[Development of patient-friendly preparations(II): Preparation and characterization of carrageenan gel containing...

The pharmaceutical utility of the allopurinol gel (APNgel) which consists of allopurinol (APN), carrageenan (kappa-CG or iota-CG) and polyethylene (oxide) (Alkox) was investigated as a possible material for an oral dosage preparation for ease in handling and/or swallowing. The gel formation was studied as a function of a variety of the concentration of Alkox and/or CG added. The APNgel gelled with kappa-CG was not appropriate to the oral dosage form because of its original taste and odor. In contrast, since iota-CG has no odor and/or taste, we added iota-CG as a gel material. From the investigation of the gelation behavior and the handling of the gelled material, the preferred composition of APNgel (Alkox: iota-CG% ratio) seemed to be that of 0.5:2.0, 1.0:2.0 and 2.0:2.0. The gel strength and the in vitro assessment of the adhesiveness of APNgels were evaluated using a creep meter. The gel strength of the APNgel was affected by the amount of the added Alkox. From the in vitro assessment of the adhesiveness of APNgels, the adhesiveness of APNgel increased with an increase in the amount of added Alkox. The release behavior of APN from APNgels was investigated by the paddle bead method, mimicking the chewing action in mouth. The APNgel was sheared by the beads and the release of APN completed within 480 s. From the results of the sensory test, APNgel consisting of 2.0% iota-CG and 1.0% Alkox seemed to be favorite to the jelly-like preparation.