Vesicular Dispersions Research Articles

Formulation and Evaluation of Antimicrobial Potential of Glycerosomes Containing Allium sativum, Zingiber officinale Extracts

The aim of the present investigation is to evaluate the antimicrobial potential of A. sativum and Z. officinalis extracts mediated glycerosomes formulation by thin film of lipid hydration method. The water content present in the A. sativum and Z. officinale was 42.3 and 27.2 % respectively. The yield of A. sativum and Z. officinale extract using ethanol as solvent through the Soxhlation process was found to be 4.7 ± 1.05 and 12.7 ± 1.108 % respectively. The crude drug of A. sativum and Z. officinale showed foreign organic was found to be 0.2 and 0.21 % and volatile oil was found to be 1.8 and 2.4 % only. The ash study revealed that total, acid-insoluble, water-soluble, and sulfated ash values were for the crude drugs of A. sativum and Z. officinale. The ethanol extracts showed maximum extractive yield. The phytochemicals detected in A. sativum bulb ethanol extract are Alkaloids, Carbohydrates, Cardiac glycosides, Phenols, Sterols, Triterpenoids, Saponins, Flavonoids, and Fixed oils and in Z. officinale rhizome ethanol extract are Alkaloids, Carbohydrates, Cardiac glycosides, Anthraquinone glycosides, Proteins and Amino acids, Triterpenoids, Saponins, Flavonoid, and Fixed oils. The prepared glycerosome was spherical with a slightly irregular shape. The negative potential of glycerosomes demonstrates the greater stability of the vesicular dispersion. The ASEE glycerosome formulations (F1 and F2) exhibited better antibacterial activity and greater antifungal activity against the gram-negative bacteria in comparison with the ZOEE glycerosome formulations (F3 and F4). The present research work strongly concluded that the A. sativum and Z. officinale and their glycerosome formulations are good candidate drugs and formulations for the safe and effective treatment of microbial infections

Ferric heme b in aqueous micellar and vesicular systems: state-of-the-art and challenges.

Ferric heme b (= ferric protoporphyrin IX = hemin) is an important prosthetic group of different types of enzymes, including the intensively investigated and widely applied horseradish peroxidase (HRP). In HRP, hemin is present in monomeric form in a hydrophobic pocket containing among other amino acid side chains the two imidazoyl groups of His170 and His42. Both amino acids are important for the peroxidase activity of HRP as an axial ligand of hemin (proximal His170) and as an acid/base catalyst (distal His42). A key feature of the peroxidase mechanism of HRP is the initial formation of compound I under heterolytic cleavage of added hydrogen peroxide as a terminal oxidant. Investigations of free hemin dispersed in aqueous solution showed that different types of hemin dimers can form, depending on the experimental conditions, possibly resulting in hemin crystallization. Although it has been recognized already in the 1970s that hemin aggregation can be prevented in aqueous solution by using micelle-forming amphiphiles, it remains a challenge to prepare hemin-containing micellar and vesicular systems with peroxidase-like activities. Such systems are of interest as cheap HRP-mimicking catalysts for analytical and synthetic applications. Some of the key concepts on which research in this fascinating and interdisciplinary field is based are summarized, along with major accomplishments and possible directions for further improvement. A systematic analysis of the physico-chemical properties of hemin in aqueous micellar solutions and vesicular dispersions must be combined with a reliable evaluation of its catalytic activity. Future studies should show how well the molecular complexity around hemin in HRP can be mimicked by using micelles or vesicles. Because of the importance of heme b in virtually all biological systems and the fact that porphyrins and hemes can be obtained under potentially prebiotic conditions, ideas exist about the possible role of heme-containing micellar and vesicular systems in prebiotic times.

Effects of the Method of Preparation and Dispersion Media on the Optical Properties and Particle Sizes of Aqueous Dispersions of a Double-Chain Cationic Surfactant.

