Sphingomyelin-based liposomes with different cholesterol contents and polydopamine coating as a controlled delivery system

Scalable microfluidic method for tunable liposomal production by a design of experiment approach

Liposomes constitute a widespread drug delivery platform, gaining more and more attention from the pharmaceutical industry and process development scientists. Their large-scale production as medicinal products for human use is all but trivial, especially when parenteral administration is required. In this study an off-the-shelf microfluidic system and a methodological approach are presented for the optimization, validation and scale-up of highly monodisperse liposomes manufacturing. Starting from a Doxil®-like formulation (HSPC, MPEG-DSPE and cholesterol), a rational approach (Design of Experiments, DoE) was applied for the screening of the process parameters affecting the quality attributes of the product (mainly size and polydispersity). Additional DoEs were conducted to determine the effect of critical process parameters (cholesterol concentration, total flow rate TFR and flow rate ratio FRR), thus assessing the formulation and process robustness. A scale-up was then successfully accomplished. The procedure was applied to a Marqibo®-like formulation as well (sphingomyelin and cholesterol) to show the generality of the proposed formulation, process development and scale-up approach. The application of the system and method herein presented enables the large-scale manufacturing of liposomes, in compliance with the internationally recognized regulatory standards for pharmaceutical development (Quality by Design).

Polydopamine-Modified Liposomes: Preparation and Recent Applications in the Biomedical Field

Polydopamine (PDA) is a bioinspired polymer that has unique and desirable properties for emerging applications in the biomedical field, such as extraordinary adhesiveness, extreme ease of functionalization, great biocompatibility, large drug loading capacity, good mucopenetrability, strong photothermal capacity, and pH-responsive behavior. Liposomes are consolidated and attractive biomimetic nanocarriers widely used in the field of drug delivery for their biocompatibility and biodegradability, as well as for their ability to encapsulate hydrophobic, hydrophilic, and amphiphilic compounds, even simultaneously. In addition, liposomes can be decorated with appropriate functionalities for targeted delivery purposes. Thus, combining the interesting properties of PDA with those of liposomes allows us to obtain multifunctional nanocarriers with enhanced stability, biocompatibility, and functionality. In this review, a focus on the most recent developments of liposomes modified with PDA, either in the form of polymer layers trapping multiple vesicles or in the form of PDA-coated nanovesicles, is proposed. These innovative PDA coatings extend the application range of liposomes into the field of biomedical applications, thereby allowing for easier functionalization with targeting ligands, which endows them with active release capabilities and photothermal activity and generally improves their interaction with biological fluids. Therefore, hybrid liposome/PDA systems are proposed for surface-mediated drug delivery and for the development of nanocarriers intended for systemic and oral drug delivery, as well as for multifunctional nanocarriers for cancer therapy. The main synthetic strategies for the preparation of PDA-modified liposomes are also illustrated. Finally, future prospects for PDA-coated liposomes are discussed, including the suggestion of potential new applications, deeper evaluation of side effects, and better personalization of medical treatments.

Engineered Lipidic Nanomaterials Inspired by Sphingomyelin Metabolism for Cancer Therapy

Sphingomyelin (SM) and its metabolites are crucial regulators of tumor cell growth, differentiation, senescence, and programmed cell death. With the rise in lipid-based nanomaterials, engineered lipidic nanomaterials inspired by SM metabolism, corresponding lipid targeting, and signaling activation have made fascinating advances in cancer therapeutic processes. In this review, we first described the specific pathways of SM metabolism and the roles of their associated bioactive molecules in mediating cell survival or death. We next summarized the advantages and specific applications of SM metabolism-based lipidic nanomaterials in specific cancer therapies. Finally, we discussed the challenges and perspectives of this emerging and promising SM metabolism-based nanomaterials research area.

