Chitosan-enhanced mucoadhesive delivery for local action: Salivary pharmacokinetic estimation

Background: Sore throat ache is a discomforting condition for patients during the disease course while eating, drinking or swallowing. However, improved topical concentration of locally acting drugs can address this issue. Objectives: The goal of the current research was to formulate and evaluate the single-dose salivary pharmacokinetics of a chitosan (CT)-based mucoadhesive delivery system containing tibezonium iodide and lignocaine (LIG). Methods: Mucoadhesive buccal gels were formulated using a homogenization technique and then subsequently characterized for physical, physicochemical and mucoadhesive properties. The ex vivo mucoadhesive studies were conducted on healthy New Zealand rabbits (aged 12-14 weeks and weight range in between 2.2-2.5 kg). Results: Solid-state characterization revealed the absence of any unusual peaks in the physical mixture of the FTIR and DSC, whereas the unchanged physical form of drugs was confirmed through PXRD analysis. Formulations containing sodium alginate (SA) demonstrated greater swelling (15.39% in F4) but could not sustain drug release for up to 3 h at the polymer concentrations studied. Contrarily, poor mucoadhesive strength (MS) and mucoadhesive flow time (FT) were associated in formulations containing SA. Homogenization of CT and HPMC gels, when mixed at respective concentrations of 1.5% and 2% w/v, demonstrated sustained drug release over time, along with improved MS and FT values of 16.34 g and 142.20 min, respectively. Better salivary concentrations (Cmax) for LIG (5.14 µg/mL) and TIB (4.82 µg/mL) were observed at 2 and 3 h, respectively. Conclusion: Our study demonstrated higher Cmax concentrations of the locally acting drugs with single-dose mucoadhesive delivery in healthy volunteers, designed for sore throat, as a single-dose alternative to their respective conventional lozenges.