Interaction of Surface Active Drug Promethazine Hydrochloride with Surfactants: Drug Release from Microemulsions

2021 ◽  
Vol 58 (5) ◽  
pp. 371-382
Author(s):  
Manoni Kurtanidze ◽  
Tinatin Butkhuzi ◽  
Irma Tikanadze ◽  
Rusudan Chaladze ◽  
Manuchar Gvaramia ◽  
...  
Keyword(s):  
Active Drug ◽  
Electrical Conductance ◽  
Free Water ◽  
The Body ◽  
Molar Ratio ◽  
Chromatographic Retention ◽  
Ionic Surfactant ◽  
Water Fraction ◽  
Promethazine Hydrochloride ◽  
Surface Active

Abstract The interaction of surface-active drugs with surfactants, used in the simulation of artificial membranes by direct and reversed micelles, mainly determines the transport of drugs in the body and the complex process of the binding to receptors. Besides, the delivery of drugs into the body via microemulsions has been successfully used to reduce the first-pass metabolism. The structure of mixed reverse microemulsions based on the ionic surfactant sodium bis(2-ethylhexyl)sulfosuccinate (AOT) and the cationic surface active drug promethazine hydrochloride (PMT) was studied spectroscopically in the infrared and UV-visible regions, as well as using electrical conductivity and dynamic light scattering. The release profile of PMT from AOT-based microemulsions was studied using cellulose dialysis bags. The introduction of PMT additive into the water pockets of reverse AOT micelles leads to: a) an increase in free water fraction and a decrease in bound water fraction; b) changing the chromatographic retention factors of the model compounds; c) insignificant influence on the values of the binding constant of optical probe o-nitroaniline with the head groups of AOT; d) quenching of water-induced percolation in electrical conductance of reverse AOT microemulsions; e) a slight decrease in the size of water droplets at the same values of the molar ratio of water/surfactant. The release of PMT from the aqueous system obeys Fick’s law of diffusion (n = 0.4852), and the release of PMT from microemulsions is based on non-Fickian or anomalous diffusion.

scholarly journals The Catalytic Oxidation of Formaldehyde by FeOx-MnO2-CeO2 Catalyst: Effect of Iron Modification

Catalysts ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 555
Author(s):  
Yaxin Dong ◽  
Chenguang Su ◽  
Kai Liu ◽  
Haomeng Wang ◽  
Zheng Zheng ◽  
...  
Keyword(s):  
Low Temperatures ◽  
Oxygen Vacancies ◽  
Catalytic Performance ◽  
Active Oxygen ◽  
Molar Ratio ◽  
N2 Adsorption ◽  
Structure Activity ◽  
Iron Modification ◽  
Surface Active ◽  
Catalyst Effect

A series of FeOx-MnO2-CeO2 catalysts were synthesized by the surfactant-templated coprecipitation method and applied for HCHO removal. The influence of Fe/Mn/Ce molar ratio on the catalytic performance was investigated, and the FeOx-MnO2-CeO2 catalyst exhibited excellent catalytic activity, with complete HCHO conversion at low temperatures (40 °C) when the molar ratio of Fe/Mn/Ce was 2/5/5. The catalysts were characterized by N2 adsorption and desorption, XRD, H2-TPR, O2-TPD and XPS techniques to illustrate their structure–activity relationships. The result revealed that the introduction of FeOx into MnO2-CeO2 formed a strong interaction between FeOx-MnO2-CeO2, which facilitated the improved dispersion of MnO2-CeO2, subsequently increasing the surface area and aiding pore development. This promotion effect of Fe enhanced the reducibility and produced abundant surface-active oxygen. In addition, a great number of Oα is beneficial to the intermediate decomposition, whereas the existence of Ce3+ favors the formation of oxygen vacancies on the surface of the catalyst, all of which contributed to HCHO oxidation at low temperatures.

scholarly journals Preparation and Pharmacokinetic Study of Daidzein Long-Circulating Liposomes

