Structural and therapeutic properties of salicylic acid-solubilized Pluronic solutions and hydrogels

Salicylic acid (SA) finds extensive applications in the treatment of rheumatic and skin diseases because of its analgesic, anti-inflammatory and exfoliating properties. As it is lipophilic in nature, there is a need for appropriate delivery systems to harness these properties for different applications. Herein, we examined the suitability of Pluronic P123/F127 micellar systems as delivery media by investigating the structural, flow and antimicrobial properties of P123/F127-SA solutions and hydrogels using DLS, SANS, rheological and zone inhibition measurement techniques. SA modulates the aggregation characteristics of these surfactant systems and brings about spherical-to-worm-like micelle-to-vesicular structural transitions in the hydrophobic Pluronic P123 system, a spherical-to-worm-like micellar transition in the mixed P123/F127 system and an onset of inter-micellar attraction in the hydrophilic Pluronic F127 system. SA-solubilized systems of both hydrophobic and hydrophilic Pluronics inhibit the growth of Gram-positive and Gram-negative bacteria with comparable MIC values. This suggests that the interaction of SA molecules with the bacterial cell membrane remains unobstructed upon encapsulation in Pluronic micelles. F127 hydrogel-based SA formulations with rheological properties suitable for topical applications and up to 15% SA loading were prepared. These will be useful SA ointments as F127 is an FDA-approved excipient for topical drug delivery applications. The results indicate that Pluronics remain effective as delivery agents for SA and exhibit interesting structural polymorphism upon its solubilization.

Organogels: "GelVolution" in Topical Drug Delivery - Present and Beyond

Topical drug delivery holds immense significance in dermatological treatments due to its non-invasive nature and direct application to the target site. Organogels, a promising class of topical drug delivery systems, have acquired substantial attention for enhancing drug delivery efficiency. This review article aims to explore the advantages of organogels, including enhanced drug solubility, controlled release, improved skin penetration, non-greasy formulations, and ease of application. The mechanism of organogel permeation into the skin is discussed, along with formulation strategies, which encompass the selection of gelling agents, cogelling agents, and additives while considering the influence of temperature and pH on gel formation. Various types of organogelators and organogels and their properties, such as viscoelasticity, non-birefringence, thermal stability, and optical clarity, are presented. Moreover, the biomedical applications of organogels in targeting skin cancer, anti-inflammatory drug delivery, and antifungal drug delivery are discussed. Characterization parameters, biocompatibility, safety considerations, and future directions in optimizing skin permeation, ensuring long-term stability, addressing regulatory challenges, and exploring potential combination therapies are thoroughly examined. Overall, this review highlights the immense potential of organogels in redefining topical drug delivery and their significant impact on the field of dermatological treatments, thus paving the way for exciting prospects in the domain.

Physicochemical properties of a new structural lipid from the enzymatical incorporation of flaxseed oil into mutton tallow

This study evaluated the physio-chemical properties of a structural lipid (SL) obtained by the enzymatical incorporation of flaxseed oil into mutton tallow (MT). By measuring the melting point, colour, safety, fatty acids, apparent viscosity, shear stress and volatile compounds of the samples, the results showed that compared to MT, SL exhibited lower L∗(lightness) value, melting point, apparent viscosity and shear stress (p < 0.05). Noteworthy, the Saturated fatty acids (SFA)content of MT was reduced from 61.46% to 25.49% (p < 0.05), although SL was found to be more prone to oxidation during storage. The clearest discrepancy in volatile compounds was the increase of heterocyclic compounds in SL. In summary, improving the edible properties of animal fats by adding vegetable oils is an effective solution, and SL may have a great potential to be developed into a high-quality product with improved nutritional composition of animal fat.