Structural Changes in Liposomal Vesicles in Association with Sodium Taurodeoxycholate

Liposomes composed of soy lecithin (SL) have been studied widely for drug delivery applications. The stability and elasticity of liposomal vesicles are improved by incorporating additives, including edge activators. In this study, we report the effect of sodium taurodeoxycholate (STDC, a bile salt) upon the microstructural characteristics of SL vesicles. Liposomes, prepared by the thin film hydration method, were characterized by dynamic light scattering (DLS), small-angle neutron scattering (SANS), electron microscopy, and rheological techniques. We noticed a reduction in the size of vesicles with the incremental addition of STDC. Initial changes in the size of spherical vesicles were ascribed to the edge-activating action of STDC (0.05 to 0.17 µM). At higher concentrations (0.23 to 0.27 µM), these vesicles transformed into cylindrical structures. Morphological transitions at higher STDC concentrations would have occurred due to its hydrophobic interaction with SL molecules in the bilayer. This was ascertained from nuclear magnetic resonance observations. Whereas shape transitions underscored the deformability of vesicles in the presence of STDC, the consistency of bilayer thickness ruled out any dissociative effect. It was interesting to notice that SL-STDC mixed structures could survive high thermal stress, electrolyte addition, and dilution.

Towards understanding the binding affinity of lipid drug carriers to serum albumin

In the past several years there has been a rapid rise in the use of lipid-based drug formulations. In the case of intravenous drug administration the interaction of lipid carrier with serum albumin is crucial for the distribution of the bioactive molecules in the bloodstream and reaching the target tissue. In this work, we have explored the interaction of serum albumin with three-component lipid monolayer build of palmitoyloleoylphosphatidylcholine (POPC), sphingomyelin (SM), and cholesterol (Chol). Using wide range of lipid compositions and various concentrations of serum albumin we identified the factors governing the lipid-protein binding. Our study revealed that albumin can penetrate selectively the monolayers of POPC/SM/Chol depending on the lipid composition in the mixture. Moreover, the interaction of albumin with monolayer can be controlled by the molecular density of the film and the concentration of protein. The adsorbed albumin exists in the film on the top of lipid monolayer. This behavior may lead to the increase of the size and charge of the lipid carrier and affect the drug transport throughout the bloodstream. The results of this work provide essential physicochemical data that can be used for predicting the pharmacokinetic profile of lipid-based formulations.

Rationale utilization of phospholipid excipients: a distinctive tool for progressing state of the art in research of emerging drug carriers

Phospholipids have a high degree of biocompatibility and are deemed ideal pharmaceutical excipients in the development of lipid-based drug delivery systems, because of their unique features (permeation, solubility enhancer, emulsion stabilizer, micelle forming agent, and the key excipients in solid dispersions) they can be used in a variety of pharmaceutical drug delivery systems, such as liposomes, phytosomes, solid lipid nanoparticles, etc. The primary usage of phospholipids in a colloidal pharmaceutical formulation is to enhance the drug's bioavailability with low aqueous solubility [i.e. Biopharmaceutical Classification System (BCS) Class II drugs], Membrane penetration (i.e. BCS Class III drugs), drug uptake and release enhancement or modification, protection of sensitive active pharmaceutical ingredients (APIs) from gastrointestinal degradation, a decrease of gastrointestinal adverse effects, and even masking of the bitter taste of orally delivered drugs are other uses. Phospholipid-based colloidal drug products can be tailored to address a wide variety of product requirements, including administration methods, cost, product stability, toxicity, and efficacy. Such formulations that are also a cost-effective method for developing medications for topical, oral, pulmonary, or parenteral administration. The originality of this review work is that we comprehensively evaluated the unique properties and special aspects of phospholipids and summarized how the individual phospholipids can be utilized in various types of lipid-based drug delivery systems, as well as listing newly marketed lipid-based products, patents, and continuing clinical trials of phospholipid-based therapeutic products. This review would be helpful for researchers responsible for formulation development and research into novel colloidal phospholipid-based drug delivery systems.

