Evaluating the production process of Solid lipid nanoparticles: The effect of process parameters on the physicochemical properties of pre and final emulsion

Solid lipid nanoparticles (SLN) are one of the appropriate delivery systems which attract enormous interest for encapsulating bioactive componds in recent years. One of the important physicochemical properties of SLNs is particle size that is influenced by formulation and production process parameters. Inappropriate conditions of the nanaocarrier production process in the pre and main emulsion steps cause unsuitable paricle size as well as unstable emulsion and gel formation. Therefore, in this research production process of SLN was investigated and optimized by hot homogenization method and with two lipids of Compritol and Precirol separately. Hence, homogenization time in preparation of pre emulsion and amplitude and time of ultrasonication in final emulsion production was studied to obtained the smallest particle size. In pre emulsion step, the smallest particle size for Compritol SLN (619±4 nm) and Precirol SLN (373±3 nm) obtained in 180 second mixing by ultra-turax in 16000 (rpm). In final emulsion, 40% amplitude and 3 minutes caused to attained smallest particle size in Compritol SLN (397±5 nm) and Precirol SLN (259±2 nm). Then polydispersity index (PDI), zeta potential and visual observation of nanocarriers with optimized particle size were examined. The results showed that Precirol SLN had higher zata potential (-12.3±0.6 mV) than Compritol SLN (-8.97±0.17mV) but PDI of two nanocarriers was not significantly different. Visual observation of both nanocarriers at the storage time showed no instability.