As inferred from visual observations and turbidity measurements, the average radius of the unilamellar vesicles formed in water from the cationic double-chain surfactant didodecyldimethylammonium bromide (DDAB) varies with the method of preparation, being ∼24 nm after sonication (SS method) and ∼74 nm after extrusion/ultrafiltration (SE method). The radii were larger when the vesicles were produced in 10 mM NaBr, ∼65 nm for the SS method and ∼280 nm for the SE method. The specific turbidity, or turbidity per unit path length divided by the surfactant weight fraction, w, of these vesicular dispersions increased with decreasing w until a constant value was reached at w*, which depends on the preparation method and the dispersion medium. The constant specific turbidities are indicative of single and independent scattering and were used to estimate vesicle radii by solving the specific turbidity equations derived for the Rayleigh-Debye-Gans (RDG) regime. Two turbidity equations were used, one accounting for absorbance errors due to some scattered light reaching the detector and another with no correction. Estimates of the average distances between the vesicles and their corresponding Debye lengths were obtained for evaluating the importance of intervesicle electrostatic interactions, which could lead to dependent scattering at higher weight fractions.

Curved Lipid Interfaces Studied with Grazing Incident SANS

Curved cell membranes are important for the function of the cell, both for compartmentalization in organelles within the cell, as well as for cellular mitosis. It has also been shown that the curvature of a lipid membrane can affect the concentration of membrane bound proteins. In this project we have used semiconductor nanowires in order to study the effect of curvature on phospholipid bilayers and membrane proteins. We have previously demonstrated the formation of a supported phospholipid bilayer on nano wires via vesicle fusion, which can be used as a proxy to curved membranes. Based on fluorescence recovery after photobleaching, FRAP, measurement, the phospholipid bilayers were found to follow the contours of the nano wires as continuous and fluid, locally curved bilayers. However these data do not reveal the coverage, composition and the dimensions of the bilayer. In this project we aim to revel this using grazing incident small angle neutron scattering (GISANS). For this purpose we have performed GISANS experiments at the KSW-1 at FRM II (Germany), VSANS at NIST (USA) and SANS2D at ISIS (UK) with phospholipid covered nanowires. The nanowires were covered with a phospholipid bilayer obtained from deposition from vesicular dispersion of mixture of 20mol% DOPE in DOPC. In these experiments we have successfully shown the formation of a lipid bilayer and the subsequent binding of membrane protein. These results shows that nanowire supported lipid bilayer is an excellent way to study biding membrane protein to curved lipid interfaces.

DoE directed optimization, development and evaluation of resveratrol loaded ultradeformable vesicular cream for topical antioxidant benefits

Objective: Aim of the present work was to optimize and formulate resveratrol loaded vesicular cream intended for dermal delivery of resveratrol with high skin deposition potential.Methods: Formulation was developed and optimized using Central Composite Design. Amount of phospholipid and sodium cholate were selected as critical material attributes and vesicle size and entrapment efficiency of resveratrol were taken as critical quality attributes. To increase the skin applicability and patient compliance, vesicles were further developed as vesicular cream which was then thoroughly characterized for physicochemical parameters, ex vivo skin permeation/deposition profile and antioxidant potential.Results: Vesicle size and entrapment efficiency of the optimized batch were found to be 178.9 ± 12.87 nm with 72.32 ± 3.45% respectively. Physicochemical properties and viscosity of cream formulation were also found to be favorable for skin applicability. Permeation flux at the end of 24 h was found to be 2.70 ± 0.73, 4.45 ± 0.56 and 4.95 ± 0.69 µg cm−2 h−1 for conventional cream, vesicular dispersion, and vesicular cream formulation respectively. Higher drug deposition in the skin via vesicular cream formulation was observed i.e. 335.2 ± 4.12 µg cm−2 (70.16 ± 0.87%) as compared to conventional cream i.e. 67.12 ± 19.63 µg cm−2 (14.05 ± 4.11%). Resveratrol encapsulated in vesicular cream has retained its inherent antioxidant activity suggesting the stability of resveratrol in vesicular cream.Conclusion: Thus, it can be concluded that deformable vesicular cream is capable of delivering encapsulated bioactive in deeper layers of skin, where it can be retained for achieving higher dermatological benefits.

