1H NMR study of the interaction of trans-resveratrol with soybean phosphatidylcholine liposomes

The effect of trans-resveratrol on the physicochemical properties of lipid membranes with different cholesterol content

Resveratrol is one of the most popular phytoalexins, which naturally occurs in grapes and red wine. This compound not only has beneficial effects on the human body, especially on the cardiovascular system, but also has antiviral, antibacterial and antifungal properties. In addition, resveratrol may have therapeutic effects against various types of cancer. The mechanism of action of resveratrol is not fully understood, but it is suspected that one of the most important steps is its interaction with the cell membrane and changing its molecular organization. Therefore, in the present study, we investigated the effects of resveratrol at different concentrations (0-75 μM) on model membranes composed of POPC, SM and cholesterol, in systems with different cholesterol contents and a constant POPC/SM molar ratio (1:1). Our tests included systems containing 5, 15 and 33.3 mol% cholesterol. Tests were carried out for monolayers using the Langmuir monolayer technique supported by Brewster angle microscopy and penetration experiments. Bilayer (liposome) experiments included calcein release, steady-state DPH fluorescence anisotropy and partition coefficients. The results showed that resveratrol interacts with model cell membranes (lipid monolayers and lipid bilayers), and its incorporation into membranes is accompanied by changes in their physicochemical parameters, such as lipid packing, fluidity and permeability. Furthermore, we showed that the cholesterol content of the membrane significantly affects the degree of incorporation of resveratrol into the model membrane, which may indicate that the molecular mechanism of action of this compound is closely related to its interactions with lipid rafts, domains responsible for regulating various cellular functions.

Exploring novel and fast stability or sameness evaluation tool for different categories of injectable formulations

The establishment of drug product stability and sameness is the heart of generic formulation development. For regulatory filing, various instrumental methods are used on a case basis to establish the generic and innovator product sameness in multiple aspects. Here in the present study, we explored the applicability of the Time-correlated single photon counting (TCS-PC) technique as a fast, reliable, and nondestructive method for establishing the sameness of three different categories of injectable formulations, namely, Amphotericin B liposome for injection, enoxaparin injection, and iron sucrose injection. All three category formulations were evaluated in their native and artificially induced post degradation state to identify the discrimination power of the used instrumental techniques. The degradation of materials were confirmed by high performance liquid chromatography (HPLC). Based on the product category, pre and post-degradation samples were evaluated by selective instrumental methods like differential scanning calorimetry (DSC), nuclear magnetic resonance (NMR), fluorescence spectroscopy, particle size analysis by dynamic light scattering (DLS), small angle X-ray scattering (SAXS), Raman spectroscopy, inductively coupled plasma optical-emission spectrometry (ICP-OES) and circular dichroism study. All pre and post-degradation samples were further analyzed by TCS-PC. We observed that, TCS-PC can identify the differences between the initial and post degradation samples in very less time with promising discrimination power across the different injectable formulation types. Thus TCS-PC can be used as a fast and promising stability or sameness evaluation tool for different injectable drug products.

Development and characterization of catechin-in-cyclodextrin-in-phospholipid liposome to eradicate MRSA-mediated surgical site infection: Investigation of their anti-infective efficacy through in vitro and in vivo studies

Methicillin-resistant Staphylococcus aureus (MRSA) is one of the prime pathogens responsible for surgical site infection (SSI). Treatment of SSI remains challenging because of resistant nature of MRSA, which is a major threat in recent years. Our previous work revealed the antibacterial potential of catechin isolated from cashewnut shell against MRSA. However, the application of catechin to treat MRSA-mediated SSI is hampered because of its poor solubility and low trans-dermal delivery. Hence, the present study focused on developing catechin-in-cyclodextrin-in-phospholipid liposome (CCPL) and evaluating its physicochemical characteristics and anti-infective efficacy through in vitro and in vivo models. Encapsulation of catechin with β-cyclodextrin and soybean lecithin was confirmed through UV-Vis spectroscopy, FTIR, and XRD techniques, while TEM imaging revealed the size of CCPL (206 nm). The CCPL displayed a higher level of water solubility (25.13%) and in vitro permeability (42.14%) compared to pure catechin. A higher level of encapsulation efficiency (98.9%) and antibacterial activity (19.8 mm of ZOI and 31.25 μg/mL of MIC) were noted in CCPL compared to the catechin/cyclodextrin complex. CCPL recorded significant and dose-dependent healing of the incision, significant reduction of bacterial count, improved epithelization, and effective prevention of inflammation in skin samples of SSI-induced Balb/c mice. Data of the present work suggest that the CCPL could be considered as a novel and potential candidate to mitigate MRSA-mediated SSI after clinical trials.

Understanding molecular mechanisms of biologics drug delivery and stability from NMR spectroscopy

Protein therapeutics carry inherent limitations of membrane impermeability and structural instability, despite their predominant role in the modern pharmaceutical market. Effective formulations are needed to overcome physiological and physicochemical barriers, respectively, for improving bioavailability and stability. Knowledge of membrane affinity, cellular internalization, encapsulation, and release of drug-loaded carrier vehicles uncover the structural basis for designing and optimizing biopharmaceuticals with enhanced delivery efficiency and therapeutic efficacy. Understanding stabilizing and destabilizing interactions between protein drugs and formulation excipients provide fundamental mechanisms for ensuring the stability and quality of biological products. This article reviews the molecular studies of biologics using solution and solid-state NMR spectroscopy on structural attributes pivotal to drug delivery and stability. In-depth investigation of the structure-function relationship of drug delivery systems based on cell-penetrating peptides, lipid nanoparticles and polymeric colloidal, and biophysical and biochemical stability of peptide, protein, monoclonal antibody, and vaccine, as the integrative efforts on drug product design, will be elaborated.

