Tabriz University of Medical Sciences Medical Journal of Tabriz University of Medical Sciences 2783-2031 36 6 2015 02 05 Formulation and Optimization of Controlled Release of Olanzapine by Glycerol Monooleate 14 21 EN Gita Bagheri Farid Abedin Dorkoosh Ebrahim Vasheghani-Farahani Mehdi Ardjmand Hossein Attar Journal Article 2013 12 07 2014 01 21 Background and Objectives: In situ gel formation of Glycerol Monooleate (GMO) has been utilized to release many drugs. The aim of this research was to optimize, and in-vitro characterization of the controlled release and formulation of the matrices containing Olanzapine (OZ), GMO and Polyethylene glycol (PEG 300). Methods and Materials: Response surface methodology (RSM) is a combination of mathematical and statistical techniques. In this study, Design-Expert® software with Box-Behnken response surface methodology has been used to determine the relationships between variables and responses. GMO/water weight ratio (w/w) different and PEG 300/GMO (w/w) were in the range of 2-4% and 2-6% respectively. Percentage of loading; and release at 12th and 168th hr were calculated. In-vitro release studies of OZ from prepared gels were conducted in PBS (pH 6.8) and then analyzed by spectrophotometer at 265 nm. Results: The optimum formulation was obtained at weight ratio of water/GMO (w/w) and PEG (300)/GMO (w/w) at 0.28 and 0.2 respectively, and percentage of OZ was at 4%. The observed and predicted values for EE % were 86.8 %, 90.31% respectively those parameters for release at 12th hr were 16.1% and 15% and for release at 168th hr, were 59.8 % and 63.56% respectively. Conclusion: In this study we performed kinetic release profile of OZ with several models, from which Higuchi model showed the best fitting and correlation.