: Aluminum Compounds; Aluminum Silicates; Carboxymethylcellulose Sodium; Contraceptive Agents, Female; Gels; Magnesium Compounds; Pharmaceutical Vehicles; Silicates; Viscosity

Topics: Aluminum Compounds; Aluminum Silicates; Carboxymethylcellulose Sodium; Contraceptive Agents, Female; Magnesium Compounds; Pharmaceutical Vehicles; Silicates; Sodium Dodecyl Sulfate; Viscosity