Characterisation of a novel solid lipid nanoparticle carrier system based on binary mixtures of liquid and solid lipids

A drug carrier of colloidal lipid particles with improved payloads and enha nced storage stability was investigated. Based on the experiences with hard fats nanoparticles, a new type of solid lipid nanoparticles (SLN) has been developed by incorporating triglyceride containing oils in the solid core of said particle. The structure and mixing behaviour of these particles wer e characterised and practical implications on controlled release properties tested. Nanoparticles were characterised by their melting and recrystallis ation behaviour as recorded by differential scanning calorimetry (DSC). Pol ymorphic form and bilayer arrangement were assigned by wide-angle X-ray sca ttering (WAXS) and small-angle X-ray scattering (SAXS). Size distribution a nd storage stability were investigated by laser diffractometry (LD). Releas e properties were studied by drug release model according to Franz. A mediu m chain triglyceride oil was incorporated successfully in a matrix of a sol id long chain glyceride. The crystal order was greatly disturbed, however, the carrier remained solid. The oil inside the particle remained in a liqui d state and induced a slight shift form the beta' polymorph to the beta(i) form. Long spacings varied within 0.1 nm with increasing oil loads. Nanopar ticles with low oil concentrations showed sustained release properties. Imp roved drug load levels were encapsulated by lipid particles supplemented wi th oily constituents. Thus, the presented carrier adds additional benefits to the well-known opportunities of conventional SLN and is suited for topic al use. (C) 2000 Published by Elsevier Science B.V. All rights reserved.