Formulation and Evaluation of Floating Oral in situ Gel of Liquorice Extract

Abstract:

Background: The in situ gel, which after gelation floats in the stomach, is appropriate for sustaining drug release. Aqueous extract of liquorice used for the treatment of peptic ulcers and Helicobacter pylori, was used to create an in situ gel in the current research study for prolonged action. Materials and Methods: The aqueous extract of liquorice was subjected to phytochemical screening; pre-formulation studies such as extract compatibility with selected polymers. In situ gel containing liquorice extract, sodium alginate (Gelling Polymer), HPMC K100M (release retardant), Calcium Carbonate (Gas Generating Agent), Tri-Sodium Citrate and Methyl paraben were prepared by using pH induced ion gelation method and various parameters are evaluated. A factorial design was employed to evaluate the independent parameters i.e., sodium alginate and HPMC K100M, on dependent parameters such as lag time, viscosity and in vitro drug release at 9th hr of the formulation. Results: The pre-formulation studies showed compatibility between extract and excipient. The in situ formulation showed a pH ranges from 7.44 to 7.88, Viscosity 72.67 to 596.33 cps, lag time of 14.67 to 73 sec, Drug content 49.139 to 71.471% and remain buoyant in gastric environment for more than 12 hr. Concentration of HPMC K100M and Sodium Alginate decreases drug release due to the formation of rigid gel structure. Mechanism of drug release from formulations was Non Fickian super case-II, fitting into the Korsmeyer Peppas model. Conclusion: The optimized formulation was found to have a lag time of 28.67 sec, pH 7.69, viscosity 268 sec and drug release of 73.98% at end of 9th hr and found to be in acceptable range. Therefore, liquorice extract oral in situ solution can be a promising approach for prolonged and sustained effect for treating peptic ulcers.

Keywords: Liquorice extract, in situ gel, Peptic ulcer, Sustained release, Sodium Alginate, HPMC K100M, Gelling capacity, Floating ability.