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Sustained-release coated pellets containing terbutaline sulfate (TS) 1.8% w/w were prepared. The suitable core formulation that gave round-shape TS pellets was preformulated and was composed of microcrystalline cellulose:lactose 38.61%:57.92%, hydroxypropyl cellulose (HPC-M) 1.67%, and water 40%, respectively. The core pellets containing active drug were coated with various amounts of ethylcellulose (EC) and a combination of EC/HPC-M polymers. The effects of fluidized bed polymeric film coats on drug release were studied in vitro. The dissolution characteristics were also investigated. The release of the active drug decreased as the amount of EC increased. This may be due to water-insoluble EC film, leading to decreased permeability in water. In the case of the combination of EC/HPC-M, the release of the active drug increased as the amount of HPC-M in the coating solution increased. Since HPC-M is a water-soluble polymer, it may be suggested that formation of pores were increased in the coating layer. Among five coating formulas in this study, formulation 1 (F1) (at 1.1% EC concentration) shows a similar dissolution profile to Bricanyl Durules; however, lag time for the release occurred. In conclusion, the formulation that gave an insignificant release profile (p < .01) when compared with commercial product was the capsule containing F1 (at 1.1% EC concentration) mixed with uncoated pellets at a ratio of 7:1, and the release was found to be reproducible.

The purpose of this work was to investigate the effect of different polysulfonate resins and direct compression fillers on physical properties of multiple-unit sustained-release dextromethorphan (DMP) tablets. DMP resinates were formed by a complexation of DMP and strong cation exchange resins, Dowex 50 W and Amberlite IRP69. The tablets consisted of the DMP resinates and direct compression fillers, such as microcrystalline cellulose (MCC), dicalcium phosphate dihydrate (DCP), and spray-dried rice starch (SDRS). Physical properties of tablets, such as hardness, disintegration time, and in vitro release, were investigated. A good performance of the tablets was obtained when MCC or SDRS was used. The use of rod-like and plate-like particles of Amberlite IRP69 caused a statistical decrease in tablet hardness, whereas good tablet hardness was obtained when spherical particle of Dowex 50 W was used. The plastic deformation of the fillers, such as MCC and SDRS, caused a little change in the release of DMP. A higher release rate constant was found in the tablets containing DCP and Dowex 50 W, indicating the fracture of the resinates under compression, which was attributable to the fragmentation of DCP. However, the release of DMP from the tablets using Amberlite IRP69 was not significantly changed because of the higher degree of cross-linking of the resinates, which exhibited more resistance to deformation under compression. In conclusion, the properties of polysulfonate resin, such as particle shape and degree of cross-linking, and the deformation under compaction of fillers affect the physical properties and the drug release of the resinate tablets.

Placebo pellets containing lactose and microcrystalline cellulose (Avicel PH101) ratio 60:40 were prepared by the extrusion-spheronization process. The influence of processing variables, including the spheronizer speed, the spheronization time, the binder type, and the concentration and amount of water content on physical properties of the pellets, were studied. The sphericity of pellets was increased with increasing spheronizer speed during wet mass process. When spheronization time was increased, sphericity, smooth surface, and particle size of pellets were increased. Increasing binder concentration will increase particle size. Pellets using HPC-M as a binder at high spheronizer speeds showed spherical shape, narrow size distribution, and good flow properties when compared with Methocel E-15LV, HPC-L, and Methocel A4M. In addition, increasing HPC-M concentration had no effect on shape and particle size of pellets. The amount of water content was found to affect shape, flow rate, and density. In summary, suitable conditions consisted of 2% w/w of HPC-M, 40% w/w of water, and 15 min of spheronization time at 951 rpm of spheronizer speed.

This study evaluated and compared theophylline pellets prepared by both suspension and powder layering processes using the bottom spray coater and the tangential rotary granulator, respectively. Hydroxypropyl methylcellulose (HPMC) and hydroxypropyl cellulose (HPC) were employed as binders at various concentrations. The pellets were coated with Eudragit RS and RL to various levels. It was found that pellet sizes, true densities, and drug contents were comparable and independent of processes and binder levels. However, the increase in binder resulted in lower porosity and pore size, as well as smoother pellet surface. The powder layered pellets possessed higher pellet density and smoother surface than did the suspension layered pellets due to the greater consolidation resulted from tumbling and colliding of pellets. Powder x-ray diffraction pattern revealed that theophylline present in the suspension layered pellets was a mixture of anhydrous form II and hydrate, indicating that transformation could occur in aqueous medium. Drug release from uncoated pellets was found to be complete within 20 min. For coated pellets, the release was markedly decreased with the increase in Eudragit level. Both film thickness and anhydrous/hydrate form influenced the release of drug from the pellets. In general, two methods of layering produced the pellets of slightly differences in pellet properties; however, changes of drug characteristics could occur in suspension.

The objective of this work was to examine the effect of quaternary polymethacrylate (QPM), a water-insoluble polymer with a positive charge, on the characteristics of the sodium alginate (SA) dispersions and the calcium alginate (CA) gel beads containing propranolol HCl (PPN). The SA-QPM composite dispersions presented the formation of flocculates with a negative charge due to the electrostatic interaction of both substances. The QPM addition did not affect the SA dispersions’ Newtonian flow, but the composite dispersions’ viscosity enhancement was found. The PPN-loaded CA-QPM gel beads had more spherical than the PPN-loaded CA gel beads. The incorporation of QPM caused a bigger particle size, higher drug entrapment efficiency, and greater particle strength of the gel beads. Despite the similar water uptake property, the PPN-loaded CA-QPM gel beads displayed lower burst release and slower drug release rate than the PPN-loaded CA gel beads. However, the drug release from the PPN-loaded CA-QPM gel beads involved drug diffusion and matrix swelling mechanisms. This study demonstrated that adding QPM into the SA dispersions leads to a viscosity synergism. The CA-QPM gel beads display a good potential for use as a bioactive compound delivery system.