Nanostructured liquid-crystalline particles for drug delivery

Liquid Crystal Systems in Drug Delivery

Liquid crystals have been recently studied as novel drug delivery system. The reason behind this is their similarity to colloidal systems in living organisms. They have proven to be advantageous over Traditional, Dermal, Parentral and Oral Dosage forms. Liquid crystals are thermodynamically stable and possess long shelf life. Liquid crystals show bio adhesive properties and sustained release effects. Objective of this book chapter is to provide in-depth information of Pharmaceutical crystal technology. It shall deal with cubic and hexagonal liquid crystal and their applications in Drug delivery system.

A novel paclitaxel-loaded poly(d,l-lactide-co-glycolide)-Tween 80 copolymer nanoparticle overcoming multidrug resistance for lung cancer treatment

Drug resistance has become a main obstacle for the effective treatment of lung cancer. To address this problem, a novel biocompatible nanoscale package, poly(d,l-lactide-co-glycolide)-Tween 80, was designed and synthesized to overcome paclitaxel (PTX) resistance in a PTX-resistant human lung cancer cell line. The poly(d,l-lactide-co-glycolide) (PLGA)-Tween 80 nanoparticles (NPs) could efficiently load PTX and release the drug gradually. There was an increased level of uptake of PLGA-Tween 80 in PTX-resistant lung cancer cell line A549/T, which achieved a significantly higher level of cytotoxicity than both PLGA NP formulation and Taxol^®. The in vivo antitumor efficacy also showed that PLGA-Tween 80 NP was more effective than Taxol^®, indicating that PLGA-Tween 80 copolymer was a promising carrier for PTX in resistant lung cancer.

Usefulness of liquid-crystal oral formulations to enhance the bioavailability and skin tissue targeting of p-amino benzoic acid as a model compound

Topical formulations are not always suitable to deliver active ingredients to large areas of skin. Thus, in this study, we aimed to develop an oral formulation for skin tissue targeting with a high bioavailability using liquid crystal (LC) dispersions comprising cubosomes of a mal-absorptive model compound, p-amino benzoic acid (PABA), which is an active element in cosmeceuticals, dietary supplements and skin disorder medicines. The bioavailability and skin concentration of PABA were investigated after oral administration in rats. The effect of the remaining amount of the LC formulation in the stomach on the pharmacokinetic profiles of orally administered PABA was evaluated. The skin permeation and concentration of PABA were also investigated using an in vitro permeation experiment. As a result, the bioavailability of PABA was significantly improved by administration of PABA-LC formulations compared with PABA solution alone, although the effect was greatly influenced by the type of LC-forming lipids. The in vitro skin permeation study showed that the PABA concentration in the skin when applied from the dermis side was higher than when applied from the epidermis side. These findings suggested that oral administration advantageously supports skin targeting, and oral LC formulations could be a promising material in cosmeceutical, dietary and clinical fields.

Functional nanoemulsion-hybrid lipid nanocarriers enhance the bioavailability and anti-cancer activity of lipophilic diferuloylmethane

The purpose of this study was to assess the enhanced physicochemical characteristics, in vitro release behavior, anti-lung cancer activity, gastrointestinal absorption, in vivo bioavailability and bioequivalence of functional nanoemulsion-hybrid lipid nanocarriers containing diferuloylmethane (DNHLNs). The DNHLNs were first fabricated by loading water-in-oil nanoemulsions into hybrid lipid nanosystems using nanoemulsion-thin film-sonication dispersion technologies. The in situ absorption and in vitro and in vivo kinetic features of DNHLNs were measured using an in situ unidirectional perfusion method, a dynamic dialysis method and a plasma concentration-time profile-based method, respectively. The cytotoxic effects of DNHLNs in lung adenocarcinoma A549 cells were examined using MTT colorimetric analysis. The absorptive constants and permeabilities of DNHLNs in four gastrointestinal sections increased by 1.43-3.23 times and by 3.10-7.76 times that of diferuloylmethane (DIF), respectively. The relative bioavailability of DNHLNs to free DIF was 855.02%. DNHLNs inhibited cancer cell growth in a time- and dose-dependent manner. DNHLNs markedly improved the absorption and bioavailability of DIF after oral administration. DNHLNs had stronger inhibitory effects on the viability of A549 cells than that of free DIF. DNHLNs might be potentially promising nanocarriers for DIF delivery via the oral route to address unmet clinical needs.

Cubosomes and hexosomes as versatile platforms for drug delivery

Nonlamellar liquid crystalline phases are attractive platforms for drug solubilization and targeted delivery. The attractiveness of this formulation principle is linked to the nanostructural versatility, compatiblity, digestiblity and bioadhesive properties of their lipid constituents, and the capability of solubilizing and sustaining the release of amphiphilic, hydrophobic and hydrophilic drugs. Nonlamellar liquid crystalline phases offer two distinct promising strategies in the development of drug delivery systems. These comprise formation of ISAsomes (internally self-assembled ‘somes’ or particles) such as cubosomes and hexosomes, and in situ formation of parenteral dosage forms with tunable nanostructures at the site of administration. This review outlines the unique features of cubosomes and hexosomes and their potential utilization as promising platforms for drug delivery.

Lyotropic La-containing lamellar liquid crystals: phase behaviour, thermal and structural properties

This paper provides the results of POM, DSC and XRPD methods characterizing the liquid crystalline behaviour, thermal properties and structural parameters of lyotropic systems based on a nonionic surfactant and lanthanum nitrate (La(3+)). The systems based on tetraethylene glycol monododecyl ether (C12EO4) and lanthanum nitrate have been demonstrated to form a lamellar phase. The concentration and temperature ranges of the existence of mesophases as well as thermodynamic parameters of phase transitions have been estimated. The structural parameters of the lamellar phase of the C12EO4/La(3+)/water systems have been determined using X-ray diffraction. The model of molecular packing in lamellar lanthanide-containing lyotropic mesophases was proposed for the observed patterns of structural parameters obtained at various water contents. NMR (1)H with a pulsed magnetic field gradient has been used to characterize molecular motions in the C12EO4/La(3+)/H2O systems with different water contents.

Cubic and hexagonal liquid crystals as drug delivery systems

Lipids have been widely used as main constituents in various drug delivery systems, such as liposomes, solid lipid nanoparticles, nanostructured lipid carriers, and lipid-based lyotropic liquid crystals. Among them, lipid-based lyotropic liquid crystals have highly ordered, thermodynamically stable internal nanostructure, thereby offering the potential as a sustained drug release matrix. The intricate nanostructures of the cubic phase and hexagonal phase have been shown to provide diffusion controlled release of active pharmaceutical ingredients with a wide range of molecular weights and polarities. In addition, the biodegradable and biocompatible nature of lipids demonstrates the minimum toxicity and thus they are used for various routes of administration. Therefore, the research on lipid-based lyotropic liquid crystalline phases has attracted a lot of attention in recent years. This review will provide an overview of the lipids used to prepare cubic phase and hexagonal phase at physiological temperature, as well as the influencing factors on the phase transition of liquid crystals. In particular, the most current research progresses on cubic and hexagonal phases as drug delivery systems will be discussed.