FORMULATION AND IN-VITRO EVALUATION OF POLYETHYLENE GLYCOL BASED ORAL MUCOADHESIVE GELS OF TACROLIMUS MONOHYDRATE

Oral Lichen Planus (OLP) is a rare chronic autoimmune mucocutaneous inflammatory disease characterized by painful oral lessions. Immunosuppressive agent Tacrolimus monohydrate is one of the effective therapy options for OLP as it possesses benefits such as greater safety and efficacy at lower doses over currently employed topical corticosteroids. From amongst its topical dosage forms, mucoadhesive oral gels of Tacrolimus monohydrate have advantages such as prolonged residence time, enhancement of absorption and therapeutic efficacy compared to the topical ointments. Considering this, the current work was aimed at formulating oral mucoadhesive gels of Tacrolimus monohydrate using PEG gel bases and mucoadhesive polymers. Firstly, non medicated mucoadhesive gels consisting of PEG gel bases and mucoadhesive polymers were formulated and evaluated for their appearance, feel, viscosity, pH, spreadability, tube extrudability and mucoadhesive strength. The combinations of PEG gel bases having PEG4000+PEG400 in 1:4, PEG 4000+PEG400 in 1:8 and PEG 6000+PEG400 in 1:4 were selected for incorporation of Tacroliimus monohydrate (0.1%) due to their ideal performance in maintaining the requisite gel characteristics at 40⁰C and 75% RH after incorporation of the mucoadhesive polymers. These medicated gels were then compared to commercially available smile gel as a reference for viscosity, spreadability, tube extrudability and mucoadhesive strength. It was observed that the medicated gel consisting of Tacroliimus monohydrate (0.1%) incorporated to PEG gel bases (PEG4000+PEG400 in 1:4) having Gantrez S-97 as mucoadhesive polymer exhibited maximum drug release and drug content. This gel batch showed prolonged and better in-vitro release compared to the marketed protopic ointment.