Simple Emulsion Research Articles

Development and Evaluation of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) and Polycaprolactone Microparticles of Nimodipine

Polymeric microparticles containing the calcium channel blocker nimodipine were successfully obtained through simple emulsion/ organic solvent evaporating method. The extended release formulations, composed by the polymers poly(3-hydroxybutyrate-co-3- hydroxyvalerate) (PHBV) and polycaprolactone (PCL), were submitted to characterization through X-ray powder diffraction (XRPD), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), thermogravimetric analysis (TG), Fourier transform infrared analysis (FT-IR) and determination of the mean particle diameter. All formulations obtained revealed an amorphous characteristic, proven through XRPD and DSC results. Besides, no chemical interaction was observed between drug and polymer in polymeric microparticles. PHBV-NMP formulation showed a higher drug entrapment, a larger particle size, a thermal degradation behavior similar to that observed for nimodipine and a longer drug release time, being selected for in vivo evaluation. The PHBV-NMP polymeric microparticles were able to keep the pharmacological antihypertensive effect for a longer period of time, becoming a good alternative to control nimodipine release in hypertension treatment.

Sequentially releasing dual-drug-loaded PLGA–casein core/shell nanomedicine: Design, synthesis, biocompatibility and pharmacokinetics

The present study reports an engineered poly-l-lactide-co-glycolic acid (PLGA)–casein polymer–protein hybrid nanocarrier 190±12nm in size entrapping a combination of chemically distinct (hydrophobic/hydrophilic) model drugs. A simple emulsion–precipitation route was adopted to prepare nearly monodispersed nanoparticles with distinct core/shell morphology entrapping paclitaxel (Ptx) in the core and epigallocatechin gallate (EGCG) in the shell, with the intention of providing a sequential and sustained release of these drugs. The idea was that an early release of EGCG would substantially increase the sensitivity of Ptx to cancer, thereby providing improved therapeutics at lower concentrations, with less toxicity. The hemo- and immunocompatibility of the core/shell nanomedicine was established in this study. The core/shell nanoparticles injected via the tail vein in Sprague–Dawley rats did not reveal any organ toxicity as was evident from histopathological evaluations of the major organs. In vivo pharmacokinetic studies in rats by high-performance liquid chromatography confirmed a sustained and sequential release of both the drugs in plasma, indicating prolonged circulation of the nanomedicine and enhanced availability of the drugs when compared to the bare drugs. Overall, the polymer–protein multilayered nanoparticles proved to be a promising platform for nanopolypharmaceutics.

Methods for the preparation of doxycycline-loaded phb micro- and nano-spheres

Natural and synthetic biodegradable polymers have been investigated for controlled drug release. Poly(3-hydroxybutyrate) can be produced by bacteria and is remarkable for this application due to its excellent biocompatibility and biodegradability. The objective of this work was to study different drug-entrapment and emulsification methods for the obtaining of doxycycline-loaded PHB micro- and nano-spheres. The micro-/nano-particles were prepared by polymer precipitation via dialysis, simple emulsion (O/W) or multiple emulsion (W1/O/W2) applying solvent evaporation in the last two cases. This was carried out either by ultrasonication, dripping and/or high speed stirring. Different processing conditions were varied in order to evaluate their influence on morphology, size, and drug entrapment capabilities. The highest drug loading was obtained by single emulsion with high speed stirring. In the case of multiple emulsion, the combination of ultrasound with high speed stirring resulted in the most elevate process yield and drug loading capability.

Formulation and characterization of ethylcellulose microparticles containing .l-alanyl- l-glutamine peptide

