Optimization of Redispersible Spray Dried Powder of Chitosan Coated Solid Lipid-Based Nanosystems

Abstract

The present work describes the optimization of spray dried powder of solid lipid-based nanosystems to improve drug stability, surface modification and to obtain nanosystems after redispersion. Chitosan coated solid lipid nanoparticles containing bromocriptine mesylate (cBMSLN) were prepared by high pressure homogenization technique following by chitosan addition. For spray drying, response surface methodology with central composite rotatable design was to optimize 3 parameters: inlet temperature, pump rate and feed concentration. From regression analysis, powder yield, moisture content and size of redispersed nanoaggregates as responses were fitted well with linear, quadratic and quadratic equation models, respectively. Spherical powders with size of 4-5 µm and 70% yield were obtained at optimum parameters which were also used to prepare powder of chitosan coated nanostructured lipid carriers containing BM (cBMNLC). Amorphous characteristics were confirmed from powder XRD patterns and DSC chromatograms in all prepared powders. Redispersion of powders yielded nanosystems of some original nanosize and a greater portion of larger size. Smoother surface of NLC systems was observed, so was with chitosan coating. Drug entrapment was >85% but significantly decreased in chitosan coated formulations while drug retention after spray drying showed opposite results. After storage, spray dried powder could retain higher drug content than the original nanosystems. Obviously, NLC systems had better drug stability results than SLN systems. It could be concluded that redispersible spray dried powders of chitosan coated lipid-based nanosystems especially NLC systems were successfully obtained with surface modification, nanoaggregate size range and improved drug stability.Keywords: Solid lipid nanoparticles, nanostructure lipid carriers, chitosan, spray drying, optimization, redispersion, bromocriptine mesylate