Risk management and statistical multivariate analysis approach for design and optimization of satranidazole nanoparticles.

Rapidly evolving technical and regulatory landscapes of the pharmaceutical product development necessitates risk management with application of multivariate analysis using Process Analytical Technology (PAT) and Quality by Design (QbD). Poorly soluble, high dose drug, Satranidazole was optimally nanoprecipitated (SAT-NP) employing principles of Formulation by Design (FbD). The potential risk factors influencing the critical quality attributes (CQA) of SAT-NP were identified using Ishikawa diagram. Plackett-Burman screening design was adopted to screen the eight critical formulation and process parameters influencing the mean particle size, zeta potential and dissolution efficiency at 30min in pH7.4 dissolution medium. Pareto charts (individual and cumulative) revealed three most critical factors influencing CQA of SAT-NP viz. aqueous stabilizer (Polyvinyl alcohol), release modifier (Eudragit® S 100) and volume of aqueous phase. The levels of these three critical formulation attributes were optimized by FbD within established design space to minimize mean particle size, poly dispersity index, and maximize encapsulation efficiency of SAT-NP. Lenth's and Bayesian analysis along with mathematical modeling of results allowed identification and quantification of critical formulation attributes significantly active on the selected CQAs. The optimized SAT-NP exhibited mean particle size; 216nm, polydispersity index; 0.250, zeta potential; -3.75mV and encapsulation efficiency; 78.3%. The product was lyophilized using mannitol to form readily redispersible powder. X-ray diffraction analysis confirmed the conversion of crystalline SAT to amorphous form. In vitro release of SAT-NP in gradually pH changing media showed <20% release in pH1.2 and pH6.8 in 5h, while, complete release (>95%) in pH7.4 in next 3h, indicative of burst release after a lag time. This investigation demonstrated effective application of risk management and QbD tools in developing site-specific release SAT-NP by nanoprecipitation.

Mechanistic investigation of biopharmaceutic and pharmacokinetic characteristics of surface engineering of satranidazole nanocrystals.

The designing of surface engineered nanocrystals for improved stability and bioavailability is a multivariate process depending on several critical formulation and process variables. The present investigation deals with formulation of stable nanocrystals of poorly soluble satranidazole (SAT) for improving dissolution rate and pharmacokinetic profiling. SAT has low polar surface area, high dose and dosing frequency. Based on goniometric and stability studies of formulations prepared with various stabilizers, a unique combination of Span 20 and HPMC E-5 was selected for detailed investigation. Lyophilization of SAT nanosuspension was explored with nine different cryoprotectants in varying amounts to obtain easily redispersible nanocrystals (SAT-NC). The mean particle size and zeta potential of SAT-NC were found to be 208.8nm and -41.3mV respectively. DSC and XRPD confirmed the crystalline state of SAT. In vitro release studies of SAT-NC showed almost complete dissolution within 20min in water. Extravascular, one compartment pharmacokinetic modeling of in vivo plasma concentration versus time studies in male Wistar rats revealed twofold increase in Cmax, and AUC0-∞. Method of residuals was employed to calculate rate of absorption Ka and lag time. Nanosizing with appropriate stabilizers and programmed processing conditions successfully produced SAT-NC with improved pharmaceutic and pharmacokinetic characteristics.