Microfluidic Droplet Cluster with Distributed Evaporation Rates as a Model for Bioaerosols

Aerosols and microdroplets are known to act as carriers for pathogens or vessels for chemical reactions. The natural occurrence of evaporation of these droplets has implications for the viability of pathogens or chemical processes. For example, it is important to understand how pathogens survive extreme physiochemical conditions such as confinement and osmotic stress induced by evaporation of aerosol droplets. Previously, larger evaporating droplets were proposed as model systems as the processes in the tiny aerosol droplets are difficult to image. In this context, we propose the concept of evaporation of capillary-clustered aqueous microdroplets dispersed in a thin oil layer. The configuration produces spatially segregated evaporation rates. It allows comparing the consequences of evaporation and its rate for processes occurring in droplets. As a proof of concept, we study the consequences of evaporation and its rate using Escherichia coli (E. coli) and Bacillus subtilis as model organisms. Our experiments indicate that the rate of evaporation of microdroplets is an important parameter in deciding the viability of contained microorganisms. With slow evaporation, E. coli could mitigate the osmotic stress by K⁺ ion uptake. Our method may also be applicable to other evaporating droplet systems, for example, microdroplet chemistry to understand the implications of evaporation rates.

Fabrication and Evaluation of Celecoxib Oral Oleogel to Reduce the Inflammation of Ulcerative Colitis

Oleogel consists of hydrophobic solvent and an oleogelator. In this study, attempts were made to study the influence of Celecoxib solubility, concentration and dispersability on its release, absorption, and biological performance. Oleogels were prepared to study the formulation variables on its stability and release. Castor oil was selected as the oil and the oleogelator concentration was 4.5% w/w. F3 revealed the highest release and stability compared to other formulae. The percent permeated across the rat intestine showed a 7.5-fold increase over free Celecoxib, and its lifetime was found to be greater than 18 months. The efficacy of free Celecoxib and oleogel formulae to treat rats with ulcerative colitis was done via the induction of ulcerative colitis (UC) through administration of 5% dextran sodium sulphate (DSS). Celecoxib besides its formulae significantly reduced the release of Leucine rich 2 glycoprotein (LRG), Myeloperoxidase (MPO), Tumor necrosis factor-α (TNF-α), proinflammatory cytokine expression, High mobility group box 1 (HMGB1), Nuclear factor kappa B (NF-ΚB), Trefoil Factor 3 (TFF3), Metalloproteinase-3 (MMP3), and miRNA31. Moreover, F3 significantly increased the colonic cAMP in DSS treated rats and reduced the intestinal inflammation beside healing of mucosa and restitution of the epithelium of the gastrointestinal tract.

Application of Analytical Methods for the Comprehensive Analysis of Oleogels-A Review

Numerous empirical studies have already been conducted on the innovative fat-replacing system defined as oleogel, creating a real urge for setting up a framework for future research, rather than conducting studies with arbitrary methods. This study re-evaluates the utility of some analyses and states some conclusions in order to eliminate the reluctance of food processors and consumers towards the utilization of oleogels as ingredients. The review presents extensively the methods applied for the characterization of various oleogels, while highlighting their addressability or inconveniences. The discussed methods were documented from the research published in the last five years. A classification of the methods is proposed based on their aims or the utility of the results, which either describe the nano-structure and the network formation, the quality of the resulting oleogel or its suitability as food ingredient or other edible purposes. The general conclusions drawn for some classes of oleogels were also revisited, in order to ease the understanding of the oleogel behaviour, to encourage innovative research approaches and to stimulate the progress in the state of art of knowledge.

Phase Inversion and Interfacial Layer Microstructure in Emulsions Stabilized by Glycosurfactant Mixtures

Identification of strategies to prolong emulsion kinetic stability is a fundamental challenge for many scientists and technologists. We investigated the relationship between the emulsion stability and the surfactant supramolecular organization at the oil-water interface. The pseudo-phase diagrams of emulsions formed by water and, alternatively, a linear or a branched oil, stabilized by mixtures of two sugar-based surfactants, Span80 and Tween80, are presented. The surfactant ordering and dynamics were analyzed by electron paramagnetic resonance (EPR) spectroscopy. In Oil-in-Water (O/W) emulsions, which are stable for more than four days, disordered surfactant tails formed a compact and viscous layer. In Water-in-Oil (W/O) emulsions, whose stability is much lower, surfactants formed an ordered layer of extended tails pointing toward the continuous apolar medium. If linear oil was used, a narrow range of surfactant mixture composition existed, in which emulsions did not demix in the whole range of water/oil ratio, thus making it possible to study the phase inversion from O/W to W/O structures. While conductometry showed an abrupt inversion occurring at a well-defined water/oil ratio, the surfactant layer microstructure changed gradually between the two limiting situations. Overall, our results demonstrate the interconnection between the emulsion stability and the surfactant layer microstructuring, thus indicating directions for their rational design.

