preparation and comparison of various formulations of solid lipid nanoparticles (slns) containing essential oil of zataria multiflora

Purpose: the aim of this study was to formulate a new delivery system by the incorporation of zataria multiflora. essential oil into solid lipid nanoparticles (sln). research method: sln formulations were prepared following the highpressure homogenization after starring and ultratrax homogneization techniques. in this experiment, three slns formulations were prepared using three types of lipids. lipids included glycerol monostearate lipid, precirol and stearic acid lipid. the slns were characterized by differential scanning calorimetery (dsc), transmission electron microscopy (tem) and particle size analysis. findings: the results showed that particle size, polydispersity index and zeta potential of the above formulations were about 255, 220, 486 nm, 0.369, 0.251, 0.296,-37.8, -17.6, -27.2 mv respectively. the results obtained from transmission electron microscopy (tem) revealed that in all 3 formulations, particle size less than 200 nm were spherical. thermal analysis by dsc, confirmed the presence of solid particles in the prepared slns. also, the essential oil encapsulation percentage of formulations 1, 2 and 3 were 85.3, 91.3 and 95.2% respectively. stability studies of particle size and zeta in four months revealed that slns containing essential oils had relatively good stability. research limitations: limitations of slns are: lipid particle growth, unpredictable gelation tendency. originality/value: due to the chemical structures of essential oils, eos can be easily degraded after exposure to humidity, heat, oxygen, light, owing to chemical and enzymatic reactions. to overcome the drawbacks of eos, several researchers have suggested the encapsulation of these active ingredients into nanocarriers. the results of the present research revealed that slns composed of glycerin monostearate lipids, precirol and stearic acid, were good carriers for z. multiflora essential oil.