Optimizing Torasemide Gastroretentive In Situ Gel: Integration Of Central Composite Design

Purpose

Torasemide is a diuretic used to treat heart failure, edema, liver and kidney diseases, and hypertension.However, its poor solubility and short half-life (3.5 h) necessitate frequent dosing. To overcome these limitations, this study aims to develop a gastroretentive in situ floating gel for Torasemide, utilizing raft-forming and in situ gel-forming systems to enhance gastric retention and sustain drug release for precise gastrointestinal delivery.

Methods

A Torasemide in situ gastric floating gel for sustained drug release was formulated to improve solubility through 2-hydroxypropyl-β-cyclodextrin (2-HPβCD) complexation and optimised using central composite design (CCD). Sodium Alginate (X1) and Gellan Gum (X2) were varied at five levels to evaluate the effects on viscosity (Y1) and floating lag time (Y2) as response variables. Design of Experiment (DoE) software guided the preparation of 13 formulations with varying concentrations of these independent variables.

Results

The optimised batch demonstrated a viscosity of 182.26 cps and a floating lag time of 81.36 s, achieving notably superior performance with 89.51% cumulative drug release over 12 h compared to 52.85% for pure Torasemide in the gelling base. The release profile aligned best with the Hixon-Crowell model. X-ray imaging verified 12-h gastric retention in the in vivo rabbit model, and stability studies confirmed that the formulation remained stable for over 3 months under accelerated conditions (40 ± 2 °C/75 ± 5% RH).

Conclusion

This innovative formulation holds promise as a therapeutic advancement. By forming the complex with 2-hydroxypropyl-β-cyclodextrin, the formulation significantly enhances Torasemide's solubility and bioavailability, enabling sustained drug release and thereby improving therapeutic efficacy in managing hypertension and related conditions.