Context: The l-alanyl-l-glutamine peptide (AGP) has been effective to promote acute glycemia recovery during long-term insulin-induced hypoglycemia (IIH), and the oral administration of AGP is suggested to prevent prolonged hypoglycemia, such as nocturnal hypoglycemia.Objective: Considering the ability of AGP on glycemia recovery and AGP’s fast metabolism, the aim of current study was to obtain and characterize ethylcellulose microparticles to deliver the drug for a prolonged time.Materials and Methods: Microparticles were prepared by simple and double emulsification/hardening method and characterized by scanning electron microscopy, thermogravimetry (TG), differential scanning calorimetry (DSC), Fourier transform infra-red (FTIR) and FT-Raman spectroscopy and in vitro release.Results and Discussion: Spherical structures with a mean diameter between 9.30 µm and 13.19 µm were formed. TG analysis showed that the thermal stability of AGP was even more increased by encapsulation with ethylcellulose. In addition, TG, DSC, FTIR and FT-Raman analyses proved that AGP was encapsulated in a molecular way. Higher values of encapsulation efficiency were observed for the microparticles prepared by double emulsification (57.83–83.67%) than for those prepared by simple emulsification (18.37%). However, the last ones could release the peptide in a quicker and more extensive manner than those prepared by double emulsification.Conclusion: For the first time, microparticles containing AGP were developed and exhibited prolonged in vitro release as well as protection to the drug, and it could be considered as a dosage form for patients who suffer from insulin-induced hypoglycemia and/or nocturnal hypoglycemia.

PCMs inside emulsions: Some specific aspects related to DSC (differential scanning calorimeter)-like configurations

The heat transfer characteristics during melting of the (phase change material) PCM dispersed inside an emulsion are investigated theoretically and experimentally by using (differential scanning calorimeter) DSC. Genetic algorithm is used to determine the unknown parameters in the physical model. The dispersed PCMs are hexadecane, heptadecane and octadecane. Energy analysis is carried out to understand the thermal behavior of the simple and mixed emulsions. The effect of the heating rate on the thermal behavior of emulsion is also analyzed.

Physicochemical Characterization and in vivo Skin Performance of a Novel Alkyl Polyglucoside Emulsifier in Natural Cosmetic Cream-Bases

Abstract Alkyl polyglucosides (APGs) are a perfect amphiphilic structure, with excellent surface activity and solubility feature. The aim of this study is to develop a simple system, with a relatively low emulsifier content, composed of materials mainly naturally based and with no additional fatty alcohol. Hydroxystearyl alcohol and Hydroxystearyl glucoside, prepared with Jojoba and Hazelnut oil, medium chain triglycerides with or without Xylitylglucoside and Anhydroxylitol and Xylitol, have been investigated by using microscopy, rheology, thermal analysis, pH and conductimetry. Cyclic stress and in vivo skin irritation tests were also conducted. The investigated natural APG emulsifier has a capacity to form simple and stable emulsions of desirable rheological profile with improved hydration potential and to renew damaged skin, thus it can be safely applied as stabilizer in cosmetic and prospective pharmaceutical cream-bases.

Oil-in-water emulsions stabilized by sodium phosphorylated chitosan

Oil-in-water (O/W) emulsions with sodium phosphorylated chitosan (PCTS) were obtained via simple emulsification. PCTS in aqueous solution was amphiphilic with a hydrophilic–lipophilic balance (HLB) of 19 and a critical aggregation concentration (CAC) of 0.13% w/v. The emulsifying efficiency and emulsion stability of PCTS over oil droplets were evaluated in terms of the droplet size, droplet size distribution and microscopic observation using confocal laser scanning microscopy. PCTS preferred to cover oil droplets to produce an O/W emulsion and formed long term stable particles (90 days storage at room temperature) when using PCTS concentrations from above the CAC to 3% w/v. However, emulsions formed from PCTS concentrations below the CAC or over 3% w/v were unstable with particle agglomeration by flocculation after only 7 days storage, although they reverted to individual droplets that retained their integrity in acidic conditions. Overall, PCTS forms effective stable O/W encapsulated particles with potential applications in lipophilic drug encapsulation via a simple emulsion system.

Characterization of Friction Regime with Relaxation Tribometer: First Results on Lubricated Contacts by Simple Fluids and Emulsions

Characterization of Friction Regime with Relaxation Tribometer: First Results on Lubricated Contacts by Simple Fluids and Emulsions

Development and optimization of enteric coated mucoadhesive microspheres of duloxetine hydrochloride using 32full factorial design

