A feasibility study on pellet coating using a high-speed quasi-continuous coater

10.1208/s12249-012-9852-xAAPS PharmSciTech1341276-128

Influence of operational variables on properties of piroxicam pellets prepared by extrusion-spheronization: A technical note

The processing conditions has a pronounced effect on the pellet properties. Drying conditions influenced the mean size and the drug release of the pellets. Because of the shrinking of the pellets upon drying at higher temperatures, the pellets also showed increased densities. Freeze drying almost prevented shrinking and thus led to the highest drug release. With an increase in the temperature of drying, the drug release rate decreased

Comparison of Release-Controlling Efficiency of Polymeric Coating Materials Using Matrix-type Casted Films and Diffusion-Controlled Coated Tablet

Polymeric coating materials have been widely used to modify release rate of drug. We compared physical properties and release-controlling efficiency of polymeric coating materials using matrix-type casted film and diffusion-controlled coated tablet. Hydroxypropylmethyl cellulose (HPMC) with low or high viscosity grade, ethylcellulose (EC) and Eudragit® RS100 as pH-independent polymers and Eudragit S100 for enteric coatings were chosen to prepare the casted film and coated tablet. Tensile strength and contact angle of matrix-type casted film were invariably in the decreasing order: EC> Eudragit S100> HPMC 100000> Eudragit RS100>HPMC 4000. There was a strong linear correlation between tensile strength and contact angle of the casted films. In contrast, weight loss (film solubility) of the matrix-type casted films in three release media (gastric, intestinal fluid and water) was invariably in the increasing order: EC < HPMC 100000 < Eudragit RS100 < HPMC 4000 with an exception of Eudragit S100. The order of release rate of matrix-type casted films was EC > HPMC 100000 > Eudragit RS100 > HPMC 4000 > Eudragit S100. Interestingly, diffusion-controlled coated tablet also followed this rank order except Eudragit S100 although release profiles and lag time were highly dependent on the coating levels and type of polymeric coating materials. EC and Eudragit RS100 produced sustained release while HPMC and Eudragit S100 produced pulsed release. No molecular interactions occurred between drug and coating materials using 1H-NMR analysis. The current information on release-controlling power of five different coating materials as matrix carrier or diffusion-controlled film could be applicable in designing oral sustained drug delivery

Chemical stabilization of a Δ9-tetrahydrocannabinol prodrug in polymeric matrix systems produced by a hot-melt method: Role of microenvironment pH

This research was conducted in order to fabricate stable polyethylene oxide (PEO)-based transmucosal systems of a Δ9-tetrahydrocannabinol (THC) prodrug, a hemisuccinate ester, using a hot-melt method. Since Δ9-tetrahydrocannabinol (THC-HS) was heat labile, a series of processing aids were evaluated in order to facilitate hot-melt production at lower temperatures, thereby reducing THC-HS degradation. The stability of THC-HS was influenced both by the processing conditions such as heating time and temperature, and the postprocessing storage conditions. The type of formulation additive also affected the extent of degradation. In the presence of polyethylene glycol (PEG)-400, the percentage of relative degradation of THC-HS to THC was 13.5% and 49.4% at 80°C and 120°C, respectively. In contrast, incorporation of vitamin E succinate (VES) reduced processing degradation to 2.1% and 9.2%, respectively, under the same conditions. Severe degradation of THC-HS was observed during storage, even under freezing conditions (−18°C). A VES-Noveon AA-1 combination was observed to best stabilize the prodrug systems both during processing and postprocessing. Stabilization of THC-HS was achieved in these polyethylene oxide matrices at 4°C, with almost 90% of theoretical drug remaining for up to 8 months. Investigation of the pH effect revealed that the pH of the microenvironment in these polymeric systems could be modulated to significantly improve the stability of THC-HS, degradation being the least in a relatively acidic medium

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

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 (Tg) 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 Tg 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 Tg of the polymer

Influence of starting material particle size on pellet surface roughness

10.1208/s12249-013-0031-5AAPS PharmSciTech151131-13