Pharmaceutical characterization of xerogel pill with various gelling agents as a multiple-unit dosage form for pediatric and geriatric patients

Abstract

The “xerogel pill” composed of an inner drug core and an outer dried-gel layer has been developed in our previous work. The aim of this study was to characterize the pharmaceutical properties of the xerogel pill with various gelling agents such as xanthan gum (XG), carboxyvinyl polymer (CVP) and hydroxypropyl methylcellulose (HPMC). The internal (central) fluid of the fexofenadine hydrochloride (FXF) nanosuspension and the external (peripheral) fluid of the gelling-agent solution were separately fed to a two-fluids nozzle and concentrically co-dropped into liquid nitrogen. The xerogel pills were formed after the freeze-drying process. The pill with any composition ratios of the inner drug core and the outer dried-gel layer could be freely prepared by changing the feeding rates of the central and peripheral fluids. Further, any pills composed of XG, CVP or HPMC could be also successfully prepared in high recovery of unbroken pills with keeping their spherical shape. The pill size was in the range of 4.0–6.5 mm and dependent on the visco-elastic properties of the peripheral fluid dissolved gelling agent. These pills were found to be porous spheres having a low density and a double-layer structure covered with a thin shell. When the pills were placed on a wet filter, water immediately penetrated into the inside pills through the pore, and the surface of them rapidly transformed to a gel. The xerogel pill showed rapid dissolution up to 50% of FXF and then reach plateau at 70–100% within 60 min. A sliding test using a creep meter was established to evaluate swallowing performance, in which the horizontal force was detected during sliding under applying vertical load. It was found that the xerogel pill had smooth-sliding profile comparing to the conventional tablet or capsule. The results in this report demonstrate that the present xerogel pill would be a potential dosage form for pediatric and geriatric use.