Consolidated bile-based vesicles/self-nanoemulsifying system (CBBVs/SNES) as a solution for limitations of oral delivery of vesicular dispersions: In-vitro optimization and elucidation of ex-vivo intestinal transport mechanisms

The oral delivery of bile-based vesicles (BBVs) has been limited by their poor physical stability, low drug load and slow absorption rate. The novel consolidated bile-based vesicles/self-nanoemulsifying system (CBBVs/SNES) combines the advantages of vesicular and self-nanoemulsifying systems (SNES). This work aimed to prepare physically stable CBBVs/SNES loaded with the full dose of amlodipine besylate (AB) as model drug. AB-loaded BBVs dispersion was optimized using Box-Behnken design and evaluated for particle size distribution, encapsulation efficiency and solubilization efficiency. AB-loaded CBBVs/SNES was prepared by mixing the vesicles of the optimized BBV with Labrafil-based SNES that gave the highest drug solubility. AB-loaded CBBVs/SNES was evaluated for particle size, Polydispersity index (PDI) and in vitro release. When diluted in GIT fluids, consolidated system spontaneously emulsifies forming nanosized oil droplets and in-situ formed mixed micelles. The formation of nanosized mixed micelles (<100 nm) was confirmed by transmission electron microscopy and particle size analysis (PS; 106.8 ± 17.60 nm and PDI; 0.20 ± 0.01). The developed CBBVs/SNES showed enhanced physical stability when stored for 3 months at 2–8 °C. The ex-vivo transport study confirmed that the developed CBBVs/SNES improved the drug transport about 3.8 folds in comparison to the reconstituted vesicular dispersion through offering three pathways of transport (in-situ formed mixed micelles uptake, nanoemulsion droplet uptake and vesicular uptake). The various offered transport pathways and the improvement of drug load and physical stability propose that CBBVs/SNES administered via the oral route could therefore be promising in oral delivery of vesicular systems. In-vivo studies is presently investigated.

Design by optimization and comparative evaluation of vesicular gels of etodolac for transdermal delivery

Aim of the present study was to design vesicular gels of etodolac loaded liposomes and ethosomes for effective transdermal delivery. The physicochemical properties of vesicular gels were compared with 45% v/v ethanolic etodolac solution and commercial product (PROXYM®). The liposomes were prepared by film hydration technique whereas ethosomes were prepared by cold method respectively. Both the systems were characterized for various physicochemical properties. The size range of liposomes shows 186 nm–363 nm whereas for ethosomes 170 nm–261 nm respectively. The zeta potential of optimized liposomes and ethosomes was found to be −36.5 mV and −48.3 mV, respectively. The highest %EE of liposomes and ethosomes shows 71.5% and 78.5%, respectively. The permeation of liposomes shows in the range of 67.50%–86.06% whereas ethosomes shows 52.30%–99.49%, respectively. The optimization was done by 32 experimental design. The optimized vesicular dispersions were subjected to gel preparation using carbopol 940 NF. The prepared liposomal gel (ETO-LG) and ethosomal gel (ETO-EG) were optimized and characterized. The vesicular gels showed desirable results compared to other test formulations.

Effects of Light Dispersed Particles on the Stability of Dense Suspended Particles Against Sedimentation.

