CO2/water/surfactant ternary systems and liposome formation using supercritical CO2: A review

Current Applications of Liposomes for the Delivery of Vitamins: A Systematic Review

Liposomes have been used for several decades for the encapsulation of drugs and bioactives in cosmetics and cosmeceuticals. On the other hand, the use of these phospholipid vesicles in food applications is more recent and is increasing significantly in the last ten years. Although in different stages of technological maturity-in the case of cosmetics, many products are on the market-processes to obtain liposomes suitable for the encapsulation and delivery of bioactives are highly expensive, especially those aiming at scaling up. Among the bioactives proposed for cosmetics and food applications, vitamins are the most frequently used. Despite the differences between the administration routes (oral for food and mainly dermal for cosmetics), some challenges are very similar (e.g., stability, bioactive load, average size, increase in drug bioaccessibility and bioavailability). In the present work, a systematic review of the technological advancements in the nanoencapsulation of vitamins using liposomes and related processes was performed; challenges and future perspectives were also discussed in order to underline the advantages of these drug-loaded biocompatible nanocarriers for cosmetics and food applications.

Use of supercritical CO2 for the sterilization of liposomes: Study of the influence of sterilization conditions on the chemical and physical stability of phospholipids and liposomes

The effects of four potential supercritical carbon dioxide (ScCO₂) sterilization conditions on the chemical stability of 9 phospholipids and on the physicochemical characteristics of liposomes consisting of stable phospholipids, as well as their sterilization efficiency were evaluated. These conditions were : C1 (ScCO₂/70 °C/150 bar/240 min), C2 (ScCO₂/0.25 % water/ 0.15% H₂O₂/ 0.5% acetic anhydride/38° C/85 bar/45 min), C3 (ScCO₂/0.08 % peracetic acid/35° C/104 bar/180 min) and C4 (ScCO₂/200 ppm H₂O₂/40 °C/270 bar/90 min). The results showed for phospholipids, a significant increase in hydrolysis products of 3.77 to 14.50 % and an increase in oxidation index of 6.10 to 430.50 % with unsaturated phospholipids for all tested conditions while with saturated phospholipids, no significant degradation was observed. Concerning the liposome formulation, no change in dispersion color and no phospholipid degradation were observed. However, a decrease in liposome size from 126.90 nm to 111.80 nm, 96.27 nm, 99.60 nm and 109.13 nm and an increase in the PdI from 0.208 to 0.271, 0.233, 0.285, and 0.298 were found with conditions C1, C2, C3 and C4 respectively. For the sterilization efficiency, conditions C1, C2 and C3 achieved the required sterility assurance level (SAL) of 10^-6 for liposomes.

Encapsulation of Vitamins Using Nanoliposome: Recent Advances and Perspectives

Nowadays the importance of vitamins is clear for everyone. However, many patients are suffering from insufficient intake of vitamins. Incomplete intake of different vitamins from food sources due to their destruction during food processing or decrease in their bioavailability when mixing with other food materials, are factors resulting in vitamin deficiency in the body. Therefore, various lipid based nanocarriers such as nanoliposomes were developed to increase the bioavailability of bioactive compounds. Since the function of nanoliposomes containing vitamins on the body has a direct relationship with the quality of produced nanoliposomes, this review study was planned to investigate the several aspects of liposomal characteristics such as size, polydispersity index, zeta potential, and encapsulation efficiency on the quality of synthesized vitamin-loaded nanoliposomes.

Curcumin-Loaded Liposome Preparation in Ultrasound Environment under Pressurized Carbon Dioxide

Curcumin-loaded liposomes were prepared using a supercritical carbon dioxide (SCCO2)−ultrasound environment system. The experiments were performed at temperatures of 40−70 °C and pressures of 10−25 MPa in a batch system with ultrasonication for 60 min. Transmission electron microscopy (TEM) images revealed liposome products with spherical morphologies and diameters of <100 nm. Dynamic light scattering (DLS) analysis indicated that the curcumin-loaded liposome nanosuspension exhibited good stability. Changing the operating conditions influenced the amount of liposome-encapsulated curcumin; as the operating temperature or pressure increased, the diameter of the liposome products and the amount of liposome-encapsulated curcumin increased and decreased, respectively. Herein, we described an innovative and practical organic-solvent-free method for generating liposomes from phospholipids.

