This study aims to develop an on-site preparable jelly formulation in which a poorly soluble basic drug can be dissolved at a high concentration, by lowering the pH of the solution in the jelly. High methoxyl (HM)-pectin was used as a gel base and gelation was initiated by mixing with reduced maltose powder in water. The pH of the jelly was adjusted to about 2.5 by adding citric acid/trisodium citrate and phytic acid. As model drugs, dipyridamole (DIP, reagent or pulverized tablet) or ketoconazole (KTZ, reagent) was used. Low pH jelly formulations showed 5,000-6,000 Pa of breaking stress after 24 hours of preparation, which is adequate for elderly patients to swallow. In the dissolution study using a pH 6.8 medium, dissolution rates of both DIP and KTZ were much faster and higher (more than 80%) from the low pH jelly formulation than from the solid drug powder or tablet. The low pH jelly formulation induced a supersaturated dissolution of DIP and KTZ, which may improve their dissolution and absorption after oral administration, even in patients with high gastric pH. The hardness, pH and drug dissolution profiles were kept unchanged for 1 week after preparation.

In conclusion, this study successfully developed a simple method for on-site preparation of a low pH oral jelly formulation. The results obtained here are significant not only for the development of patient-friendly formulations for the elderly, but also for improving drug absorption in patients with impaired gastric acid secretion to ensure adequate drug efficacy.