Sublingual Fast-Dissolving Thin Films of Loratadine: Characterization, In Vitro and Ex Vivo Evaluation

Loratadine (LOR) is a second-generation antihistamine that exhibits a low and variable oral bioavailability (10-40%) and delayed onset owing to poor solubility and an extensive first-pass effect. Therefore, in light of the clinical need, the main goal of the present study was to develop sublingual fast-dissolving thin films of LOR-citric acid co-amorphous systems (LOR-CAs) with the aim of eliciting a faster onset and improving the bioavailability. We formulated sublingual fast-dissolving thin films of LOR by a film-casting technique using hydrophilic polymers like hydroxypropyl methylcellulose (HPMC E15), polyvinyl pyrrolidone K30 (PVP K30), and hydroxypropyl cellulose EL (HPC-EF) and citric acid as a pH modulator, while glycerin served as a plasticizer. The sublingual fast-dissolving thin films were characterized by FTIR, SEM, DSC, and XRD and evaluated for in vitro dissolution and ex vivo mucoadhesion. The best formulation (F1) developed using HPMC E15 as a polymer, glycerin as a plasticizer, and citric acid as a pH modulator was found to be the optimized formulation as it was smooth, clear, flexible, and displayed good mucoadhesion (11.27 ± 0.418 gm/cm