A novel method in which vesicular dispersions of the double-chain cationic surfactant DDAB (didodecyldimethylammonium bromide) stabilize suspensions of high density titania particles was recently presented (Yang, Y.-J; Corti, D.S.; Franses, E. I. Langmuir 2015, 31, 8802-8808). At high enough DDAB concentration, the vesicles form a close-packed structure, providing strong resistance to the sedimentation of the titania particles, while the dispersions remain highly shear-thinning with moderate limiting viscosities. Here, to elucidate the key factors of the mechanism by which vesicles or other nonsettling particles stabilize high density particles against sedimentation, we use Brownian dynamics simulations (BDS) to examine the sedimentation behavior of mixtures of "dense particles" that settle rapidly on their own and "light particles" that represent nonsettling "rigid vesicles". BDS confirm that for large enough values of the volume fraction ϕ2 of the light particles, the dense particles should remain suspended. The rheological behavior of the mixtures is also computed with BDS. The observed shear-thinning behavior of the light particle dispersion suggests that the suspensions of the dense particles are still flowable at high shear stresses. Furthermore, the local viscosity of light particles around the dense particles significantly increases with increasing ϕ2, particularly when the same gravitational force applied in the BDS is exerted on a dense particle. The arrangement of light particles around the moving dense particles is an important factor in determining the stability of the dense particles against sedimentation. The BDS results indicate that dispersions of nonsettling particles provide a general method for the stabilization against sedimentation of high density particles.

The Impact of Nonequilibrium Conditions in Lung Surfactant: Structure and Composition Gradients in Multilamellar Films.

The lipid–protein mixture that covers the lung alveoli, lung surfactant, ensures mechanical robustness and controls gas transport during breathing. Lung surfactant is located at an interface between water-rich tissue and humid, but not fully saturated, air. The resulting humidity difference places the lung surfactant film out of thermodynamic equilibrium, which triggers the buildup of a water gradient. Here, we present a millifluidic method to assemble multilamellar interfacial films from vesicular dispersions of a clinical lung surfactant extract used in replacement therapy. Using small-angle X-ray scattering, infrared, Raman, and optical microscopies, we show that the interfacial film consists of several coexisting lamellar phases displaying a substantial variation in water swelling. This complex phase behavior contrasts to observations made under equilibrium conditions. We demonstrate that this disparity stems from additional lipid and protein gradients originating from differences in their transport properties. Supplementing the extract with cholesterol, to levels similar to the endogenous lung surfactant, dispels this complexity. We observed a homogeneous multilayer structure consisting of a single lamellar phase exhibiting negligible variations in swelling in the water gradient. Our results demonstrate the necessity of considering nonequilibrium thermodynamic conditions to study the structure of lung surfactant multilayer films, which is not accessible in bulk or monolayer studies. Our reconstitution methodology also opens avenues for lung surfactant pharmaceuticals and the understanding of composition, structure, and property relationships at biological air–liquid interfaces.

Experimental Determination of High-Order Bending Elastic Constants of Lipid Bilayers.

We present a method to describe the formation of small lipid vesicles in terms of three bending elastic constants that can be experimentally measured. Our method combines a general expression of the elastic free energy of the bilayer and the thermodynamic description of molecular aggregation. The resulting model requires the size distribution of liposomes, which is determined from the X-ray scattered intensity spectra of vesicular dispersions. By using two different preparation methods, we studied a series of vesicular solutions made of distinct lipids and we obtained their corresponding bending elastic constants that are consistent with known bending rigidities.

Cryogenic transmission electron microscopy study: preparation of vesicular dispersions by quenching microemulsions.

We previously showed that long-lived nanoemulsions, seeming initially vesicular, might be prepared simply by diluting and cooling (quenching) warm microemulsions with n-hexadecane with precooled water. In this paper, we confirm that these systems are vesicular dispersions when fresh, and they can be made with similar structures and compositional dependence using alkanes with chain lengths ranging from octane to hexadecane. The nanostructures of fresh nanoemulsions are imaged with cryogenic transmission electron microscopy (cryo-TEM). We confirm that water-continuous microemulsions give simple dispersions of vesicles (sometimes unilamellar), typically less than 100 nm in diameter; these systems can avoid separation for over 2 months. Selected samples were also prepared using halogenated alkanes to create additional contrast in the cryo-TEM, allowing us to confirm that the oil is located in the observed vesicular structures.