Biocompatibility of Biomaterials for Nanoencapsulation: Current Approaches

Nanoencapsulation is an approach to circumvent shortcomings such as reduced bioavailability, undesirable side effects, frequent dosing and unpleasant organoleptic properties of conventional drug delivery systems. The process of nanoencapsulation involves the use of biomaterials such as surfactants and/or polymers, often in combination with charge inducers and/or ligands for targeting. The biomaterials selected for nanoencapsulation processes must be as biocompatible as possible. The type(s) of biomaterials used for different nanoencapsulation approaches are highlighted and their use and applicability with regard to haemo- and, histocompatibility, cytotoxicity, genotoxicity and carcinogenesis are discussed.

Reinforcing Linear Low-Density Polyethylene with Surfactant-Treated Microfibrillated Cellulose

Due to its excellent mechanical properties and reinforcement abilities, cellulose has become a promising candidate for developing nanocomposites. However, cellulose agglomeration is an issue that must be solved. In this study, we treated microfibrillated cellulose (MFC) with a mixture of the non-ionic surfactants Span80 and Tween80 (ratio of 1:1) in order to prevent the intermolecular hydrogen bond aggregation of MFC during the process of MFC drying. We used a conical twin-screw extruder to melt compounds for the surfactant-treated MFC and powdered LLDPE. Furthermore, the extruded mixture was hot-pressed into a film, and we also tested the properties of the composite film. We can conclude that there was no agglomeration in the composite film according to microscopic observations and light transmittance test results. Furthermore, the dispersion of the surfactant-treated MFC (STMFC) was uniform until the STMFC filler increased to 10 wt%. The mechanical test results show that when the content of STMFC filler was 10 wt%, the mechanical properties of the composite were optimal. Compared to LLDPE, the STMFC/LLDPE composite film had an increase of 41.03% in tensile strength and an increase of 106.35% in Young's modulus. Under this system, the DSC results show that the melting point of LLDPE increased from 125 to 131 °C. X-ray diffraction (XRD) results showed that the addition of STMFC did not change the crystallinity of the STMFC/LDPE composites, although the crystallite size increased.

Permeability of Ciprofloxacin-Loaded Polymeric Micelles Including Ginsenoside as P-glycoprotein Inhibitor through a Caco-2 Cells Monolayer as an Intestinal Absorption Model

The low oral bioavailability of ciprofloxacin is associated with two distinct challenges: its low aqueous solubility and efflux by p-glycoproteins (P-gp) in the intestinal membrane. Several studies were conducted in order to improve its solubility and permeability through the gastrointestinal membrane. In this study, in a full factorial design study, eight polymeric micelles were prepared and their characteristics, including particle size, loading and release rate were evaluated. Polymeric micelles demonstrated particle sizes below 190 nm and 27⁻88% loading efficiency. Drug release was affected by drug solubility, polymeric micelle erosion and swelling in simulated gastrointestinal fluids. An optimized polymeric micelle was prepared based on appropriate characteristics such as high drug loading and low particle size; and was used for a permeation study on Caco-2 cells. Optimized polymeric micelles with and without ginsenoside and ginsenoside alone enhanced drug permeability through Caco-2 cells significantly in the absorptive direction. The effect of ginsenoside was dose dependent and the maximum effect was seen in 0.23 mg/mL concentration. Results showed that P-gp may not be responsible for ciprofloxacin secretion into the gut. The main mechanism of ciprofloxacin transport through Caco-2 cells in both directions is active diffusion and P-gp has inhibitory effects on ciprofloxacin permeability in the absorptive direction that was blocked by ginsenoside and micelles without ginsenoside.