Background:Microspheres constitute an important part of oral drug delivery system by virtue of their small size and efficient carrier capacity. However, the success of these microspheres is limited due to their short residence time at the site of absorption.Objective:The objective of the present study was to formulate and systematically evaluate in vitro performance of enteric coated mucoadhesive microspheres of duloxetine hydrochloride (DLX), an acid labile drug.Materials and Methods:DLX microspheres were prepared by simple emulsification phase separation technique using chitosan as carrier and glutaraldehyde as a cross-linking agent. Microspheres prepared were coated with eudragit L-100 using an oil-in-oil solvent evaporation method. Eudragit L-100was used as enteric coating polymer with the aim to release the drug in small intestine The microspheres prepared were characterized by particle size, entrapment efficiency, swelling index (SI), mucoadhesion time, in vitro drug release and surface morphology. A 32 full factorial design was employed to study the effect of independent variables polymer-to-drug ratio (X1) and stirring speed (X2) on dependent variables, particle size, entrapment efficiency, SI, in vitro mucoadhesion and drug release up to 24 h (t24).Results:Microspheres formed were discrete, spherical and free flowing. The microspheres exhibited good mucoadhesive property and also showed high percentage entrapment efficiency. The microspheres were able to sustain the drug release up to 24 h.Conclusion:Thus, the prepared enteric coated mucoadhesive microspheres may prove to be a potential controlled release formulation of DLX for oral administration.

FORMULATION AND CHARACTERIZATION OF CROSS LINK CHITOSAN MICROSPHERE: APPLICATION AS A MUCOADHESIVE DRUG DELIVERY OF NIFEDIPINE

The purpose of this research was to formulate and systematically evaluate in vitro performance of mucoadhesive microspheres of nifedipine. Cross-linking Nifedipine microspheres containing chitosan were prepared by simple emulsification phase separation technique using glutaraldehyde as a cross-linking agent. A simple lattice design was employed to study the effect of independent variables, volume of cross-linking agent (X1), cross-linking time (X2) and total stirring time (X3) on dependent variables percentage mucoadhesion, drug entrapment efficiency and release of nifedipine. Results of preliminary trials indicate that volume of cross-linking agent, time for cross-linking and total stirring time affected characteristics of microspheres. Microspheres were discrete, spherical, and free flowing. The microspheres exhibited good mucoadhesive property in the in vitro wash-off test and also showed high percentage drug entrapment efficiency. From the statistical evaluation, best batch found showed 60.47 % mucoadhesion after 1 hour, 60 % drug entrapment efficacy and desired drug release profile upto 12 hours by taking 3.2 ml of cross-linking agent, 3 hours of crosslinking time and 3.8 hours of total stirring time. This statistically optimized batch was repeated to validate the results.

Macroporous Polymer Beads and Monoliths From Pickering Simple, Double, and Triple Emulsions

AbstractVarious polymeric materials based on simple, double, and triple emulsions stabilized solely by dichlorodimethylsilane (DCDMS)‐modified amorphous silica nanoparticles of well‐controlled surface hydrophobicities or organo‐modified Laponite clay nanoparticles are described. Magnetic and fluorescent polymer beads having different morphologies are fabricated from double‐emulsion templates. Polymer foams based on Pickering emulsions are fabricated and functionalized using different materials such as sporopollenin and zinc metal particles. Suspension polymerization of both oil phases of a novel Pickering triple emulsion results in the formation of new porous hierarchical structures. Polymer foams and beads based on novel nonaqueous Pickering simple and double emulsions are fabricated.

Enhancing saltiness in emulsion based foods

Abstract Background The concept of enhancing saltiness perception in emulsions and a liquid food formulated with the emulsions (ambient vegetable soup) through increasing salt concentration in the continuous phase while retaining the fat content of the (aqueous continuous) product was evaluated. This was accomplished by increasing the droplet phase volume using duplex emulsion technology. Viscosity and droplet size distribution was measured. Saltiness evaluation was based on simple paired comparison testing (2-Alternate Forced Choice tests, BS ISO 5495:2007). Results Single and duplex emulsions and emulsion-based products had comparable mean oil droplet diameters (25 to 30 μm); however, viscosity of the duplex emulsion systems was considerably higher. Sensory assessment of saltiness of emulsion pairs (2AFC) indicated duplex technology enhanced saltiness perception compared to a single emulsion product at the same salt content (6.3 g/100 g) in both simple emulsions and the formulated food product (P = 0.0596 and 0.0004 respectively) although assessors noted the increased viscosity of the duplex systems. The formulated food product also contained pea starch particles which may have aided product mixing with saliva and thus accelerated tastant transport to the taste buds. Lowering salt content in the duplex systems (to levels of aqueous phase salt concentration similar to the level in the single systems) resulted in duplex systems being perceived as less salty than the single system. It appears that the higher viscosity of the duplex systems could not be “overruled” by enhanced mixing through increased droplet phase volume at lowered salt content. Conclusions The results showed that salt reduction may be possible despite the added technology of duplex systems increasing the overall measured viscosity of the product. The changes in viscosity behavior impact mouthfeel, which may be exploitable in addition to the contribution towards salt reduction. With a view to applying this technology to real processed foods, it needs to be tested for the product in question but it should be considered as part of a salt reduction tool box.

