Objective: Aim of the present study was to formulate solid lipid nanoparticles (SLNs) and to determine their physicochemical parameters when stored at cold temperature in aqueous solution (D-SLNs) prior to biological application.Methods: SLNs were formulated though nanoprecipitation technique which comprised of stearic acid (lipid), poloxamer 188 and lecithin (surfactant). Physicochemical parameters were estimated though particle size analysis, polydispersity index, surface morphology analysis (Scanning electron microscopy and Transmission electron microscopy) and cytotoxicity studies followed by live-dead staining through acridine orange and ethidium bromide.Results: SLNs with spherical morphology were successfully fabricated as revealed though SEM and TEM investigations. Fabricated SLNs had the mean particle size ranging from 188 nm (SLNs) to 327 nm (D-SLNs). Zeta potential was found to be±14mV to±6mV and polydispersity index was 0.297±0.18 for SLNs without incubation and 0.538±0.07 for SLNs after incubation. No cytotoxicity was observed for SLNs.Conclusion: SEM and TEM investigations showed morphological variation in SLNs and D-SLNs. Dissimilarity in mean particle size, zeta potential and polydispersity index indicates the increase in size and aggregation of nanoparticles. No cytotoxic effects of SLNs were observed in normal cells, suggesting storage of nanoformulation in the aqueous state has no effect in context to cytotoxicity. Hence we conclude that prolonged storage of formulation at cold temperature causes the deterioration of polymeric formulation