Lipid Coating of Chitosan Nanogels for Improved Colloidal Stability and In Vitro Biocompatibility

Chitosan-based carriers have coined their position as delivery agents. When assembled with polyanions into nanogels (NG), these vectors have enabled the delivery of drugs, genes, and proteins to a myriad of applications. However, the chemical and colloidal instability of chitosan nanoformulations in physiologically compatible media prejudices in vitro biocompatibility and, thus, scale-up applications. To overcome this issue, we envisaged the coating of chitosan nanogel with phospholipids. In this investigation, we report a two-stage synthesis of hybrid lipid-coated chitosan nanogels, named nanolipogels (NLG), to improve colloidal stability and in vitro biocompatibility over chitosan NG. Practically, we employed a mixing platform to first prepare chitosan NG by ionic gelation, dilute the suspension, and, in a second stage, coat the NG with lipids. We demonstrate that lipid coating increased particle size and reversed the ζ-potential to negative values, suggesting the successful formation of NLG, while maintaining a homogeneous size distribution (PDI < 0.25). Furthermore, multiple light scattering analysis confirmed NLG improved colloidal stability in phosphate buffer saline and cell culture medium, with respect to NG. Finally, lipid coating completely abrogated the cytotoxicity of NG when incubated at 50 μg·mL^-1 with HeLa, U87, or b.End3 cell lines and significantly improved the biocompatibility at 100 and 150 μg·mL^-1. Future investigations will explore how the lipid coating affects drug loading, release profile, and the ability of NLG to deliver drugs and genes in vitro.

Comparative Study on Curcumin Loaded in Golden Pompano (Trachinotus blochii) Head Phospholipid and Soybean Lecithin Liposomes: Preparation, Characteristics and Anti-Inflammatory Properties

In this study, we compared the characteristics and in vitro anti-inflammatory effects of two curcumin liposomes, prepared with golden pompano head phospholipids (GPL) and soybean lecithin (SPC). GPL liposomes (GPL-lipo) and SPC liposomes (SPC-lipo) loaded with curcumin (CUR) were prepared by thin film extrusion, and the differences in particle size, ζ-potential, morphology, and storage stability were investigated. The results show that GPL-lipo and SPC-lipo were monolayer liposomes with a relatively small particle size and excellent encapsulation rates. However, GPL-lipo displayed a larger negative ζ-potential and better storage stability compared to SPC-lipo. Subsequently, the effects of phospholipids in regulating the inflammatory response of macrophages were evaluated in vitro, based on the synergistic effect with CUR. The results showed that both GPL and SPC exerted excellent synergistic effect with CUR in inhibiting the lipopolysaccharide (LPS)-induced secretion of nitric oxide (NO), reactive oxygen species (ROS), and pro-inflammatory genes (tumor necrosis factor (TNF)-α, interleukin 1β (IL-β), and interleukin 6 (IL-6)) in RAW264.7 cells. Interestingly, GPL-lipo displayed superior inhibitory effects, compared to SPC-lipo. The findings provide a new innovative bioactive carrier for development of stable CUR liposomes with good functional properties.

Study of Resveratrol's Interaction with Planar Lipid Models: Insights into Its Location in Lipid Bilayers

Resveratrol, a polyphenolic molecule found in edible fruits and vegetables, shows a wide range of beneficial effects on human health, including anti-microbial, anti-inflammatory, anti-cancer, and anti-aging properties. Due to its poor water solubility and high liposome-water partition coefficient, the biomembrane seems to be the main target of resveratrol, although the mode of interaction with membrane lipids and its location within the cell membrane are still unclear. In this study, using electrophysiological measurements, we study the interaction of resveratrol with planar lipid membranes (PLMs) of different composition. We found that resveratrol incorporates into palmitoyl-oleoyl-phosphatidylcholine (POPC) and POPC:Ch PLMs and forms conductive units unlike those found in dioleoyl-phosphatidylserine (DOPS):dioleoyl-phosphatidylethanolamine (DOPE) PLMs. The variation of the biophysical parameters of PLMs in the presence of resveratrol provides information on its location within a lipid double layer, thus contributing to an understanding of its mechanism of action.

Inulin-pluronic-stearic acid based double folded nanomicelles for pH-responsive delivery of resveratrol

Herein, we introduce a novel amphiphilic bioconjugate (INU-F68-SA), synthesized by functionalization of pluronic F68 with a polysaccharide inulin (INU) and a lipid stearic acid (SA). The synthesis of INU-F68-SA was confirmed by FTIR and ¹H-NMR analysis. INU-F68-SA can self-assemble into nanomicelles and therefore, its application in delivering of hydrophobic resveratrol (RSV) was investigated. The RSV-loaded INU-F68-SA nanomicelles (RSNM) had about 172 nm size, spherical shape, 0.237 polydispersity index, and -18 mV zeta potential. More importantly, the RSNM showed high drug entrapment efficiency, controlled drug release and protection of drug during storage. The RSNM significantly enhanced the cytotoxicity of RSV against colorectal cancer cells by inducing apoptosis and changing mitochondrial membrane potential. Further, in-vivo pharmacokinetic experiment indicated an improvement in pharmacokinetics of RSV after administering as RSNM. Thus, the use of self-assembled nanomicelles of amphiphilic INU-F68-SA bioconjugate could be a better alternative to overcome the poor in-vitro and in-vivo performance of RSV.