Simple, Reversible Emulsion System Switched by pH on the Basis of Chitosan without Any Hydrophobic Modification

Chitosan without hydrophobic modification is not a good emulsifier itself. However, it has a pH-tunable sol-gel transition due to free amino groups along its backbone. In the present work, a simple reversible Pickering emulsion system based on the pH-tunable sol-gel transition of chitosan was developed. At pH > 6.0, as adjusted by NaOH, chitosan was insoluble in water. Chitosan nanoparticles or micrometer-sized floccular precipitates were formed in situ. These chitosan aggregates could adsorb at the interface of oil and water to stabilize the o/w emulsions, so-called Pickering emulsions. At pH < 6.0, as adjusted by HCl, chitosan was soluble in water. Demulsification happened. Four organic solvents (liquid paraffin, n-hexane, toluene, and dichloromethane) were chosen as the oil phase. Reversible emulsions were formed for all four oils. Chitosan-based Pickering emulsions could undergo five cycles of emulsification-demulsification with only a slight increase in the emulsion droplet size. They also had good long-term stability for more than 2 months. Herein, we give an example of chitosan without any hydrophobic modification to act as an effective emulsifier for various oil-water systems. From the results, we have determined that natural polymers with a stimulus-responsive sol-gel transition should be a good particulate emulsifier. The method for in situ formation of pH-responsive Pickering emulsions based on chitosan will open up a new route to the preparation of a wide range of reversible emulsions.

Low temperature synthesis and optical property of ZnS nanotubes

Zinc sulphide (ZnS) nanotubes were synthesised via simple surfactant emulsion template under hydrothermal conditions. X-ray diffraction, scanning electron microscopy and transmission electron microscope were used to characterise the nanotubes. The results indicate that the nanotubes are composed of nanoparticles. The diameters of the nanotubes vary from 300 to 700 nm and lengths range from 1 to 2 µm. In addition, it is found that the reaction time, reaction temperature and cetyltrimethylammonium bromide play key roles in the phase and morphology control of ZnS nanotubes. Furthermore, room temperature photoluminescence was recorded to investigate the optical property of the obtained product. The stable and strong green emission band centred at 513 nm was attributed to some self-activated centres, probably vacancy states or interstitial states related to the peculiar structure.

Forced generation of simple and double emulsions in all-aqueous systems

We report an easy-to-implement method that allows the direct generation of water-in-water (w/w) single emulsions. The method relies on direct perturbation of the pressure that drives the flow of the dispersed phase of the emulsions. The resultant inner jet is induced to break up into droplets due to the growth of the perturbation through Rayleigh-Plateau instability [L. Rayleigh, Proc. R. Soc. London 29, 71–97 (1879)]; this leads to the formation of monodisperse droplets. By implementing this method on a modified microfluidic device, we directly generate water-in-water-in-water (w/w/w) double emulsions with good control over the size and the number of encapsulated droplets. Our approach suggests a route to apply droplet-based microfluidics to completely water-based systems.

Multifunctional Nanocapsules for Simultaneous Encapsulation of Hydrophilic and Hydrophobic Compounds and On-Demand Release

Cocktail therapy by delivering multiple drugs to diseased cells can elicit synergistic therapeutic effects and better modulate the complex cell-signaling network. Besides selection of drug combinations, a difficulty in delivery is how to encapsulate drugs with various solubility into a common vehicle, particularly when both hydrophobic and hydrophilic compounds are involved. Furthermore, it is highly desirable that the drug release profile can be controlled in an on-demand fashion for balanced therapeutic and side effects. On the basis of a simple and scalable double emulsion approach, we report a new class of nanocapsules that can solve these problems simultaneously. Further linking the nanocapsules with peptides targeting cell surface integrins leads to significantly enhanced cell uptake of the nanocapsules. Intracellular drug release triggered by external stimuli has also been achieved without affecting cell viability. Further development of this technology should open exciting opportunities in treating tough diseases such as cancer, cardiovascular diseases, neurological disorders, and infectious diseases.

