Design of easily swallowable xerogel pill with enough physical strength through hardening-process under heating and humidification

The xerogel pill has been developed as a novel dosage form with dose-adjusting and swallow-assisting functions by using drop freeze-drying (DFD) technique. It was double-structured small sphere composed of an inner drug core and an outer dried-gel layer, however, had problem of insufficient physical strength. In this study, it was attempted to use dextrin (DEX), one of oligosaccharides, to strengthen the xerogel pill. DEX was co-dissolved in the dropping fluid in the DFD process and co-loaded in the conventional pill, which was mainly composed of mannitol (MNT) as a filler, to prepare the rigid body. DEX-loaded pill could be successfully prepared with high recovery (>90 %) by optimizing the ratio of DEX and MNT.

Further, the representative pills with and without DEX (P-DEX and P-MNT, respectively) were hardening-processed under humidification. The physical strength of P-DEX pill was significantly increased when humidified under severe condition, resulting in enough hardness (>5N) and friability (<1.0 %). Processed P-DEX was found to have dense structure covered with a thick outer shell, which would be formed by interparticle bridge of DEX. It was also found that processed P-DEX pill suppressed initial drug dissolution significantly and exhibited sustained dissolution behavior, suggesting the potential function of bitter taste masking.

Processed P-DEX pill had excellent sliding behavior with low friction forces as a result of lubricant effect of xanthan gum (XG) surrounding the pills. Furthermore, the sliding test also suggested that processed P-DEX pill had hard candy-like texture, in contrast unprocessed P-DEX pill had orally disintegrating (OD) tablet-like texture. Various xerogel pills with such different swallowing texture would have a potential to accommodate the children’s preferences when taking medication.

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Fexofenadine hydrochloride (FXF), anti-allergic drug, was used as a poorly water-soluble model drug. FXF was purchased from Osaka Synthetic Chemical Laboratories, Inc. (Nishinomiya, Japan). Polyvinylpyrrolidone (PVP) as a water-soluble polymer and poloxamer (POX) as a surfactant were applied as milling promotor. PVP (Kollidon 30) and POX (Kolliphor P188) were provided by BASF Japan Ltd. (Tokyo, Japan). Xanthan gum (XG) was used as gelling agent in the external fluid.

Rando Asai, Keita Kondo, Rina Kato, Kiyoka Kajiwara, Toshiyuki Niwa, Design of easily swallowable xerogel pill with enough physical strength through hardening-process under heating and humidification, International Journal of Pharmaceutics, 2024, 124282, ISSN 0378-5173,

Read also our introduction article on Disintegrants here:

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