Energetic mixing of anti-SNAP25 on lipid monolayers: degree of saturation of C18 fatty acids

In our study, various mixtures of C18 fatty acids with different degrees of saturation in their hydrocarbon chain, namely stearic acid (SA), oleic acid (L1), linoleic acid (L2), and linolenic acid (L3), and a polyclonal antibody, anti-synaptosome-associated protein of 25 kDa (SNAP25) (AS25), have been investigated using the Langmuir–Blodgett (LB) technique accompanied by atomic force microscopy (AFM) imaging. The cis-double bonds in unsaturated lipids (L1, L2, and L3) have kinks in their molecular conformation and thus could not pack as tightly and uniformly as SA. The bends and kinks in the molecular structure may interfere with the packing of the lipid monolayer which will promote fluidity as shown in the analyzed compressibility modulus (Cs−1) data. The negative values of Gibbs free energy of mixing (ΔGmix) of C18 fatty acids/AS25 confirm the spontaneity interaction of AS25 molecules on the monolayers. The amount of AS25 incorporated into the monolayer strongly affected the thermodynamic properties of the lipid monolayers. AFM surface roughness analyses also indicate that AS25 molecules are strongly bounded on the surface membrane as predicted by the obtained energetic data. In comparison to all C18 fatty acids studied, the strongest intermolecular interaction is observed in L1 at the investigated ranges. In particular, at mole ratio of 26:1, the most negative ΔGmix is observed at L1. Thus, we can draw the conclusion that AS25 is best mixed with L1. This L1/AS25 ratio mimicking a half bilayer membrane serves as a very useful reference in preparing fatty-acid nanoimmunoliposomes as the targeted drug-delivery vehicles for cancer therap

Optimization and characterization of fatty acid esters (FAES) based nanostructured lipid carrier (NLC) by Box-Behnken analysis

An unfavorable rate of toxicity and hydrophobicity of active substance in water has prompted the development of an improved active ingredients delivery systems such as nanostructured lipid carriers (NLC). This present study investigates varying components of NLCs compositions to achieve an optimized and stable colloidal suspension of NLCs through Box-Behnken design analysis for potential use as an active substance carrier system. The optimised formulation is comprised of 2.9% stearic acid, 0.4% MCT, 0.3% IPM, 0.37% Tween 20, 0.23% Span 20 and 96% deionised water (DW). The mean particle size, polydispersity index, and zeta potential of the optimized NLCs were 322±13.5 nm, 0.199±0.04, and -36±0.1 mV, respectively. Based on the TEM micrograph, NLCs can be observed as having an elongated spherical shape with a dense appearance

PEGylated Oleic Acid-Lecithin Liposomes (POLL) for anticancer drug delivery

Cancer is a major health issue, conferring to more than 14.5 million deaths worldwide. Liposomes, self-assembly amphiphilic bilayer molecules, served as excellent alternative vehicles due to their ability to encapsulate both hydrophobic and hydrophilic anticancer drugs. Conventional liposomes, comprised mainly phospholipids are cost-ineffective, unstable, and easily degraded by the external environment. In this study, we introduced PEGylated oleic acid-lecithin liposomes constructed by using C-18 monounsaturated fatty acids (oleic acid) and soy lecithin, in the presence of DOPEPEG2000 in pH7.4, above their glass transition temperature, Tg, by employing the simple thin layer lipid hydration method. FTIR spectrum of oleic acid, soy lecithin, and DOPEPEG2000 was studied. The average particle size without further mechanical interference was 1102.3 nm while the zeta potential value was -18 mV, which is compatible with the zeta potential of the red blood cell. The polydispersity index (PDI) was reduced by 46.2% with the incorporation of the DOPEPEG2000. The morphological study using OPM showed the presence of spherical shape liposomes that exhibit the birefringence effect under the light field and Maltese cross under the dark field. Encapsulation of folinic acid, methotrexate, doxorubicin, or irinotecan resulted in greater than 75% encapsulation efficiency (EE). Half-maximal inhibitory concentration, IC50, was significantly reduced in POLL as compared to free anticancer drugs. Our data demonstrate POLL may be a promising alternative vehicle to deliver various anticancer drugs to targeted tumour sites

