scholarly journals Water-in-Water Emulsion as a New Approach to Produce Mesalamine-Loaded Xylan-Based Microparticles

2019 ◽  
Vol 9 (17) ◽  
pp. 3519
Author(s):  
Bartolomeu S. Souza ◽  
Henrique R. Marcelino ◽  
Francisco Alexandrino ◽  
Silvana C. C. Urtiga ◽  
Karen C. H. Silva ◽  
...  
Keyword(s):  
Small Molecules ◽  
Drug Loading ◽  
Continuous Phase ◽  
Clinical Use ◽  
Water Emulsion ◽  
New Approach ◽  
Emulsion Method ◽  
Discontinuous Phase ◽  
Rapid Diffusion ◽  
Full Factorial

The water-in-water emulsion method has been reported as a technique able to prepare microparticles without using harmful solvents. However, there are few reports showing the encapsulation of small molecules into microparticles produced within this technique. The probable reason relays on the rapid diffusion of these molecules from the discontinuous phase to the continuous phase. In the present study, xylan microparticles containing mesalamine were produced and the doubled crosslinking approach, used to promote higher encapsulation rates, was disclosed. To achieve this goal, a 23 full factorial design was carried out. The results revealed that all formulations presented spherical-shaped microparticles. However, at specific conditions, only few formulations reached up to 50% of drug loading. In addition, the new xylan-based microparticles formulation retained almost 40% of its drug content after 12 h of a dissolution assay likely due to the degree of crosslinking. Thus, the doubled crosslinking approach used was effective on the encapsulation of mesalamine and may pave the way to successfully produce other polysaccharide-based carriers for clinical use.

Investigating the influence of aromatic moieties on the formulation of hydrophobic natural products and drugs in poly(2-oxazoline) based amphiphiles

2018 ◽  
Author(s):  
Robert Luxenhofer ◽  
Michael M Lübtow ◽  
Lukas Hahn ◽  
Thomas Lorson ◽  
Rainer Schobert
Keyword(s):  
Natural Products ◽  
Small Molecules ◽  
Water Solubility ◽  
Drug Loading ◽  
High Drug ◽  
Long Term Stability ◽  
Aromatic Content ◽  
Important Interaction ◽  
Amorphous Structures ◽  
High Drug Loading

Many natural compounds with interesting biomedical properties share one physicochemical property, namely a low water solubility. Polymer micelles are, among others, a popular means to solubilize hydrophobic compounds. The specific molecular interactions between the polymers and the hydrophobic drugs are diverse and recently it has been discussed that macromolecular engineering can be used to optimize drug loaded micelles. Specifically, π-π stacking between small molecules and polymers has been discussed as an important interaction that can be employed to increase drug loading and formulation stability. Here, we test this hypothesis using four different polymer amphiphiles with varying aromatic content and various natural products that also contain different relative amounts of aromatic moieties. While in the case of paclitaxel, having the lowest relative content of aromatic moieties, the drug loading decreases with increasing relative aromatic amount in the polymer, the drug loading of curcumin, having a much higher relative aromatic content, is increased. Interestingly, the loading using schizandrin A, a dibenzo[a,c]cyclooctadiene lignan with intermediate relative aromatic content is not influenced significantly by the aromatic content of the polymers employed. The very high drug loading, long term stability, the ability to form stable highly loaded binary coformulations in different drug combinations, small sized formulations and amorphous structures in all cases, corroborate earlier reports that poly(2-oxazoline) based micelles exhibit an extraordinarily high drug loading and are promising candidates for further biomedical applications. The presented results underline that the interaction between the polymers and the incorporated small molecules are complex and must be investigated in every specific case.<br>

Click Reactions in Chemistry of Triterpenes - Advances Towards Development of Potential Therapeutics

2018 ◽  
Vol 25 (5) ◽  
pp. 636-658 ◽  
Author(s):  
Jan Pokorny ◽  
Lucie Borkova ◽  
Milan Urban
Keyword(s):  
Biological Activities ◽  
Synthetic Approach ◽  
Clinical Use ◽  
New Approach ◽  
Click Reactions ◽  
Drug Candidates ◽  
The Past ◽  
Low Toxicity ◽  
New Compounds ◽  
Potential Therapeutics

Triterpenoids are natural compounds with a large variety of biological activities such as anticancer, antiviral, antibacterial, antifungal, antiparazitic, antiinflammatory and others. Despite their low toxicity and simple availability from the natural resources, their clinical use is still severely limited by their higher IC50 and worse pharmacological properties than in the currently used therapeutics. This fact encouraged a number of researchers to develop new terpenic derivatives more suitable for the potential clinical use. This review summarizes a new approach to improve both, the activity and ADME-Tox properties by connecting active terpenes to another modifying molecules using click reactions. Within the past few years, this synthetic approach was well explored yielding a lot of great improvements of the parent compounds along with some less successful attempts. A large quantity of the new compounds presented here are superior in both activity and ADME-Tox properties to their parents. This review should serve the researchers who need to promote their hit triterpenic structures towards their clinical use and it is intended as a guide for the chemical synthesis of better drug candidates.

