sodium-bicarbonate and ethyl-cellulose

Topics: Acrylic Resins; Antineoplastic Agents; Cellulose; Humans; Quinolines; Sodium Bicarbonate; Spectroscopy, Fourier Transform Infrared; Tablets

The aim of this research was to formulate effervescent floating drug delivery systems of theophylline using different release retarding polymers such as ethyl cellulose, Eudragit® L100, xanthan gum and polyethylene oxide (PEO) N12K. Sodium bicarbonate was used as a gas generating agent. Direct compression was used to formulate floating tablets and the tablets were evaluated for their physicochemical and dissolution characteristics. PEO based formulations produced better drug release properties than other formulations. Hence, it was further optimized by central composite design. Further subjects of research were the effect of formulation variables on floating lag time and the percentage of drug released at the seventh hour (D7h). The optimum quantities of PEO and sodium bicarbonate, which had the highest desirability close to 1.0, were chosen as the statistically optimized formulation. No interaction was found between theophylline and PEO by Fourier Transformation Infrared spectroscopy (FTIR) and Differential Scanning Calorimetry (DSC) studies.

Topics: Calorimetry, Differential Scanning; Cellulose; Chemistry, Pharmaceutical; Drug Carriers; Drug Delivery Systems; Drug Liberation; Excipients; Polyethylene Glycols; Polymers; Polymethacrylic Acids; Polysaccharides, Bacterial; Sodium Bicarbonate; Solubility; Spectroscopy, Fourier Transform Infrared; Tablets; Theophylline

The purpose of the present study was to prepare floating matrix tablets of clarithromycin employing simplex lattice design. Hydroxypropyl methylcellulose (HPMC) and Ethyl Cellulose (EC) were used as matrix forming agents; sodium bicarbonate and citric acid as effervescence producing agents. Simplex lattice design was used as optimization technique employing three independent formulation variables viz. concentration of HPMC (X1), Citric Acid (X2), EC (X3) whereas floating lag time, t50%, t90%, and MDT (Mean Dissolution Time) were the response (dependent) variables. Seven formulations (F1-F7) were prepared and evaluated for dissolution studies, floating characteristics, weight variation, hardness, thickness, friability.t50% of the formulations was found to be ranging from 317±2.54 to 522±2.39 minutes. The t90% and MDT of the tablets were found to be ranging between 659.65±1.89 to 967.35±1.67 minutes and 527.20±1.22 to 846.78±2.61 minutes respectively. Total floating time of the formulations was more than 12 hours and the drug content was in the range of 98.54±0.46 to 99.92±0.32. The amount of both HPMC and EC were found to play a dominating role in controlling the release of the drug from the formulation whereas ratios of sodium bicarbonate and citric acid were showing significant effect on the floating lag time. The release exponent (n) from Korsmeyer-Peppas model was found to be between 0.62 and 0.75 indicating non-Fickian or anomalous drug release behavior from the formulated floating matrix tablets. Simplex lattice design was reported to be an effective optimization technique for optimizing pharmaceutical formulations against desired responses.

Topics: Anti-Bacterial Agents; Carbon Dioxide; Cellulose; Chemistry, Pharmaceutical; Citric Acid; Clarithromycin; Computer Simulation; Delayed-Action Preparations; Excipients; Hardness; Hypromellose Derivatives; Kinetics; Models, Chemical; Numerical Analysis, Computer-Assisted; Sodium Bicarbonate; Solubility; Tablets; Technology, Pharmaceutical

Effervescent multiple-unit floating drug delivery systems (muFDDSs) consisting of drug (lorsartan)- and effervescent (sodium bicarbonate)-containing pellets were characterized in this study. The mechanical properties (stress and strain at rupture, Young's modulus, and toughness) of these plasticized polymeric films of acrylic (Eudragit RS, RL, and NE) and cellulosic materials (ethyl cellulose (EC), and Surelease) were examined by a dynamic mechanical analyzer. Results demonstrated that polymeric films prepared from Surelease and EC were brittle with less elongation compared to acrylic films. Eudragit NE films were very flexible in both the dry and wet states. Because plasticizer leached from polymeric films during exposure to the aqueous medium, plasticization of wet Eudragit RS and RL films with 15% triethyl citrate (TEC) or diethyl phthalate (DEP) resulted in less elongation. DEP might be the plasticizer of choice among the plasticizers examined in this study for Eudragit RL to provide muFDDSs with a short time for all pellets to float (TPF) and a longer period of floating. Eudragit RL and RS at a 1∶1 ratio plasticized with 15% DEP were optimally selected as the coating membrane for the floating system. Although the release of losartan from the pellets was still too fast as a result of losartan being freely soluble in water, muFDDSs coated with Eudragit RL and RS at a 1∶1 ratio might have potential use for the sustained release of water-insoluble or the un-ionized form of drugs from gastroretentive drug delivery systems.

Topics: Cellulose; Delayed-Action Preparations; Drug Carriers; Losartan; Membranes, Artificial; Plastics; Sodium Bicarbonate; Stress, Mechanical

The purpose of this research was to develop a novel gastroretentive multiparticulate system with floating ability. This system was designed to provide drug-loaded pellets coated with three successive coatings-the retarding film (ethyl cellulose), the effervescent layer (sodium bicarbonate) and the gas-entrapped polymeric membrane (Eudragit RL 30D). The floating pellets were evaluated for SEM, floating characteristic parameters, in vitro release and bioavailability in New Zealand rabbits. The zero-order release theory model is designed to interpret the release processes. Due to the swelling property, high flexibility and high water permeability, Eudragit RL 30D was used as a gas-entrapped polymeric membrane. The obtained pellets exhibit excellent floating ability and release characteristics. Analysis of the release mechanism showed a zero-order release for the first 8h because of the osmotic pressure of the saturated solution inside of the membrane, which was in accordance with that predicted. Abdominal X-ray images showed that the gastroretention period of the floating barium sulfate-labeled pellets was no less than 6h. The relative bioavailability of the floating pellets compared with reference tablets was 113.06 ± 23.83%. All these results showed that the floating pellets are a feasible approach for the gastroretentive drug delivery system.

Topics: Acrylic Resins; Administration, Oral; Animals; Anti-Bacterial Agents; Biological Availability; Cellulose; Chemistry, Pharmaceutical; Chromatography, Liquid; Drug Compounding; Excipients; Gastrointestinal Tract; Microscopy, Electron, Scanning; Models, Chemical; Ofloxacin; Permeability; Rabbits; Radiography; Sodium Bicarbonate; Solubility; Surface Properties; Tablets, Enteric-Coated; Tandem Mass Spectrometry; Technology, Pharmaceutical