Preparation of Liposomes from Soy Lecithin Using Liquefied Dimethyl Ether

We investigated a method to prepare liposomes; soy lecithin was dissolved in liquefied dimethyl ether (DME) at 0.56 MPa, which was then injected into warm water. Liposomes can be successfully prepared at warm water temperatures above 45 °C. The transmission electron microscopy (TEM) images of the obtained liposomes, size distribution, ζ-potential measurements by dynamic light scattering and the amount of residual medium were compared by gas chromatography using the conventional medium, diethyl ether. The size of the obtained liposomes was approximately 60-300 nm and the ζ-potential was approximately -57 mV, which was almost the same as that of the conventional medium. Additionally, for the conventional media, a large amount remained in the liposome dispersion even after removal by depressurization and dialysis membrane treatment; however, liquefied DME, owing to its considerably low boiling point, was completely removed by depressurization. Liquefied DME is a very attractive medium for the preparation of liposomes because it does not have the toxicity and residue problems of conventional solvents or the hazards of ethanol addition and high pressure of supercritical carbon dioxide; it is also environmentally friendly.

Mechanism of enhancing foaming properties of egg white by super critical carbon dioxide treatment

The effect of supercritical carbon dioxide (SCCD) treatment at varying processing time (30-90 min) on foaming and structure properties of egg white protein (EWP) were studied in this paper. The highest foaming ability (107.7%) was obtained after 60 min SCCD treatment, which was 3.6-fold to the control group. Foaming stability kept stable under the processing time of 75 min. Results of surface tension, surface hydrophobicity, rheological properties and particle size indicated that protein was easier to spread to the gas-liquid interface and generate molecular rearrangement. Circular dichroism (CD) and Endogenous fluorescence spectrum showed that there were slight changes on the secondary structure of EWP. The α-helical structure of the protein was destroyed and the particle size became uneven, which indicated that the protein structure became more flexible and loose. The results of this study indicate that SCCD treatment had a potential to be implemented to enhance foaming properties of EWP.

Nanoliposomes of Supercritical Carbon Dioxide Extract of Small Cardamom Seeds Redresses Type 2 Diabetes and Hypercholesterolemia

BACKGROUND & OBJECTIVES

In our previous investigation, oral administration of 1,8- cineole-rich supercritical carbon dioxide extract of small cardamom seeds in Wistar albino rats resulted in achieving normal fasting blood glucose (FBG) and serum cholesterol levels. The objective of this study was to further protect the aforesaid extract and to enhance its in vivo therapeutic efficacies in redressing type 2 diabetes and hypercholesterolemia, by encapsulating it as nanoliposomes. Patents related to nanoliposomes have been revised thoroughly.

METHODS

PEGylated nanoliposomes of the aforesaid extract were formulated using soya phosphatidylcholine and Tween 80 by probe-sonication. These nanoliposomes were subjected to in vitro characterizations and were orally administered to Wistar albino rats at three different doses viz. 550, 175 and 55 mg/kg b.w. for detailed investigation of their antidiabetic and hypocholesterolemic efficacies.

RESULTS

FT-IR, DSC and XRD analyses, HLB value (16), entrapment efficiency (84%) and release kinetics (obeying Higuchi model) revealed that the nanoliposomes were o/w type and were hydrophilic. They exhibited appreciable in vitro antioxidant potency (59% DPPH scavenging activity) owing to a synergistic consortium of antioxidants present therein. Oral administration of the liposomes in rats at 550 mg/kg b.w. could restore their normal FBG levels and serum lipid profiles on day 35, with desirable up-down regulations of related key enzymes. The iHOMA2 model could successfully predict the effects of nanoliposomes on insulin sensitivity and glucose uptake in rat liver and brain, respectively.

CONCLUSION

Nanoliposome of 1,8-cineole rich extract of small cardamom seeds is a new biotherapeutic in redressing type 2 diabetes and hypercholesterolemia.

Nanocharacterization of liposomes for the encapsulation of water soluble compounds from Cordyceps sinensis CS1197 by a supercritical gas anti-solvent technique

Nano-liposomes were designed for the sustained release of water soluble compounds from C. sinensis CS1197 using a supercritical gas anti-solvent (SC-GAS) method at various pressures, temperatures and Tween 80 concentrations. The SC-GAS method was compared to the Bangham method of liposome production in terms of mean diameter, coefficient of uniformity (C_u), encapsulation efficiency, morphology, viscosity and actual energy required for liposome formation. Liposome production via the SC-GAS method under optimized formulation conditions, i.e., 180 bar; 50 °C; 0.75% Tween 80; and a depressurization rate of 25 bar min⁻¹, yielded nano-liposomes exhibiting the lowest C_u value (1.10 ± 0.012) with a mean diameter of 0.072 ± 0.002 μm and better encapsulation efficiencies of 75.48 ± 2.5, 74.9 ± 2.1 and 70.23 ± 2.9% for adenosine, cordycepin and polysaccharides, respectively. Nano-liposomes were characterized using FTIR, XRD, DSC and TGA techniques. The stability indices and viscosities of the prepared liposome suspensions indicated good stability of up to 2 months and near-Newtonian behavior. The in vitro release of CS1197 water soluble compounds exhibited biphasic and sustained release patterns.