Percolation phase transition of static and growing networks under a weighted function

2016 ◽  
Vol 27 (07) ◽  
pp. 1650082 ◽  
Author(s):  
Xiao Jia ◽  
Jin-Song Hong ◽  
Ya-Chun Gao ◽  
Hong-Chun Yang ◽  
Chun Yang ◽  
...  
Keyword(s):  
Phase Transition ◽  
Continuous Phase ◽  
Weighted Function ◽  
Percolation Process ◽  
Practical Applications ◽  
Network Intervention ◽  
Growing Networks ◽  
Discontinuous Phase ◽  
And Control ◽  
Growing Network

We investigate the percolation phase transitions in both the static and growing networks where the nodes are sampled according to a weighted function with a tunable parameter [Formula: see text]. For the static network, i.e. the number of nodes is constant during the percolation process, the percolation phase transition can evolve from continuous to discontinuous as the value of [Formula: see text] is tuned. Based on the properties of the weighted function, three typical values of [Formula: see text] are analyzed. The model becomes the classical Erdös–Rényi (ER) network model at [Formula: see text]. When [Formula: see text], it is shown that the percolation process generates a weakly discontinuous phase transition where the order parameter exhibits an extremely abrupt transition with a significant jump in large but finite system. For [Formula: see text], the cluster size distribution at the lower pseudo-transition point does not obey the power-law behavior, indicating a strongly discontinuous phase transition. In the case of growing network, in which the collection of nodes is increasing, a smoother continuous phase transition emerges at [Formula: see text], in contrast to the weakly discontinuous phase transition of the static network. At [Formula: see text], on the other hand, probability modulation effect shows that the nature of strongly discontinuous phase transition remains the same with the static network despite the node arrival even in the thermodynamic limit. These percolation properties of the growing networks could provide useful reference for network intervention and control in practical applications in consideration of the increasing size of most actual networks.

Effect of Shear and Water Cut on Phase Inversion and Droplet Size Distribution in Oil–Water Flow

2018 ◽  
Vol 141 (3) ◽  
Author(s):  
Mo Zhang ◽  
Ramin Dabirian ◽  
Ram S. Mohan ◽  
Ovadia Shoham
Keyword(s):  
Size Distribution ◽  
Droplet Size ◽  
Phase Inversion ◽  
Droplet Size Distribution ◽  
Continuous Phase ◽  
Dispersed Phase ◽  
Water Emulsion ◽  
Inversion Region ◽  
Oil Water ◽  
Water Cut

Oil–water dispersed flow occurs commonly in the petroleum industry during the production and transportation of crudes. Phase inversion occurs when the dispersed phase grows into the continuous phase and the continuous phase becomes the dispersed phase caused by changes in the composition, interfacial properties, and other factors. Production equipment, such as pumps and chokes, generates shear in oil–water mixture flow, which has a strong effect on phase inversion phenomena. The objective of this paper is to investigate the effects of shear intensity and water cut (WC) on the phase inversion region and also the droplet size distribution. A state-of-the-art closed-loop two phase (oil–water) flow facility including a multipass gear pump and a differential dielectric sensor (DDS) is used to identify the phase inversion region. Also, the facility utilizes an in-line droplet size analyzer (a high speed camera), to record real-time videos of oil–water emulsion to determine the droplet size distribution. The experimental data for phase inversion confirm that as shear intensity increases, the phase inversion occurs at relatively higher dispersed phase fractions. Also the data show that oil-in-water emulsion requires larger dispersed phase volumetric fraction for phase inversion as compared with that of water-in-oil emulsion under the same shear intensity conditions. Experiments for droplet size distribution confirm that larger droplets are obtained for the water continuous phase, and increasing the dispersed phase volume fraction leads to the creation of larger droplets.

scholarly journals Solid phase synthesis of calcium stearate on a modified screw equipment

2019 ◽  
Vol 58 (4) ◽  
pp. 127-132
Author(s):  
Alexander A. Momziakov ◽  
◽  
Timur R. Deberdeev ◽  
Rustam Ya. Deberdeev ◽  
Eugeny A. Pecheny ◽  
...  
Keyword(s):  
Solid Phase ◽  
Metal Salt ◽  
Mechanical Energy ◽  
Mechanical Action ◽  
Calcium Stearate ◽  
Chemical Additives ◽  
Metal Carboxylates ◽  
New Approach ◽  
Solution Methods ◽  
Full Factorial

