Liposomes coated with hydrophobically modified hydroxyethyl cellulose: Influence of hydrophobic chain length and degree of modification

Abstract

Nanoparticulate systems with an uncharged hydrophilic surface may have a great potential in mucosal drug delivery. In the present study liposomes were coated with hydrophobically modified hydroxyethyl cellulose (HM-HEC) to create a sterically stabilized liposomal system with an uncharged surface. The aim was to clarify the influence of the amount of hydrophobic modification of HEC and the length of the hydrophobic moiety, on the stability of the system and on the release properties. HM-HEC with different degrees of hydrophobic modification (1 and 2 mole%) and hydrophobic groups with different chain lengths (C8, C12, C16) were included in the study, as well as fluid phase and gel phase liposomes. Both types of liposomes were successfully coated with HM-HEC containing 1 mole% of hydrophobic groups, while 2 mole% did not work for the intended pharmaceutical applications. The polymer coated gel phase liposomes were stable (size, zeta potential, leakage) for 24 weeks at 4 °C, with no differences between the C8 and C16 HM-HEC coating. For the fluid phase liposomes a size increase was observed after 24 weeks at 4 °C for all formulations; the C8 HM-HEC coated liposomes increased the most. No differences in the leakage during storage at 4 °C or in the release at 35 °C, were observed between the fluid phase formulations. To conclude; HM-HEC with a shorter hydrophobic chain length resulted in a less stable product for the fluid phase liposomes, while no influence of the chain length was observed for the gel phase liposomes (1 mole% HM).

Molecular Mechanism of Polycation-Induced Pore Formation in Biomembranes

“…Understanding the interaction of various polycations with lipid membranes is crucial for designing novel polycations with improved physicochemical properties and safety, and it is tailored to the specific application. − Polycations exhibit wide range of interactions with zwitterionic membranes that are used as models for mammalian cellular membranes; adsorption on the bilayer surface, insertion into the hydrophobic bilayer core, pore formation, , and disruption of the bilayer into mixed polymer–lipid micelles or other aggregates. , Such polycation–membrane interactions are primarily determined by the polycation architecture and its concentration. It has been shown that the presence of hydrophobic side chains in the structure of polycations plays an important role in the polymer–membrane interactions. − In our previous work, we addressed the effect of hydrophobic substitution of strong polycations on the polymer–zwitterionic membrane interactions, and especially the possibility of pore formation in lipid bilayers . However, the molecular mechanism of interaction between polycations and lipid membranes remains poorly understood, and in particular, the free-energy landscape of transmembrane pore formation remains unknown.…”

Jabuticaba (Myrciaria jaboticaba) Peel as a Sustainable Source of Anthocyanins and Ellagitannins Delivered by Phospholipid Vesicles for Alleviating Oxidative Stress in Human Keratinocytes

“…The latter interact with the bilayer in the internal and/or external surface, favoring sterically stabilized vesicles in dispersion [14][15][16]. Hydrophobically modified hydroxyethyl cellulose was previously used to coat liposomes, improving their stability [17]. Hydroxyethyl cellulose is a water-soluble polysaccharide derivative widely used in topical formulations.…”

Silk Fibroin-Coated Liposomes as Biomimetic Nanocarrier for Long-Term Release Delivery System in Cancer Therapy

“…To improve functionality of liposomes, the liposomal surface can be modified by conjugation with various moieties to extend blood circulation time and decrease the adsorption of blood proteins. In particular, liposomes can be coated with a biological matrix such as alginate, chitosan, pectin, collagen, or fibroin [ 8 , 9 , 10 , 11 , 12 , 13 , 14 ] to mimic the structure of biological cells due to the biocompatibility, biodegradability, and bioavailability of these biomaterials [ 15 ]. Moreover, these polymeric materials provide steric hindrance to prevent the aggregation of liposomes and inhibit the absorption of plasma proteins and RES uptake.…”