On the Formation of Lipid Nano-Scale Structures at Interfaces Beyond Planar Bilayers

Biological membranes do not only occur as planar bilayer structures, but bilayers have also been shown to, depending on the lipid composition, curve into intriguing 3D structures. Understanding the biological implication as well as the application of such interfaces, for e.g. drug delivery and other biomedical application, requires the development of well-defined model system.Here we demonstrate the formation of fluid supported bilayers on vertical gallium phosphide nanowire (NW) forests using self-assembly from lipid vesicular dispersions (1-2). The phospholipid mixture used had a composition that facilitates the formation of curved bilayers. By applying fluorescence recovery after photobleaching, we determined that the lipids are able to diffuse laterally within the NW-supported bilayer and that the bilayers were found to follow the contours of the nanowires to form continuous and locally highly curved model membranes. Membrane-anchoring proteins as well as tethered vesicles were found to be able to bind to these bilayers on the nanowire substrate.(1) Dabkowska, A.P., Niman, C.S., Piret, G., Persson, H., Wacklin, H.P., Linke, H., Prinz, C.N. & Nylander, T. Fluid and highly curved model membranes on vertical nanowire arrays. Nano Letters, 2014, 14, 4286-4292.(2) Dabkowska, A. P., Piret, G., Niman, C. S., Lard, M., Linke, H., Nylander, T., Prinz, C., N.: Surface nanostructures for fluorescence probing of supported lipid bilayers on reflective substrates. 2015, Accepted in Nanoscale

Use of Close-Packed Vesicular Dispersions to Stabilize Colloidal Particle Dispersions against Sedimentation.

For many applications of colloidal dispersions, the particles must be suspended for a long time. This is often accomplished by preventing agglomeration, which generates aggregates of increasing size. Nevertheless, many colloidal dispersions of dense particles may settle even without agglomeration. Preventing sedimentation without significantly increasing the bulk dispersion viscosity is difficult and has received little attention in the literature. However, settling can be drastically reduced through the novel use of close-packed vesicular dispersions at high enough concentrations, which are non-Newtonian shear-thinning fluids. Such dispersions have much higher viscosities at the low shear stresses "felt" by sedimenting colloidal particles than at the high shear stresses relevant to bulk dispersion flow. In a practical example, dense TiO2 nanoparticles which normally would settle rapidly can remain suspended for at least 6 months without any observable sedimentation when they are introduced into a close-packed vesicular dispersion, while the dispersion retains its flowability. Cryo-TEM images reveal that the vesicles in these dispersions are tightly close-packed. Dynamic light scattering and electrophoretic mobility data also confirm that the vesicles in such dispersions have very low mobilities.

Topical Delivery System for Phytochemicals: Capsaicin and Capsicum Tincture

Capsaicin, an active ingredient of Capsicum fruit, is currently undergoing “revival” in the clinical management of pain. However, the choice of its formulation is rather limited to the use of “old-fashioned” tinctures and recently the patches. In an attempt to improve the therapeutic outcome and develop its skin-friendly formulation, we prepared the vesicle-based drug delivery system with capsaicin. Moreover, the use of standardized Capsicum extract, rather than a single active ingredient, is proposed to lead to simplified and more cost-effective formulations. Phospholipid-based vesicles, namely liposomes and ethosomes, were prepared with capsaicin, Capsicum tincture or Capsicum powder and characterized for particle size, entrapment efficiency and stability. The vesicular dispersions were incorporated in the hydrogels to increase the formulation stability, its retention time at the skin and overall acceptability. Both the standardized crude Capsicum powder and Capsicum tincture were successfully employed as sources of capsaicin which is, to the best of our knowledge, reported for the first time. The reported phospholipid-based delivery system for capsaicin could represent an improved topical treatment of arthritic pain.

