Aqueous colloidal drug carrier dispersions based on nonpolar lipids are usually prepared by high energy dispersion techniques, like high-pressure homogenization. Homogenization generates high shear forces and may thus not be suitable for the processing of sensitive pharmaceutical ingredients, e.g., proteins. This study investigated the general possibility to prepare lipid nanoparticle dispersions by direct and premix Shirasu Porous Glass (SPG) membrane emulsification as alternative low energy and low shear method. The influence of different emulsifiers (polysorbate 20, sorbitan oleate, poloxamer 188, sodium dodecyl sulfate, sucrose laurate), the type of lipid phase (medium chain triglycerides, soybean oil, trimyristin, glyceryl behenate, lauroyl macrogolglycerides), the pore size of the SPG membrane (0.1, 0.2, 0.3, 0.5, 1.1μm) and the emulsifying pressure on the particle size of the resulting dispersions was investigated. The particle size was primarily controlled by the pore size of the membrane and the emulsifying pressure. Very narrow particle size distributions with membrane pore size/mean particle size ratios of 1:0.4-1:8.2 and 1:0.4-1:2.1 were observed for the direct and the premix membrane emulsification method, respectively. Due to the comparatively lower process pressures of at maximum 10bar SPG membrane emulsification is an interesting alternative method to high-pressure homogenization.
Keywords: Colloidal lipid dispersions; Direct membrane emulsification; Nanoemulsions; Premix membrane emulsification; SPG (Shirasu Porous Glass) membranes; Solid lipid nanoparticles.
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