In vitro, ex vivo and in vivo performance of chitosan-based spray-dried nasal mucoadhesive microspheres of diltiazem hydrochloride

Present investigation deals with design, development and evaluation of chitosan-based spray-dried nasal mucoadhesive microspheres loaded with diltiazem hydrochloride (DTZ HCl). The principal objectives were to improve therapeutic efficacy through increased residence of microspheres on the nasal mucosa, and avoidance of hepatic first-pass metabolism. Formulation samples were characterized for preliminary physico-chemical parameters, mucoadhesiveness, drug release and release kinetics, mucosal toxicity, stability, and in vivo studies. Central composite experimental design was utilized herein to evaluate the influence of process and formulation variables product performance. Numerical and graphical optimization techniques were used for selecting optimum sample of prepared microspheres, further confirmed by three dimensional response surface plots and multilinear regression model. Results of ANOVA validated the significance of suggested models. Our findings suggest that DTZ-loaded spray-dried chitosan microspheres formulation could be used as a promising approach for intranasal administration which, in sum, improves therapeutic efficacy of the formulation. (C) 2015 Elsevier B.V. All rights reserved.