Microparticles of poly(hydroxybutyrate-co-hydroxyvalerate) loaded with andiroba oil: Preparation and characterization

Poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), a biodegradable polyester, was used in the preparation of polymeric microparticles containing andiroba oil. Andiroba oil, extracted from the seeds of Carapa guianensis, has insecticide and medicinal properties. Microparticles of PHBV were prepared using o/w simple emulsion followed by solvent evaporation. The properties of these microparticles, such as encapsulation efficiency, and morphological aspects were investigated. Several characterization techniques were used: FTIR, XRD, DSC, TGA-DTA, SEM, and particle-size analysis. The efficiency of encapsulation of andiroba oil was determined by UV-spectroscopy. The results confirmed that PHBV microspheres containing andiroba oil were obtained.

Microencapsulation of Dye‐ and Drug‐Loaded Particles for Imaging and Controlled Release of Multiple Drugs

A polymeric microcapsule that can house different drug-loaded particles using a simple emulsion packaging technique is presented. Compared to the neat microparticles, microcapsules simultaneously release multiple drugs in a sustained manner. These microcapsules could provide a means of controlling release of multiple drugs.

Polyethylene glycol-based biocompatible and highly stable superparamagnetic iron oxide nanoclusters for magnetic resonance imaging

We developed a simple emulsion and solvent-evaporation approach for the clustering of iron oxide nanoparticles using a polyethylene glycol (PEG)-based nonionic surfactant, D-alpha-tocopheryl poly(ethylene glycol 1000) succinate (TPGS). To obtain well-constructed clusters of iron oxide nanoparticles (IONPs), the synthetic parameters (the solvent systems and reaction temperature) were investigated. The rate of solvent evaporation is critical to optimise the formation of clusters which were spherical in shape, had a diameter of approximately 97 nm, and were highly stable for storage at room temperature. This greener synthetic approach displays the benefits of high yield and waste reduction compared to previous reports. In addition, IONP clusters of 50 μg mL−1 retained over 84% of the viability of KB cells and the structure of the clusters can be observed by transmission electron microscopy after cellular internalisation. The mechanism of cellular uptake of the IONP clusters was speculated to be via an energy-dependent endocytic pathway because the internalisation was significantly inhibited at 4 °C. These IONP clusters also had higher saturation magnetisation and r2 relaxation (253.85 s−1 mM−1) values and better T2-weighted contrast performance (r2/r1 = 20.5) than commercial Resovist®. The contrast signal for magnetic resonance imaging was efficiently increased by the IONP clusters in vivo, especially in the liver and tumour regions. Iron staining of both tissues confirmed the accumulation of the nanoparticles in both areas. Thus, these clusters, which were prepared with the use of a nonionic polymer surfactant, can potentially serve as efficient contrast agents for magnetic resonance applications.

Esterification of Glucose by Coconut Oil Fatty Acids Using Immobilized CandidarugosaLipaseE.C.3.1.1.3. inCa-alginate Matrix

In this study, the synthesis of fatty acid - carbohydrate esters used glucose (G) and coconut oil fatty acid (FA). The esterification reaction was carried out enzymatically using Candida rugosalipase in organic solvent (n-hexane). Lipase was immobilized on Ca-alginate gel beads withthe optimum condition for immobilization was1 % of Na-alginate, resulting 61.66% immobilization yield. The optimum conditions for esterification using immobilized lipase in Ca-alginate were at 35 o C, the molar ratio 1:60 (G/FA), 16 hours incubation time and 0 g molecular sieve. Characterization of synthesized product with FT-IR showed that product exhibit the absorbtion of ester functional group at 1737 cm -1 , but with thegreater OH groupabsorption peakat3344.57cm -1 indicatedthat the degree ofesterificationwas still low. The synthesized product was then examined by simple emulsion test and was proved to be an emulsifier. Based on theemulsion test, it was known that theproducts ofthe reactionwereglucoseestersthat have propertiesampiphilicas anemulsifiersystem ofoil-in- water emulsion(o/w).