Effect of lipid chain length on nanostructured lipid carriers: Comprehensive structural evaluation by scattering techniques

The objective of the present investigation was to evaluate nano-dispersed systems of differently chained lipids (solid phases) using various scattering techniques. Nanostructured lipid carriers (NLCs) were fabricated by employing the microemulsification methodology in which dialkyldimethyl ammonium bromide (D(x)DAB) of different alkyl chain length (x = 12, 14, 16, 18) and oleic acid were used as the solid lipid and liquid lipid, respectively. For the first time, the effect of D(x)DAB as a function of the chain length of the double alkyl chain on the structural characteristics of NLCs was investigated. Dynamic light scattering (DLS) and static light scattering (SLS) results showed that a small but systematic size increase occurs with increase in the chain length of the D(x)DAB from 12 to 16, yet D(18)DAB based NLCs exhibited the smallest size irrespective of its higher hydrophobicity. Small angle neutron scattering (SANS) analysis revealed the structural make up of NLCs having spherical nanoparticles and triaxial ellipsoidal core-shell micelles in the system. In-vitro cytotoxicity evaluation indicated that toxicity is simply concentration dependent phenomena and NLCs with less than 5 mg/mL are preferred for better in-vivo tolerance. (C) 2018 Elsevier Inc. All rights reserved.