Rheological characterization, In vitro release, and Ex vivo permeation of Nefopam Thermosensitive and mucoadhesive intranasal in situ gel

Abstract

Nefopam nasal thermosensitive in situ gel based on poloxamer 407 and poloxamer 188 were formulated. The formulations that showed acceptable gelation temperature were selected for further evaluations; rheological, in vitro-release, and permeation behavior. Rheological studies show significant increase in viscosity when solution formed gel at gelation temperature and follow pseudoplastic flow, and as viscosity increased, slower erosion and drug release occurred. Drug release profiles were fitted to mathematical models (First-order, Zero order, Higuchi, Power law, and Peppas-Sahlin) using a DDSolver Excel Microsoft Add-in, dissolution profile comparison in addition to pairwise similarity factor (f2) was used for comparison between formulas dissolution. The flux and effective permeability coefficient parameters at steady state were calculated for selected formulas and compared with permeation of 20mg/ml Nefopam aqueous solution as control.