Thermoreversible-mucoadhesive gel for nasal delivery of sumatriptan.

The purpose of the present study was to develop intranasal delivery systems of sumatriptan using thermoreversible polymer Pluronic F127 (PF127) and mucoadhesive polymer Carbopol 934P (C934P). Formulations were modulated so as to have gelation temperature below 34 degrees C to ensure gelation at physiological temperature after intranasal administration. Gelation temperature was determined by physical appearance as well as by rheological measurement. The gelation temperatures of the formulations decreased by addition of increasing concentrations of Carbopol (ie, from 29 degrees C for 18% PF127 to 23.9 degrees C for 18% PF127, 0.5% Carbopol). The mucoadhesive force in terms of detachment stress, determined using sheep nasal mucosal membrane, increased with increasing concentration of Carbopol. The results of in vitro drug permeation studies across sheep nasal mucosa indicate that effective permeation coefficient could be significantly increased by using in situ gelling formulation with Carbopol concentration 0.3% or greater. Finally, histopathological examination did not detect any damage during in vitro permeation studies. In conclusion, the PF127 gel formulation of sumatriptan with in situ gelling and mucoadhesive properties with increased permeation rate is promising for prolonging nasal residence time and thereby nasal absorption.