Polydopamine-Modified Nanolime with High Kinetic Stability in Water for the Consolidation of Stone Relics

As a promising inorganic nanomaterial for the conservation of arenaceous sandstone-based relics such as wall painting, ancient building, stone heritage etc., nanolime (NL) has drawn increasing attention in recent years. Usually, NL needs to be dispersed into an alcoholic solution when applied. Nevertheless, a back-migration phenomenon of NL to the surface of the stone and delayed carbonation of NL enabled by alcohol do not guarantee good preservation effects. Dispersing NL into water can avoid the above issues. However, NL water suspension shows extremely poor kinetic stability, greatly restricting the penetration of NL into stone relics as well as bringing unfavorable impacts to the treated stone heritage. Here, we develop a facile method to synthesize polydopamine (PDA)-modified NL (PDA@NL). Characterizations demonstrate that PDA is uniformly distributed on the surface of NL particles though hydrogen bonds. In addition, the presence of PDA reduces the size of NL particles and achieves the highest specific surface area of NL reported to date. More importantly, water suspension of PDA@NL is far more stable than that of pure NL. The kinetic stability mechanism of PDA@NL in water is attributed to the lessened spatial interactions between NL particles, which is realized by the coverage of PDA on the surface of NL particles. Furthermore, the coverage of PDA does not inhibit carbonation. Within 105 h, NL in PDA@NL completes carbonation and obtains 93.7% calcite, which is comparable to that of NL suspension. Permeability tests prove that the PDA@NL suspension penetrates far deeper through stone specimens compared with the NL suspension. Additionally, PDA@NL presents good consolidation performances for stone samples. Our work opens a new direction for the modification of NL that will boost the studies of NL-modified materials as well as the conservation of cultural heritage.

Investigations on the influence of the structural flexibility of nanoliposomes on their properties

In the present study, nanoliposomes with tuneable structure elasticity were prepared by reverse-phase evaporation. Both Fluorescence Polarization and Fluorescence Resonance Energy Transfer was employed to characterize the structural elasticity of resultant nanoliposomes. Temozolomide, a kind of hydrophilic drug as the first-line treatment choice for glioblastoma, was encapsulated into nanoliposomes. The results showed that the flexibility of nanoliposomes gradually increased with sodium cholate, while decreasing with cholesterol, Labrafac CC and Labrafac PG adding. Furthermore, the structural flexibility of nanoliposomes was positively correlated with the encapsulation efficiency and release rate and cellular uptake. Our research reveals the structural flexibility of nanoliposomes could affect in vitro characteristics and thereafter in vivo behaviors of nanoliposomes.

Microfluidic Technology for the Production of Hybrid Nanomedicines

Microfluidic technologies have recently been applied as innovative methods for the production of a variety of nanomedicines (NMeds), demonstrating their potential on a global scale. The capacity to precisely control variables, such as the flow rate ratio, temperature, total flow rate, etc., allows for greater tunability of the NMed systems that are more standardized and automated than the ones obtained by well-known benchtop protocols. However, it is a crucial aspect to be able to obtain NMeds with the same characteristics of the previously optimized ones. In this study, we focused on the transfer of a production protocol for hybrid NMeds (H-NMeds) consisting of PLGA, Cholesterol, and Pluronic® F68 from a benchtop nanoprecipitation method to a microfluidic device. For this aim, we modified parameters such as the flow rate ratio, the concentration of core materials in the organic phase, and the ratio between PLGA and Cholesterol in the feeding organic phase. Outputs analysed were the chemico-physical properties, such as size, PDI, and surface charge, the composition in terms of %Cholesterol and residual %Pluronic® F68, their stability to lyophilization, and the morphology via atomic force and electron microscopy. On the basis of the results, even if microfluidic technology is one of the unique procedures to obtain industrial production of NMeds, we demonstrated that the translation from a benchtop method to a microfluidic one is not a simple transfer of already established parameters, with several variables to be taken into account and to be optimized.