Metal stearates are widely used in various industries: as a thickener, lubricants, auxiliary desiccant, emulsifier for cosmetics, chemical additives to synthetic rubbers and a stabilizing component in polyolefins (PE, PP), ABS plastic, polystyrene, polyamide and polyvinyl chloride ( PVC). The greatest interest in using the metal salt of stearic acid is stabilization of PVC. At present, technologies for the synthesis of divalent metal carboxylates have evolved in three directions: synthesis technology in solution, in the melt and in the solid phase. The latter was the most laborious at the end of the last century due to the lack of equipment that allowed the imposition of mechanical energy on the material in sufficient quantity to initiate chemical transformation. In the literature, experiments are carried out on planetary mills, attritors, rollers and Bridgman anvils. In devices of a similar design, the best conditions for the chemical process between the components of the reaction mixture are created. The chemical reaction proceeds as a result of the creation and subsequent relaxation of the stress field when applying a mechanical action to the reaction mixture. However, they did not give a high selectivity for the target product; therefore, the chemical industry of stabilizing additives focused on solution methods for producing metal carboxylates. The authors of the article have developed a new approach for the synthesis of calcium stearate in the solid phase on a modified screw apparatus. Screw machines, in turn, provide an increase in the number of contacts between reagents and, more significantly, the area of the contact interface. In addition, heat generation due to friction in the contact area can further intensify the process. The influence of the temperature range inside the material cylinder - the reactor, the screw rotation speed on the technical characteristics and the yield of calcium stearate was investigated. Mathematical processing of the results of the full factorial experiment was carried out. A comparison of the adequacy of the obtained linear equation and experimental data is carried out.

scholarly journals Plants Extracts Loaded in Nanocarriers: An Emergent Formulating Approach

2018 ◽  
Vol 13 (9) ◽  
pp. 1934578X1801300 ◽  
Author(s):  
Anna Rita Bilia ◽  
Vieri Piazzini ◽  
Martina Asprea ◽  
Laura Risaliti ◽  
Giulia Vanti ◽  
...  
Keyword(s):  
Essential Oils ◽  
Therapeutic Efficacy ◽  
Subcritical Water ◽  
Drug Carrier ◽  
Drug Loading ◽  
The Body ◽  
Clinical Use ◽  
Intrinsic Dissolution ◽  
Optimal Drug ◽  
Increasing Demand

Over the millennia, plants have represented for Humankind the main source of food, but also a vast resource to maintain health, for prophylactic properties or to cure human and animal diseases. Presently, between 65 and 80% of populations in developing countries use medicinal plants as therapeutic remedies for their primary healthcare and in Europe and USA there is an increasing demand of botanical products both on the form of food supplements and herbal medicinal products. Botanicals on the market are mainly based on traditional (infusions or decoctions), conventional (using organic solvents) and innovative (supercritical CO2 or subcritical water) extracts but there is an increasing demand of essential oils for aromatherapy. Conversely, the clinical use of many extracts is limited due to the need of repeated administrations or high doses because of low hydrophilicity and intrinsic dissolution rate(s), or physical/ chemical instability. Other limits are low absorption, poor pharmacokinetics and bioavailability, scarce biodistribution, first pass metabolism, trivial penetration and accumulation in the organs of the body. In the case of essential oils, the high volatility and instability are further limitations. Nowadays, the design and production of appropriate drug delivery systems, in particular nanosized ones (between 50 and 300 nm), have already entered into clinical use and can offer an advanced approach to optimized the therapeutic efficacy of extracts and essential oils. A successful drug carrier system should have optimal drug loading and release properties, a long shelf life, and exert a much higher therapeutic efficacy as well as lower side effects. Polymeric nanoparticles and lipid based-nanocarriers including micelles, vesicles, nanocochleates, micro- and nanoemulsions represent successful examples of extract nanoformulations overcoming these limitations. This review reports on some paradigmatic success stories of extract and EO nanoformulations with remarkable advantages over conventional formulations, which include increase of solubility, stability, permeation and bioavailability, sustained delivery. Paradigmatic examples include formulations of extracts from Vitex agnus-castus, Sylibum marianum, Phyllanthus amarus, Ginkgo biloba, Panax notoginseng, Hypericum perforatum and thyme essential oil.

scholarly journals Recent Progress in Bioconjugation Strategies for Liposome-Mediated Drug Delivery

