Research Article Effective Lipid Nanocarriers Based on Linseed Oil for Delivery of Natural Polyphenolic Active Lucia Marina Cristina Coc , 1 Ioana Lacatusu , 1 Nicoleta Badea , 1 Marcela Elisabeta Barbinta-Patrascu , 2 and Aurelia Meghea 1 1 University Politehnica of Bucharest, Faculty of Applied Chemistry and Materials Science, Polizu Street No. 1, 011061 Bucharest, Romania 2 University of Bucharest, Faculty of Physics, Department of Electricity, Solid-State Physics and Biophysics, 405 Atomistilor Street 077125, Bucharest-Magurele, Romania Correspondence should be addressed to Aurelia Meghea; a.meghea@gmail.com Received 18 September 2020; Revised 29 December 2020; Accepted 25 January 2021; Published 9 February 2021 Academic Editor: Antonio Vassallo Copyright © 2021 Lucia Marina Cristina Coc et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The main purpose of the present research was to test the ability of nanostructured lipid carriers (NLCs) to efficiently host a hydrophilic polyphenol active with health-promoting activities (caffeic acid (CA)). The caffeic acid-loaded lipid nanocarriers (CA-NLCs) were obtained by high-pressure homogenization technique using a surfactant mixture of Tween 20 and L-α- phosphatidylcholine in association with a lipid mixture of linseed oil, hexadecyl palmitate, and glycerol monostearate. In the first stage, the proportion between surfactant mixture and lipid phase has been varied to obtain appropriate stable nanocarriers. The optimized NLCs have been further loaded with different amounts of caffeic acid and were analyzed in terms of physical stability, size characteristics, and encapsulation efficiency. The antioxidant activity of CA-loaded NLCs and their release behavior have been tested by specific in vitro methods, e.g., ABTS (2,2-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid)) assay and release experiments, by Franz cell diffusion. The ABTS assay highlighted a high antioxidant potential of the caffeic acid in association with linseed oil. The capacity to capture ABTS cationic radicals was superior for the NLC entrapping an initial amount of 1.5% CA, the level of antioxidant capacity being 91.3%. The in vitro release experiments showed a different release behavior, depending on the initial amount of caffeic acid used. NLC loaded with a higher concentration of CA manifests a gradual slow release, e.g., 45% CA after 24 h of in vitro experiments, while the NLC loaded with smaller concentration of CA assured a higher release in time, around 65%. 1. Introduction During the past decade, lipid nanoparticles have been inves- tigated as platforms for efficient drug encapsulation and sus- tained release at the specific site of many localized diseases. The solid lipid nanoparticles (SLNs) and nanostructured lipid carriers (NLCs), respectively, are derived from oil/water emulsions, with the remark that the solid lipids or a mixture of solid and liquid lipids, respectively, replace the liquid lipids [1]. Lipid nanoparticles have an average diameter ranging between 50 and 1000 nm, a spherical morphology containing a solid lipid core surrounded by a surfactant shell. One of the most important features of the lipid matrix is its ability to maintain in solid form at both ambient and body tempera- tures [2]. NLCs are known as improved systems of SLNs, showing a better stability and higher encapsulation efficiency for numerous active compounds. Concomitantly, the NLCs prevent the active substances’ expulsion from the lipid matrix during storage, thus increasing their stability and efficacy during administration [3]. NLCs are considered modified SLNs in which the lipidic phase contains both solid and liquid lipids at ambient tem- perature, which generate imperfections within the matrix, decreasing its crystallinity and facilitating the accommoda- tion of drug molecules [4, 5]. In this sense, improved drug encapsulation, minimized drug leakage during storage, and Hindawi Journal of Nanomaterials Volume 2021, Article ID 8853941, 9 pages https://doi.org/10.1155/2021/8853941