Rational and precise development of amorphous polymeric systems with dapsone by response surface methodology

This work aimed to design dapsone (DAP) amorphous Polymeric Dispersions (PD) using design of experiments (DoE) and response surface methodology (RSM) as optimization tools in order to tailor the biopharmaceutical properties toward its oral delivery. A two-factor, three-level (32) statistical design was implemented to study the influence of input variables (amount of PVP K30 and Pluronic F68) on the equilibrium solubility of DAP of the physical mixture (PM), kneaded (KN) and freeze dried (FD) PDs. Through the analysis, it was found that equilibrium solubility of DAP was improved with increasing of PVP K30, mainly for FD PDs, but decreased with increasing Pluronic F68 concentration. XRD and FTIR spectrum revealed the amorphous characteristic of FD PDs and SEM confirmed the homogeneity of the system leading to enhanced surface area and consequent dissolution rate. The in vitro dissolution rate of PDs was significantly faster compared to DAP and PM, and all the similarity factors (f2) were below 50, demonstrating the differences on the dissolution profiles. The results established the effectiveness of PDs for improvement of dissolution and solubility of DAP and the success in the implementation of DoE and RSM as QbD tools in the design of PDs.