(2-{[1,1-Bis(hydroxy­meth­yl)-2-oxidoeth­yl]imino­meth­yl}-4-chloro­phenolato-κ3 N,O,O′)dibutyl­tin(IV)

The Schiff base ligand in the title compound, [Sn(C4H9)2(C11H12ClNO4)], chelates to the Sn atom through the two deprotonated O atoms, as well as through the N atom, to confer an overall cis-C2SnNO2 trigonal-bipyramidal geometry at tin [C—Sn—C = 130.3 (1)°]. The hydr­oxy groups engage in O—H⋯O hydrogen bonding with the O atoms of adjacent mol­ecules, generating a chain running along the c axis

Synthesis and characterization of acylated low molecular weight chitosan and acylated low molecular weight phthaloyl chitosan

Oral drug delivery is one of the most convenient routes due to its painless administration and high patient compliance. However, oral administration is becoming more difficult to be conducted due to its poor water solubility, poor dissolution rate, and low oral bioavailability in the gastrointestinal tract. Herein, we develop a strategy to produce a chemically modified chitosan using depolymerization and introducing hydrophobic groups onto the chitosan backbone through acylation. By modifying the structure of chitosan, we aim to overcome limitations of drug delivery before and after the oral administration. The successful acylation of protected (using phthalic anhydride) chitosan and unprotected (without phthalic anhydride) chitosan was proved by Fourier transform infrared (FTIR). FTIR was conducted not only to characterize the functional group changes but also to find quantization of degree of acylation (DA) and the degree of substitution (DS) of chitosan before and after acylation. The particle size of chitosan was found ranges from 300-500 nm with zeta potential value shifted from -50 mV to a more positive value as acid anhydrides concentration increased. The Field Emission Scanning Electron Microscopy (FESEM) images showed the low molecular weight of chitosan and acylated chitosan nanoparticle possess non-spherical form with hollow structure. In addition, the size obtained was in accordance with the size measured by particle size. Hydrophobically modified chitosan has been successfully synthesized via acylation on both primary hydroxyl and amine groups on the backbone of chitosan. This chemically modified chitosan can enhance drug solubilization as well as improving biocompatibility and degradability

Preparation and characterization of PEGylated C18 fatty acids/Anti-SNAP25 antibody-targeted Liposomes

Background: Unsaturated C18 fatty acids, such as oleic acid (L1), linoleic acid (L2), and linolenic acid (L3), are a good choice of lipids to prepare liposomes. They are inexpensive, biocompatible, nontoxic, and readily available compared with phospholipids. Moreover, cis-double bonds of unsaturated fatty acids prevent the packing of molecules which increases membrane fluidity in liposomes making them a good choice of starting materials to prepare liposomes. Objective: Unsaturated C18 fatty acid liposomes, as well as their PEGylated and nonPEGylated antibody-targeted liposomes, were prepared and characterized. Method: The particle size and zeta potential of the prepared liposomes (1 mM, pH = 7.4) for 28 and 14 days, respectively, were monitored and characterized. Membrane-bound antibodies Anti-SNAP25 (AS25) and DOPE PEG2000 (DP) were conjugated to pure C18 fatty acid liposomes to achieve stable fatty acid formulations. Results: The mean particle sizes of pure L1, L2, and L3 liposome solutions were 125, 129, and 122 nm respectively, while their polydispersity index values were 0.28, 0.21, and 0.40 respectively. A large negative zeta potential value of 45 mV was observed due to anionic carboxylate head-group of pure liposomes. The incorporation of AS25 into L1/DP, L2/DP, and L3/DP liposome solutions stabilized their mean particle size and zeta potential measurements over 28 and 14 days, respectively. Conclusion: L1/DP/AS25 was found to be the most stable PEGylated antibody-targeted liposome system because its particle size remained between 90 and 125 nm in 28 days. Transmission electron microscopy observations also supported the incorporation of AS25 and DP on the membrane surface as predicted

