On the Structure of Solid Lipid Nanoparticles

Abstract

Solid lipid nanoparticles (SLNs) have a crystalline lipid core which is stabilized by interfacial surfactants. SLNs are considered favorable candidates for drug delivery vehicles since their ability to store and release organic molecules can be tailored through the identity of the lipids and surfactants used. When stored, polymorphic transitions in the core of drug‐loaded SLNs lead to the premature release of drug molecules. Significant experimental studies have been conducted with the aim of investigating the physicochemical properties of SLNs, however, no molecular scale investigations have been reported on the behaviors that drive SLN formation and their polymorphic transitions. A combination of small angle neutron scattering and all‐atom molecular dynamics simulations is therefore used to yield a detailed atomistic description of the internal structure of an SLN comprising triglyceride, tripalmitin, and the nonionic surfactant, Brij O10 (C18:1E10). The molecular scale mechanisms by which the surfactants stabilize the crystalline structure of the SLN lipid core are uncovered. By comparing these results to simulated liquid and solid aggregates of tripalmitin lipids, how the morphology of the lipids vary between these systems is demonstrated providing further insight into the mechanisms that control drug encapsulation and release from SLNs.

Time‐Resolved Fluorescence Anisotropy of a Molecular Rotor Resolves Microscopic Viscosity Parameters in Complex Environments

“…The Ligand Reader and Modeler on CHARMM‐GUI [ 34,41 ] was used to create the molecular model of triolein and cholesterol ester, which were then parameterized with the CHARMM General Force Field (CGenFF), [ 42–44 ] as was done previously for tripalmitin. [ 45 ] Finally, the interactions of BODIPY‐C12 was described by the same forcefield parameters as were used previously. [ 6 ] The Verlet cut‐off scheme was employed to generate the pair lists and the electrostatic interactions were calculated using the Particle‐Mesh Ewald algorithm.…”

Solid Lipid Nanoparticles for Drug Delivery: Pharmacological and Biopharmaceutical Aspects

“…Nowadays, however, it is known that this is not necessarily true in all cases, since disc-like shape or flat ellipsoidal geometry have also been described (Mazuryk et al, 2016;Shah et al, 2019). Moreover, the loaded drug may be attached mostly to the carrier matrix surface instead of being embedded into the solid core (Pink et al, 2019;Shah et al, 2019).…”

“…The oils in NLC act by reducing the crystalline degree of the lipid core of SLN, thus avoiding the expulsion of the drug from the matrix and increasing the drug loading capacity and physical and chemical long-term stability (Müller et al, 2002). The highlyordered crystalline structure of the lipids in a SLN has been recently studied by Pink et al (2019) whose work provides a detailed description of the internal and external structure of SLN.…”

Experimental Study on the Resistance of Synthetic Penicillin Solid Lipid Nanoparticles to Clinically Resistant Staphylococcus aureus

“…A silver complex of clotrimazole was synthesized, characterized, and further encapsulated into solid lipid nanoparticles to evaluate its antibacterial activity against SA and MRSA [ 21 , 22 ]. When firstly developed, SLN were presented as tiny and spherical particles, made of solid lipids at room temperature that may be thought as perfect crystal lipid matrices, able to accommodate a drug or other molecules between fatty acid chains [ 23 ]. SLN has stable properties and simple preparation.…”