Influence of an Acrylic Polymer Blend on the Physical Stability of Film-Coated Theophylline Pellets

Abstract

Abstract. The purpose of this study was to investigate the physical stability of a coating system consisting of a blend of two sustained release acrylic polymers and its influence on the drug release rate of theophylline from coated pellets. The properties of both free films and theophylline pellets coated with the polymer blend were investigated, and the miscibility was determined via differential scanning calorimetry. Eudragit ® RS 30 D was plasticized by the addition of Eudragit ® NE 30 D, and the predicted glass transition temperature (T g ) of the blend was similar to the experimental values. Sprayed films composed of a blend of Eudragit ® NE 30 D/Eudragit ® RS 30 D (1:1) showed a water vapor permeability six times greater than films containing only Eudragit ® NE 30 D. The presence of quaternary ammonium functional groups from the RS 30 D polymer increased the swellability of the films. The films prepared from the blend exhibited stable permeability values when stored for 1 month at both 25°C and 40°C, while the films which were composed of only Eudragit ® NE 30 D showed a statistically significant decrease in this parameter when stored under the same conditions. Eudragit ® NE 30 D/Eudragit ® RS 30 D (1:1)-sprayed films decreased in elongation from 180% to 40% after storage at 40°C for 1 month, while those stored at 25°C showed no change in elongation. In coated pellets, the addition of Eudragit ® RS 30 D to the Eudragit ® NE 30 D increased the theophylline release rate, and the pellets were stable when stored at 25°C for a period of up to 3 months due to maintenance of the physico-mechanical properties of the film. Pellets stored at 40°C exhibited a decrease in drug release rate over time as a result of changes in film physico-mechanical properties which were attributed to further coalescence and densification of the polymer. When the storage temperature was above the T g of the composite, instabilities in both drug release rate and physical properties were evident. Stabilization in drug release rate from coated pellets could be correlated with the physico-mechanical stability of the film formulation when stored at temperatures below the T g of the polymer.

Formulation considerations in the design of topical, polymeric film-forming systems for sustained drug delivery to the skin

“…Film flexibility is clearly of importance and a polymer T g below that of a typical skin surface temperature (~32°C) is therefore logical. The polymer, Eudragit NE, has a T g of 13°C and creates flexible films (35). The T g of Eudragit RS, on the other hand, is ~65°C (35;36) and requires formulation with a plasticiser to render it appropriately flexible for use on the skin.…”

In vitro dissolution of proton-pump inhibitor products intended for paediatric and geriatric use in physiological bicarbonate buffer

“…This polymer has a very low glass 337 transition temperature of 13°C and can be used in polymer blends with other acrylic 338 polymers to decrease glass transition temperature and thus increase film flexibility (Y. 339 El-Malah and S. Nazzal, 2008;S. Kucera et al, 2009).…”

Preparation and Characterization of a Novel Aqueous Dispersion for Enteric Coating of Pantoprazole Sodium Pellets

“…Enteric coating materials are generally non-toxic, chemically inert, and relatively stable; they do not react with the drug and can be dissolved or uniformly dispersed in a certain medium. These enteric coating materials usually have excellent wet insulation, protect from light and have airtight effects (1)(2)(3). The enteric-coated products currently available on the market are organic polymer solutions (Eudragit ® L100-55) and aqueous polymer dispersions (Eudragit ® L30D-55).…”

“…Eudragit ® L30D-55 aqueous polymer dispersions are prepared by the emulsion polymerization method without addition of other excipients. It is necessary to add a plasticizer to the dispersion during the MIN HAN 1,2 QIN YU 1 XUERONG LIU 1 FUQIANG HU 1, * HONG YUAN 1, * coating process (4). Mechanisms of film formation of aqueous dispersions and organic solutions are different (5)(6)(7)(8).…”