Optimization of processing parameters for the preparation of phytosterol microemulsions by the solvent displacement method

The purpose of this study was to optimize the parameters involved in the production of water-soluble phytosterol microemulsions for use in the food industry. In this study, response surface methodology (RSM) was employed to model and optimize four of the processing parameters, namely, the number of cycles of high-pressure homogenization (1−9 cycles), the pressure used for high-pressure homogenization (100−500 bar), the evaporation temperature (30−70 °C), and the concentration ratio of microemulsions (1−5). All responses—particle size (PS), polydispersity index (PDI), and percent ethanol residual (%ER)—were well fit by a reduced cubic model obtained by multiple regression after manual elimination. The coefficient of determination (R2) and absolute average deviation (AAD) value for PS, PDI, and %ER were 0.9628 and 0.5398%, 0.9953 and 0.7077%, and 0.9989 and 1.0457%, respectively. The optimized processing parameters were 4.88 (approximately 5) homogenization cycles, homogenization pressure of 400 bar, evaporation temperature of 44.5 °C, and concentration ratio of microemulsions of 2.34 cycles (approximately 2 cycles) of high-pressure homogenization. The corresponding responses for the optimized preparation condition were a minimal particle size of 328 nm, minimal polydispersity index of 0.159, and <0.1% of ethanol residual. The chi-square test verified the model, whereby the experimental values of PS, PDI, and %ER agreed with the predicted values at a 0.05 level of significance

Local application of osteoprotegerin-chitosan gel in critical-sized defects in a rabbit model

Background Osteoprotegerin (OPG) is used for the systemic treatment of bone diseases, although it has many side effects. The aim of this study was to investigate a newly formulated OPG-chitosan gel for local application to repair bone defects. Recent studies have reported that immunodetection of osteopontin (OPN) and osteocalcin (OC) can be used to characterise osteogenesis and new bone formation. Methods The osteogenic potential of the OPG-chitosan gel was evaluated in rabbits. Critical-sized defects were created in the calvarial bone, which were either left unfilled (control; group I), or filled with chitosan gel (group II) or OPG-chitosan gel (group III), with rabbits sacrificed at 6 and 12 weeks. Bone samples from the surgical area were decalcified and treated with routine histological and immunohistochemical protocols using OC, OPN, and cathepsin K (osteoclast marker) antibodies. The toxicity of the OPG-chitosan gel was evaluated by biochemical assays (liver and kidney function tests). Results The mean bone growth in defects filled with the OPG-chitosan gel was significantly higher than those filled with the chitosan gel or the unfilled group (p < 0.05). At 6 and 12 weeks, the highest levels of OC and OPN markers were found in the OPG-chitosan gel group, followed by the chitosan gel group. The number of osteoclasts in the OPG-chitosan gel group was lower than the other groups. The results of the liver and kidney functional tests indicated no signs of harmful systemic effects of treatment. In conclusion, the OPG-chitosan gel has many characteristics that make it suitable for bone repair and regeneration, highlighting its potential benefits for tissue engineering applications

Preparation and characterization of chitosan-coated oleic acid liposomes for intravenous delivery

Liposome has been studied as a potential carrier for targeting and controlled drug delivery. However, poor stability remains a challenge because it can lead to drug leakage from the vesicles thus reduce the effectiveness towards the target cell. For this aim, the present study incorporated the low molecular weight chitosan (LMWC) into the oleic acid liposome to maintain the stability and prolong the lifetime in the blood circulation. The thin-film hydration method was employed to prepare the oleic acid liposomes prior to coating them with LMWC. The stability of the liposomes was determined by the measurement of particle size and zeta potential for 28 days. The morphology of the liposome was confirmed by observing the shape under transmission electron microscopy (TEM) and it showed almost spherical in shape. The average particle size increased to 201.23 nm and -51.4 mV when 5 mg of LMWC was added to the oleic acid liposome. The increase of particle size and zeta potential of LMWC-coated liposome indicated that polymer-liposome interaction had changed the stability of liposome thus this invention could be useful for delivering active ingredients through intravenous delivery