Influence of calcium carbonate and sodium carbonate gassing agents on pentoxifylline floating tablets properties

Abstract

Purpose: this study was to design and evaluate effervescent floating tablets with sustained release behaviour. Pentoxifylline is a water-soluble model drug with a short half-life, consequently developing sustained release preparations would be beneficial. Methods: a binary (1:1) mixture of sodium alginate and hydroxyethyl cellulose containing pentoxifylline, with either 10% or 20% calcium carbonate or sodium carbonate, was used to prepare floating tablets. Results: tablets floated on the surface of the dissolution medium, showed an adequate floating lag time, and floated for more than 12 hours. Tablets manufactured from granules with 20%(w/w) calcium carbonate were promising with respect to their floating lag time (~7min), floating duration (>24 hours), sustained drug release rate, and swelling ability. An in vivo study of these promising tablets and a reference solution of pentoxifylline were investigated following oral administration of 5.75±0.15mg in rats. Compared with the reference solution, the pharmacokinetic parameters changed significantly (p<0.05); the Cmax of the tablets was decreased (945.32ng/ml versus 2552.30ng/ml for the solution), while the Tmax and t1/2 were prolonged. Conclusion: the study shows that a binary mixture of hydroxyethyl cellulose and sodium alginate, together with 20%(w/w) calcium carbonate, offers an exciting opportunity to develop sustained release pentoxifylline preparations.

Effects of Formulation and Process Variables on Gastroretentive Floating Tablets with A High-Dose Soluble Drug and Experimental Design Approach

“…In the case of non-effervescent systems, highly swellable cellulose derivatives or gel-forming polymers are used, which is preferable for potent drugs [ 13 , 14 , 15 ]. However, in effervescent systems, gas generating agents, such as sodium bicarbonate and calcium carbonate are used, which generate CO 2 gas upon contact with gastric fluid, and eventually reduce the bulk density of tablets [ 16 , 17 , 18 , 19 ].…”

Gastroretentive Technologies in Tandem with Controlled-Release Strategies: A Potent Answer to Oral Drug Bioavailability and Patient Compliance Implications

“…Effervescent systems contain a gas-forming agent and/or volatile liquids that contribute to their floatation. In a gas-generating floating system, swellable polymers are mixed with effervescent agents such as sodium bicarbonate, calcium carbonate, tartaric acid, and citric acid used alone or in combinations [10,16,102]. Upon contact of the system with gastric fluids, the gas-generating agent reacts with hydrochloric acid and CO 2 gas is generated.…”

Current State and Future Perspectives on Gastroretentive Drug Delivery Systems

“…This approach has been applied for single- and multiple-unit systems. In the gas-generating floating system, effervescent agents such as sodium bicarbonate, calcium carbonate, tartaric acid, and citric acid are used in combination with hydrophilic polymers [9,70]. When this system comes into contact with gastric fluid, CO 2 is liberated due to the reaction of the effervescent agent with gastric fluid.…”