Molecules ◽  
2020 ◽  
Vol 25 (23) ◽  
pp. 5672
Author(s):  
Bethany Almeida ◽  
Okhil K. Nag ◽  
Katherine E. Rogers ◽  
James B. Delehanty
Keyword(s):  
Drug Delivery ◽  
Recent Progress ◽  
Recent Literature ◽  
Drug Carrier ◽  
Drug Loading ◽  
Drug Action ◽  
Clinical Use ◽  
Liposomal Drug ◽  
Specific Targeting

In nanoparticle (NP)-mediated drug delivery, liposomes are the most widely used drug carrier, and the only NP system currently approved by the FDA for clinical use, owing to their advantageous physicochemical properties and excellent biocompatibility. Recent advances in liposome technology have been focused on bioconjugation strategies to improve drug loading, targeting, and overall efficacy. In this review, we highlight recent literature reports (covering the last five years) focused on bioconjugation strategies for the enhancement of liposome-mediated drug delivery. These advances encompass the improvement of drug loading/incorporation and the specific targeting of liposomes to the site of interest/drug action. We conclude with a section highlighting the role of bioconjugation strategies in liposome systems currently being evaluated for clinical use and a forward-looking discussion of the field of liposomal drug delivery.

scholarly journals Is Independence Necessary for a Discontinuous Phase Transition within the q-Voter Model?

Entropy ◽  
2019 ◽  
Vol 21 (5) ◽  
pp. 521 ◽  
Author(s):  
Angelika Abramiuk ◽  
Jakub Pawłowski ◽  
Katarzyna Sznajd-Weron
Keyword(s):  
Phase Transition ◽  
Phase Transitions ◽  
Continuous Phase ◽  
Voter Model ◽  
Social Response ◽  
Generalized Model ◽  
Independent Variables ◽  
The Social ◽  
Discontinuous Phase ◽  
Independent Behavior

We ask a question about the possibility of a discontinuous phase transition and the related social hysteresis within the q-voter model with anticonformity. Previously, it was claimed that within the q-voter model the social hysteresis can emerge only because of an independent behavior, and for the model with anticonformity only continuous phase transitions are possible. However, this claim was derived from the model, in which the size of the influence group needed for the conformity was the same as the size of the group needed for the anticonformity. Here, we abandon this assumption on the equality of two types of social response and introduce the generalized model, in which the size of the influence group needed for the conformity q c and the size of the influence group needed for the anticonformity q a are independent variables and in general q c ≠ q a . We investigate the model on the complete graph, similarly as it was done for the original q-voter model with anticonformity, and we show that such a generalized model displays both types of phase transitions depending on parameters q c and q a .

scholarly journals A New Approach to Molecular Configuration Applied to Aqueous Pore Transport

1967 ◽  
Vol 50 (11) ◽  
pp. 2565-2578 ◽  
Author(s):  
Andrew H. Soll
Keyword(s):  
Reflection Coefficient ◽  
Small Molecules ◽  
Structural Characteristic ◽  
Statistical Analyses ◽  
Molecular Models ◽  
Significant Relation ◽  
Molecular Configuration ◽  
New Approach

A cylindrical treatment of the configuration of small molecules in solution has been proposed. Cylindrical dimensions were obtained from Fisher-Hirschfelder molecular models, and these dimensions were used in an analysis of three sets of reflection coefficient values from the literature. The correlation between solute dimensions and the reflection coefficient was subjected to both statistical analyses and graphical examination, with particular emphasis given to parameter interdependence. The results consistently indicated a significant relation between the reflection coefficient and solute diameter. The dependence on diameter suggests a lengthwise orientation of solute within the membrane. Furthermore it is shown that this orientation is occurring within the aqueous region of the membrane, and thus this region has a structural characteristic which is responsible for the lengthwise orientation of solute.

Preparation of porous alumina microspheres via an oil-in-water emulsion method accompanied by a sol–gel process

2016 ◽  
Vol 40 (1) ◽  
pp. 589-595 ◽  
Author(s):  
Hui Yang ◽  
Yuan Xie ◽  
Guisong Hao ◽  
Weiwei Cai ◽  
Xingzhong Guo
Keyword(s):  
Porous Alumina ◽  
Sol Gel ◽  
Three Dimensional ◽  
Water Emulsion ◽  
Emulsion Method ◽  
Oil In Water ◽  
Sol Gel Process ◽  
Template Free ◽  
Oil In Water Emulsion ◽  
Interconnected Structure

Porous alumina microspheres prepared via a facile template-free approach followed by heat-treatment, exhibiting a three-dimensional interconnected structure.

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