Mass Transfer of Olanzapine in the Liquid Lamellar Phases Formed by the Self-assembly of Glycerol Monooleate (GMO): Experimental Data and Mathematical Modeling

Aim: The present study aimed to optimise the formulation of Olanzapine (OZ)-loaded liquid lamellar phase by using Response Surface Methodology (RSM). Background: In this study, poly (2-ethyl-2-oxazoline) (PEOZ) was selected to modify liquid lamellar phases. The OZ was released from the phases mainly through swelling and diffusion-controlled mechanism simultaneously. Objective: Additionally, two types of mathematical models, based on the lumped and diffusion approaches, were presented for the diffusional release of OZ from the liquid lamellar phases, the second of which was solved with an analytical solution. The controlled release profiles of the models were compared with the in vitro experimental release profiles. Methods: Further, the Box-Behnken experimental design was employed to design the liquid lamellar phase with the three factors, including the weight ratio of water/GMO (w/w) (X1) and PEOZ/GMO (w/w) (X2), and the percentage of OZ (X3). The liquid lamellar phases were prepared based on the top-down method, followed by fragmentation by sonication. Furthermore, the diffusion coefficients of the liquid lamellar phases were calculated, and the effects of variables were evaluated on particle size and diffusion coefficient, as well as the constant of the lumped model. Results: The results revealed an increase in particle size following an enhancement in water level in the liquid lamellar phases, as well as less aggregation with the addition of PEOZ. Conclusion: The generated model was validated by comparing the experimental data and predicted model values graphically, the results of which represented compatibility between the lumped model and experimental data.