Design, Optimization, and Evaluation of a Rutin–Glycyrrhiza Glabra In-Situ Floating Gel for Gastric Ulcer Management Using a QBD Approach

Abstract

The aim of this study was to develop and optimize an oral in-situ floating gel containing Rutin and Glycyrrhiza glabra (Liquorice) extract for the effective management of peptic ulcer disease. The Liquorice extract was obtained using the Soxhlet extraction method, while the solubility of Rutin was enhanced by preparing solid dispersions with hydroxypropyl methylcellulose (HPMC) as a carrier in varying concentration ratios (1:1, 1:2, 1:3, and 1:4). Among these, the 1:3 ratio exhibited the highest solubility enhancement, showing a six-fold increase in solubility and achieving 90% drug release. A 3² full factorial design based on Quality by Design (QbD) principles was employed to optimize the formulation. The independent formulation variables were the concentrations of gellan gum and calcium carbonate, while the dependent variables were floating lag time and viscosity. A total of nine formulations were prepared and evaluated for physicochemical characteristics, drug content, pH, floating behaviour, viscosity, and drug release profile. Among the formulations, Batch F9 was identified as the optimized formulation, demonstrating a floating lag time of 25 seconds, viscosity of 55.1 cp, drug release of 98%, drug content of 97%, pH of 7.1, and water uptake capacity of 89%. The optimized in-situ gel showed excellent floating properties and sustained drug release, indicating prolonged gastric residence and enhanced bioavailability. The findings suggest that the combination of Rutin and Liquorice extract in an optimized in-situ floating gel provides a stable gastro-retentive drug delivery system with significant potential for sustained localized therapy in the management of peptic ulcer disease. This formulation approach offers an effective strategy for improving the therapeutic efficacy and patient compliance in ulcer treatment.