Oleic acid vesicles: a new approach for topical delivery of antifungal agent

The occurrence of topical fungal infections is increasing nowadays. Cutaneous fungal infections like cutaneous candidiasis are more prominent in patients associated with AIDS. Current available strategies for the treatment of cutaneous fungal infections are creams or gels which show various adverse effects on skin along with systemic absorption. These drawbacks can be overcome by using various novel drug delivery systems. So, the present investigation aims at exploring the potential of fatty acid vesicles (ufasomes) for the topical delivery of clotrimazole. Oleic acid was employed as a fatty material for the preparation of vesicles. Clotrimazole-loaded oleic acid vesicles were prepared using a thin film hydration method. Prepared vesicles were characterized for size, size distribution, shape, thermal behaviour (differential scanning calorimetry), in vitro release, in vitro antifungal activity, in vitro skin permeation and retention studies and for in vivo antifungal activity. Transmission electron microscopic (TEM) images confirmed the formation of vesicular dispersion (ufasomes) of clotrimazole. Oleic acid vesicles possessed high drug entrapment (49.5 ± 1.0%) and optimum size (455 ± 22 nm) along with good colloidal characteristics (polydispersity index = 0.210 ± 0.035 & zeta potential = − 22.45 ± 0.25 mV) at 4:6 drug-to-oleic acid ratio. In vitro drug release study showed sustained release of drug from the vesicular dispersion. Skin permeation and skin retention studies suggested accumulation of drug in the epidermal part of the skin. In vivo study confirmed prolonged release of drug from oleic acid vesicle up to five days indicating its usefulness for long-term therapy. So, it can be concluded from the present study that fatty acid vesicle may be a good approach to treat topical fungal infections.

Determination of the sorption and desorption kinetics of perfume raw materials in the liquid phase with vesicular dispersion: Application of SIFT-MS

Perfume raw materials such as coumarin, hexyl acetate and octanal are used in domestic fabric softeners together with cationic quaternary ammonium surfactants during the last rinsing step of a wash cycle. Selected ion flow tube mass spectrometry (SIFT-MS) is used to analyze the gas phase concentration of these perfume raw materials in an experiment, mimicking this rinsing step when fabric softeners are applied together with a vesicular diethyl ester dimethyl ammonium chloride (DEEDMAC) dispersion in a bubble column. A continuous stirred tank reactor (CSTR) model is proposed to obtain sorption and desorption kinetics for the mass transfer between the liquid phase and the vesicular dispersion from experimental gas phase concentration data. Sorption coefficients of (4.8±0.3) 10−3, (9.4±0.1) 10−3 and (4.0±0.1) 10−3s−1 are obtained for coumarin, hexyl acetate and octanal. Desorption coefficients for these components are respectively reported as (5.4±0.6) 10−5, (1.8±0.1) 10−5 and (3.5±0.2) 10−5s−1. From an engineering point of view, SIFT-MS is considered to be a promising experimental technique to evaluate the dynamic behavior, i.e., the sorption and desorption kinetics, of molecules in a vesicular dispersion using the proposed CSTR model.

NMR Investigation of Exchange Dynamics and Binding of Phenol and Phenolate in DODAC Vesicular Dispersions

The interaction between phenol molecules, both in their undissociated and dissociated states, and cationic dioctadecyl dimethylammonium chloride (DODAC) vesicles were thoroughly investigated using NMR techniques. In particular, diffusion and relaxation measurements, combined with the two sites Kärger model, were used to evaluate the exchange dynamics and the binding of the aromatic molecules to the vesicles. The results reveal that, besides concentration and vesicle preparation method, pH conditions have the biggest impact on the phenol sorption behavior. Although the dissociated form of phenol formed at high pH is more hydrophilic, the results indicated that phenol-DODAC interactions were largely favored in basic conditions as a consequence of the strong electrostatic interaction between the phenolate anions and the cationic surfactant headgroup.

