Zero-Order Release Kinetics from a Self-Correcting Floatable Asymmetric Configuration Drug Delivery System

Abstract

A new approach based on the three-layer matrix technology to control drug release for oral administration is presented. Polyethylene oxide polymers of various molecular weight together with theophylline as drug model and other excipients have been directly compressed into a three-layer asymmetric floatable system. The core layer contains the active drug while external layers with different thickness, composition, and erosion rates are designed to delay the hydration of the middle layer, restrict the early drug diffusion only through cylindrical side surfaces of the tablet, and provide controlled drug release. Results show that during a 16 h dissolution study drug is completely released following the zero-order kinetics with no burst effect. The release rate remains around 0.1 mg min-1 throughout the dissolution study. The release kinetics is independent of changes in pH and compression force but dependent on layer thickness and formulation components. It appears that the operating release mechanism is based on the existence of a balance between the velocities of advancing glassy/rubbery front and erosion at the swollen polymer/dissolution front.

A bioresorbable, polylactide reservoir for diffusional and osmotically controlled drug delivery

“…Implantable delivery systems that provide zero-order drug delivery have the potential for maximizing efficacy while minimizing dose frequency and toxicity [1,2]. Numerous zero-order delivery systems have been developed that are either the matrix type, in which drug is dissolved or dispersed in a solid polymeric matrix [3][4][5][6][7][8][9], or the reservoir type, in which a solid drug core is contained in a rate-controlling polymeric membrane [10][11].…”

Technologies, Optimization and Analytical Parameters in Gastroretentive Drug Delivery Systems

“…For example, multi-layer matrix tablets have been proposed containing an effervescent layer loaded with carbonate and optionally citric acid [53][54][55] . After contact with acidic aqueous media, carbon dioxide is generated and entrapped within the gelling hydrocolloid, causing the system to float.…”

Floating drug delivery systems: A better approach

“…A newer self-correcting floatable asymmetric configuration drug delivery system (Yang and Fassihi, 1996) has a 3-layermatrix to control the drug release. This 3-layer principle has been improved by development of an asymmetric configuration drug delivery system in order to modulate the release extent and achieve zero-order release kinetics by initially maintaining a constant area at the diffusing front with subsequent dissolution/erosion toward the completion of the release process.…”