Formulation design and evaluation of nasal in situ gel as a novel vehicle for azelastine hydrochloride.

For locally acting intranasal drugs, an extended residence time in the nasal cavity is desirable and related to a prolonged effect. The aim of the present work was to design a nasal delivery system with improved mucoadhesive properties that could provide prolonged retention time for the treatment of allergic rhinitis. A 32 factorial design was used to investigate effect of amount of gellan gum and mucoadhesive polymer namely HPMC E4M as independent variable. Viscosity and mucoadhesive strength were taken as dependent variables. The formulations were tested for gelation study, viscosity study, gel strength, mucoadhesion study, shot weight study, drug content, histopathological evaluation, and stability study. Gelation was determined by physical appearance. Viscosity study of sol and gel formulations indicated that increase in polymer concentration increases the viscosity. Shot weight of the formulations was found to proportionally vary with the viscosity of formulations. Gel strength was found in the range of 22-55 sec. The mucoadhesive force in terms of detachment stress increased with increase in the concentration of HPMCE4M. Histopathological examination of sheep nasal mucosa with control and optimized formulation did not show any change in the nasal tissue. A stability study for optimized AZ5 formulation as per ICH guideline for 90 days showed no change in pH, drug content, and viscosity. The developed in situ gelling system for azelastine hydrochloride using gellan gum in combination with HPMC E4M with improved mucoadhesive properties that could provide prolonged retention time for the treatment of allergic rhinitis