Thermosensitive mucoadhesive in situ gel for intranasal delivery of Almotriptan malate: Formulation, characterization, and evaluation

The present investigation deals with development, characterization, and evaluation of thermosensitive in-situ nasal gel of Almotriptan malate (selective serotonin 5-HT1 receptor agonist), serving as a substitute for drug delivery to the brain. Gels were prepared by cold technique varying the concentration of Pluronics (PF127 and PF68) and carboxymethyl chitosan as thermoreversible and mucoadhesive polymers respectively. Drug content before and after gelation was ranged between 96.42-98.92% and 95.8-98.66% respectively. The pH value was observed in the range of 5.56-6.31. Notably, the results obtained were in agreement with the phase transition and formulations exhibited pseudoplastic rheology. Mucoadhesive strengths of all the formulations increased with the chitosan concentration and were in the range of 3300-5193.65 dyn/cm(2). The in-vitro drug diffusion data of the optimized formulation i.e. 17% w/v PF127, 2% w/v PF68, 0.1% w/v carboxymethyl chitosan, revealed 89.36% release at the end of 6 h. Histopathological studies confirmed the non-toxic effect of optimized formulation on the microscopic structure of nasal mucosa during ex-vivo permeation studies. Short term stability study exhibited 4 +/- 1 degrees C as an appropriate storage condition for the formulations. In nutshell, a thermosensitive in-situ gel of Almotriptan malate can be intended as an effective approach of migraine treatment.