Nano-liposomes were designed for the sustained release of water soluble compounds from C. sinensis CS1197 using a supercritical gas anti-solvent (SC-GAS) method at various pressures, temperatures and Tween 80 concentrations.

Recent Advances in Lipid-Based Vesicles and Particulate Carriers for Topical and Transdermal Application

In the recent decade, skin delivery (topical and transdermal) has gained an unprecedented popularity, especially due to increased incidences of chronic skin diseases, demand for targeted and patient compliant delivery, and interest in life cycle management strategies among pharmaceutical companies. Literature review of recent publications indicates that among various skin delivery systems, lipid-based delivery systems (vesicular carriers and lipid particulate systems) have been the most successful. Vesicular carriers consist of liposomes, ultradeformable liposomes, and ethosomes, while lipid particulate systems consist of lipospheres, solid lipid nanoparticles, and nanostructured lipid carriers. These systems can increase the skin drug transport by improving drug solubilization in the formulation, drug partitioning into the skin, and fluidizing skin lipids. Considering that lipid-based delivery systems are regarded as safe and efficient, they are proving to be an attractive delivery strategy for the pharmaceutical as well as cosmeceutical drug substances. However, development of these delivery systems requires comprehensive understanding of physicochemical characteristics of drug and delivery carriers, formulation and process variables, mechanism of skin delivery, recent technological advancements, specific limitations, and regulatory considerations. Therefore, this review article encompasses recent research advances addressing the aforementioned issues.

Biodegradable polymeric nanostructures in therapeutic applications: opportunities and challenges

Biodegradable polymeric nanostructures (BPNs) have shown great promise in different therapeutic applications such as diagnosis, imaging, drug delivery, cosmetics, organ implants, and tissue engineering.

Nano-engineering of liposomes using a supercritical CO2 mediated gas anti-solvent method

Nano-liposomes were designed using a supercritical (SC) gas anti-solvent (GAS) method.

Multifunctional nanovesicle-bioactive conjugates prepared by a one-step scalable method using CO2-expanded solvents

The integration of therapeutic biomolecules, such as proteins and peptides, in nanovesicles is a widely used strategy to improve their stability and efficacy. However, the translation of these promising nanotherapeutics to clinical tests is still challenged by the complexity involved in the preparation of functional nanovesicles and their reproducibility, scalability, and cost production. Here we introduce a simple one-step methodology based on the use of CO2-expanded solvents to prepare multifunctional nanovesicle-bioactive conjugates. We demonstrate high vesicle-to-vesicle homogeneity in terms of size and lamellarity, batch-to-batch consistency, and reproducibility upon scaling-up. Importantly, the procedure is readily amenable to the integration/encapsulation of multiple components into the nanovesicles in a single step and yields sufficient quantities for clinical research. The simplicity, reproducibility, and scalability render this one-step fabrication process ideal for the rapid and low-cost translation of nanomedicine candidates from the bench to the clinic.

Nanostructuring molecular materials as particles and vesicles for drug delivery, using compressed and supercritical fluids

The structuring of synthetic and biological therapeutic actives as micro- and nano-particulate materials is a widely accepted formulation strategy to improve efficacy and reduce the toxicity of drugs. However, the development of efficient production platforms that enable the formulation of these nanomedicines at an industrial scale and with the quality requirements imposed by regulatory agencies remains a challenge. In this framework, compressed fluid-based methods are promising technologies for the controlled and reproducible preparation of uniform micro- and nano-particulate nanomedicines at a large scale. This review provides an overall but practical knowledge about what has been achieved so far in the field of compressed fluids applied to the preparation of solid micro- and nanoparticles and vesicles as drug delivery systems. In addition, recent examples of application of these technologies to the production of polymeric nanostructured microparticles highly loaded with gentamicin and to the preparation of uniform cholesterol-rich vesicular systems are explained.