Effect of silicone oil on the microstructure, gelation and rheological properties of sorbitan monostearate-sesame oil oleogels

Oleogels contain oil or a non-polar liquid which is gelled with an agent called an organogelator. The aim of this study was to evaluate the effects of the addition of silicone oil (cyclopentasiloxane) to the gelation process and to the properties of sorbitan monostearate (SMS)-sesame oil oleogel and compared with that of SMS-sesame oil oleogel and SMS-cyclopentasiloxane oleogel. Three different oil phases; sesame oil phase, cyclopentasiloxane phase and a mixture of cyclopentasiloxane and sesame oil, were used to prepare oleogels with SMS gelator. The critical gelling concentrations (CGC) for oleogels were determined using different concentration of SMS in a range of 5%-22% (w/w). The characterization of the developed oleogels was done using Fourier transform infrared spectroscopy (FTIR), polarized light microscope, rheometer, X-ray diffraction (XRD) and differential scanning calorimetry (DSC). The addition of cyclopentasiloxane reduced the CGC of SMS-sesame oil oleogel from 20% to 10% (w/w). In microscopic characterization, the oleogels with a mixture of oil phases showed the longer and thicker three-dimensional gel network than that of oleogels with sesame oil and cyclopentasiloxane. FTIR studies demonstrated that this network formation was mainly due to hydrogen bonding. Rheological measurements revealed that the combination of cyclopentasiloxane and sesame oil produced strong gel with higher complex modulus values and longer linear viscoelastic region than oleogels prepared with sesame oil and cyclopentasiloxane. In addition, oleogels with the combination of the two oils had higher enthalpy (ΔH _m) and entropy (ΔS _m) thus could increase thermodynamic stability of the oleogels. Therefore, the addition of cyclopentasiloxane can improve the physical, thermal properties and stability of SMS-sesame oil oleogel, provide greater sensory profile and better product aesthetics. The developed oleogel can be a novel carrier for topical drug delivery.

Encapsulation of sorbitan ester-based organogels in alginate microparticles

Leaching of the internal apolar phase from the biopolymeric microparticles during storage is a great concern as it undoes the beneficial effects of encapsulation. In this paper, a novel formulation was prepared by encapsulating the sunflower oil-based organogels in alginate microparticles. Salicylic acid and metronidazole were used as the model drugs. The microparticles were prepared by double emulsion methodology. Physico-chemical characterization of the microparticles was done by microscopy, FTIR, XRD, and DSC studies. Oil leaching studies, biocompatibility, mucoadhesivity, in vitro drug release, and the antimicrobial efficiency of the microparticles were also performed. The microparticles were found to be spherical in shape. Gelation of the sunflower oil prevented leaching of the internal phase from the microparticles. Release of drugs from the microparticles followed Fickian kinetics and non-Fickian kinetics in gastric and intestinal environments, respectively. Microparticles showed good antimicrobial activity against both Gram-positive (Bacillus subtilis) and Gram-negative (Escherichia coli) bacteria. The results suggested that the developed formulations hold promise to carry oils without leakage of the internal phase. Encapsulation of organogels within the microparticles has improved the drug entrapment efficiency and improved characteristics for controlled delivery applications.

Olive oil based novel thermo-reversible emulsion hydrogels for controlled delivery applications

Gels have been considered as a popular mode of delivering medicament for the treatment of sexually transmitted diseases (STDs) (e.g. human immunodeficiency virus, bacterial vaginosis, epididymitis, human papillomavirus infection and condylomata acuminata etc.). The present study discusses the development of novel olive oil based emulsion hydrogels (EHs) using sorbitan monopalmitate as the structuring agent. The developed EHs may be tried as drug delivery vehicle for the treatment of STDs. The formation of EHs was confirmed by fluorescence and confocal microscopy. FTIR studies suggested intermolecular hydrogen bonding amongst the components of the EHs. X-ray diffraction study suggested the amorphous nature of the EHs. The developed EHs have shown non-Newtonian flow behavior. The EHs were found to be biocompatible. The formulations were able to effectively deliver two model antimicrobial drugs (e.g. ciprofloxacin and metronidazole), commonly used in the treatment of the STDs.