Screening of ionically crosslinked chitosan-tripolyphosphate microspheres using Plackett–Burman factorial design for the treatment of intrapocket infections

Abstract

Objective: Application of Plackett–Burman factorial design to investigate the effect of processing factors in the fabrication of ionically crosslinked chitosan-tripolyphosphate (CS-TPP) microspheres. Significance: Microspheres were screened and optimized to provide maximum process yield (PY), encapsulation efficiency (EE), and time for 80% drug release (T80%) and minimum burst and particles size (PS), for successful application in periodontitis. Methods: Processing factors viz. method of preparation (MOP), CS, TPP, crosslinking time (CT), agitation (AS), and drying technique (DT) were selected. Solid state characterization was performed by Fourier-Transform infrared (FTIR), differential scanning calorimetry (DSC), X-ray diffraction (XRD), and scanning electron microscopy (SEM). Mucoadhesion, cytocompatibility, and stability of microspheres were also evaluated. Results: Pareto analysis and analysis of variance, screened most significantly (p <.05) impacting process factors on selected responses. The optimized microspheres demonstrated: o/w emulsification method, CS (2.5%), TPP (5%), CT (120 min), AS (2000 rpm), and DT (freeze-dried), and provided PY- 95.67%, PS- 168.45%, EEOZ- 85.56%, EEDX- 91.34%, BOZ- 15.26%, BDX- 12.91%, TOZ- 47.09 and TDX- 67.95 minutes. FTIR illustrated compatibility between excipients and complexation of CS and TPP. XRD and DSC showed loss of crystallinity of entrapped drugs in microspheres. Biphasic drug release was observed for four days with non-Fickian kinetics. Furthermore, microspheres exhibited good mucoadhesivity (82.51%), antimicrobial activity against Staphylococcus aureus and Escherichia coli, cytocompatibility for L929 cells, and long-term stability. Conclusions: Therefore, CS-TPP microspheres were found mucoadhesive, safe, stable and provided controlled and prolonged release of drugs. These properties confirmed its high potential and applicability in chronic periodontitis. © 2017 Informa UK Limited, trading as Taylor & Francis Group.