Polyoxyethylene cholesteryl ether-based aqueous wormlike micelles

Formation of wormlike micelles (WLMs) in an aqueous mixture of polyoxyethylene cholesteryl ether (ChEOn; where n = 20 and 30) and polyoxyethylene dodecyl ether (C12EOm; where m = 3 and 4) has been reported; rheological and small angle X-ray scattering (SAXS) measurements have been performed in the micellar solutions of ChEOn as a function of C12EOm for the structural elucidation. When lipophilic cosurfactant, C12EOm is added to the micellar solutions of ChEOn, it favors the sphere-to-cylinder transition due to the penetration of C12EOm in the palisade layer of ChEOn micelle accompanying an increase in viscosity. When the concentration of C12EOm is increased, entangled network of WLMs is formed. A strong shear thinning has been observed in highly viscous samples indicating the presence of transient networks. Such samples exhibited viscoelastic behavior and could be described by the Maxwell model with a single stress relaxation mode. A maximum is observed in zero-shear viscosity-C12EOm plot. With further addition of C12EOm, viscosity declines and ultimately a phase separation occurs with the formation of turbid solution of vesicular dispersion. This decline has been interpreted in terms of micellar branching induced by an increase in endcap energy, E c (which is compensated by the formation of branch points, having a mean curvature opposite to that of endcaps). The C12EOm induced one-dimensional micellar growth has been confirmed by SAXS.

Novel diphenyl dimethyl bicarboxylate provesicular powders with enhanced hepatocurative activity: Preparation, optimization, in vitro/in vivo evaluation

Diphenyl dimethyl bicarboxylate (DDB) is a hepatocurative agent used for treatment of various liver diseases. However, DDB therapeutic effectiveness is restricted by its low oral bioavailability that arises from its poor solubility and dissolution. Aiming at surmounting the aforementioned restrictions, DDB provesicular dry powders exemplified by proniosomes and proliposomes were prepared using film-deposition technique employing sorbitol as a carrier. Upon dilution with water, the provesicular powders rapidly transformed into vesicular dispersions, either liposomes or niosomes, which were characterized regarding their percent encapsulation efficiency (EE%), vesicle size and distribution, morphology and in vitro drug release. The revealed optimal provesicular powder was exposed to solid state characterization, stability testing and in vivo performance evaluation. Results showed that provesicular powders with acceptable flowability can be prepared using a weight ratio of lipids mixture to sorbitol of 1:20. Proniosomal powder composed of Tween 80:cholesterol:stearylamine in molar ratio 7:3:0.5 loaded on sorbitol was selected as the optimal formulation as it showed the highest EE% and dissolution enhancement for DDB. The elevated levels of liver enzymes in hepatically injured Albino Wister rats were significantly reduced ( P < 0.05) after oral administration of the optimal proniosomal powder in comparison to free DDB. This improvement was confirmed histopathologically by minimizing the associated hepatic injury. Accordingly, proniosomes can be assertively considered as a promising stable precursor for immediate preparation of niosomal carrier for DDB with enhanced dissolution and hepatocurative activity.

Characterization and Aggregation Behaviors of Mixed DDAB/SDS Solution With and Without Poly(4-styrenesulfonic Acid-Co-Maleic Acid) Sodium

Synthetic vesicles are formed by cationic and anionic surfactants, didodecyldimethylammonium bromide (DDAB), and sodium dodecylsulfate (SDS). The morphology, size, and aqueous properties of cationic/anionic mixtures are investigated at various molar ratios between cationic and anionic surfactants. The charged vesicular dispersions made of DDAB/SDS are contacted or mixed with negatively charged polyelectrolyte, poly(4-styrenesulfonic acid-co-maleic acid) sodium (PSSAMA), to form complexes. Depending on DDAB/SDS molar ratio or PSSAMA/vesicle charge ratio, complexes flocculation or precipitation occur. Characterization of the cationic/anionic vesicles or complexes formed by the catanionic vesicles and polyelectrolytes is performed by transmission electron microscope (TEM), dynamic light scattering (DLS), conductivity, turbidity, and zeta potential measurements. The size, stability, and the surface charge on the mixed cationic/anionic vesicles or complexes are determined.