DESIGN, CHARACTERIZATION AND EVALUATION OF MUCOADHESIVE NASAL IN SITU GELLING FORMULATIONS OF VENLAFAXINE HYDROCHLORIDE FOR BRAIN TARGETTING

The poor bioavailability and the therapeutic effectiveness exhibited by the anti-depressant venlafaxine hydrochloride on oral administration is overcome by the use of ion-activated gel forming systems that are instilled as drops; these undergo gelation in the nasal cavity. The present study describes the design, characterization and evaluation of mucoadhesive nasal in situ gelling drug delivery of venlafaxine hydrochloride using different polymers like sodium alginate, HPMC and pectin in various concentrations. DSC studies revealed compatibility of the drug and excipients used. The in situ gels were characterized for physicochemical parameters, gelling ability, rheological studies, drug content, drug entrapment efficiency, in vitro mucoadhesive strength, water holding capacity, gel expansion coefficient and in vitro drug release studies. The amount of polymer blends was optimized using 23 full factorial design. The influence of experimental factors on percentage cumulative drug release at the end of 2 and 8 hours were investigated to get optimized formulation. The responses were analyzed using ANOVA and polynomial equation was generated for each response using multiple linear regression analysis. Optimized formulation, F9, containing 1.98% w/V sodium alginate, 0.64% w/V hydroxylpropyl methylcellulose, 0.99% w/V pectin showed percentage cumulative drug release of 19.33 and 80.44 at the end of 2 and 8 hours, respectively, which were close to the predicted values. The optimized formulation was subjected to stability study for three months at 300C /75% RH. The stability study revealed no significant change in pH, drug content and viscosity. Thus, venlafaxine hydrochloride nasal mucoadhesive in situ gel could be successfully formulated to improve bioavailability and to target the brain.