Objective: Chitosan (CS)–tri polyphosphate (TPP)–nano particles (NPs) have been extensively studied during the past few decades due to their well-recognized applicability in various fields. Thus, the present study was aimed to optimise the fabrication conditions for the preparation of CS-TPP-NPs aiming towards smallest possible size, optimal zeta potential and narrow poly dispersity index (PDI), simultaneously.Methods: CS-TPP-NPs were prepared via ionic cross-linking of CS and TPP and were characterized physico-chemically (particle size, zeta potential and PDI) and morphologically. The influence of several formulation conditions (CS concentrations, CS: TPP mass ratio and initial pH of CS solutions) and process parameters (stirring speed, stirring time, ultra-sonication and ultra-centrifugation) on the colloidal characteristics of CS-TPP-NPs were investigated. In addition, the colloidal stability of the prepared NPs was also assessed on storage.Results: Results clearly identified that the formulation and process parameters showed significant impact on the physico-chemical and morphological characteristics of the CS-TPP-NPs. The CS-TPP-NPs prepared under optimum conditions (CS concentration of 0.2 mg/ml, CS: TPP mass ratio of 7:1, initial pH of CS solution of 4.0, stirred at 700 rpm for 10 min and ultra-centrifuged at 25 000 rpm for 30 min) had shown a mean particle size of ~187±21 nm, zeta potential of+37±3.5 mV, PDI of ~0.28±0.0390 as well as the smooth and round shaped morphology.Conclusion: The present study describes the optimal circumstances to fabricate the CS-TPP-NPs with finest physico-chemical characteristics and also explore the prospects of manipulation and optimisation of the NPs for intended applications.Keywords: Chitosan nanoparticles, Ionic cross-linking, Morphology, Ultra-sonication, Ultra-centrifugation, Colloidal stabilit