2019 ◽  
Vol 14 (1) ◽  
Author(s):  
Qiao Wang ◽  
Wenjin Liu ◽  
Junjun Wang ◽  
Hong Liu ◽  
Yong Chen
Keyword(s):  
Single Dose ◽  
Drug Concentration ◽  
Drug Loading ◽  
Plasma Drug Concentration ◽  
The Body ◽  
Molar Ratio ◽  
Terminal Phase ◽  
Plasma Drug ◽  
Ultrasonic Time ◽  
Time Required

Abstract In this study, daidzein long-circulating liposomes (DLCL) were prepared using the ultrasonication and lipid film-hydration method. The optimized preparation conditions by the orthogonal design was as follows: 55 to 40 for the molar ratio of soybean phosphatidylcholine (SPC) to cholesterol, 1 to 10 for the mass ratio of daidzein to total lipid (SPC and cholesterol) (w:w), the indicated concentration of 5% DSPE-mPEG2000 (w:w), 50 °C for the hydration temperature, and 24 min for the ultrasonic time. Under these conditions, the encapsulation efficiency and drug loading of DLCL were 85.3 ± 3.6% and 8.2 ± 1.4%, respectively. The complete release times of DLCL in the medium of pH 1.2 and pH 6.9 increased by four- and twofold of that of free drugs, respectively. After rats were orally administered, a single dose of daidzein (30 mg/kg) and DLCL (containing equal dose of daidzein), respectively, and the MRT0−t (mean residence time, which is the time required for the elimination of 63.2% of drug in the body), t1/2 (the elimination half-life, which is the time required to halve the plasma drug concentration of the terminal phase), and AUC0−t (the area under the plasma drug concentration-time curve, which represents the total absorption after a single dose and reflects the drug absorption degree) of daidzein in DLCL group, increased by 1.6-, 1.8- and 2.5-fold as compared with those in the free group daidzein. Our results indicated that DLCL could not only reduce the first-pass effect of daidzein to promote its oral absorption, but also prolong its mean resident time to achieve the slow-release effect.

The Sensory Physiology of the Harvest Mite Trombicula Autumnalis Shaw

1950 ◽  
Vol 27 (3) ◽  
pp. 461-494
Author(s):  
B. M. JONES
Keyword(s):  
Light Intensity ◽  
Natural Environment ◽  
Free Water ◽  
The Body ◽  
Quiescent State ◽  
Sensory Physiology ◽  
Linear Gradient ◽  
Dry Air ◽  
Sudden Decrease ◽  
Heated Object

Responses to stimuli Light. In a strong beam of light the harvest mite will move directly towards the source, whereas in a weak light the tracks are at first inclined to be wavy, but as they approach the source the tracks straighten. The mite moves along the bisector of two intersecting lights of equal intensity, and when blinded on one side makes circus movements. When offered a linear gradient of light intensity the mite avoids the darkened portion and moves towards the lightest part of the field. Its movement towards sunlight is a true response to light and not to heat. A sudden decrease of light intensity produces a questing response. Temperature. The sensory perception of heat is poorly developed. The mite is incapable of locating a warm tube or the body of a young live mouse. On touching a heated object it displays a well-defined response to a temperature difference of about 15° C. In a linear or concentric temperature gradient it displays avoiding reactions to low and high temperatures and appears to prefer a range extending from 15 to 26° C. Chemical stimulation. The mite is repelled at a distance of 0.5 cm. from phenol, methyl phthalate, dilute ammonia, xylene and a 3 % solution of glacial acetic acid. Toluene was repugnant at 1.5 cm., whilst a mixture of amyl acetate and water repelled the mite at 5 cm. Complete indifference was shown to the odour of skin, liver, sebum and cerumen, but perspiration induced an avoiding reaction. Humidity. Depletion of the water content influences the response of the mite to humidity. A desiccated mite is active in dry air and inactive in moist air, but a normal individual will settle in either moist or dry air, while avoiding saturated air. The mite requires high humidities for prolonged survival, but avoids free water. Touch. Unfed mites are very sensitive to touch. The extent of stimulation by contact with each other's bodies, which is regarded as high, immobilizes them, and it is primarily responsible for the quiescent state of a cluster of mites. When the stimulation is low, for example, when only the tarsi are in contact with a surface, the mite responds by displaying a high state of activity. A mite lightly touched will immediately quest, a response induced equally by vibrations of the substratum. Clustering The gregarious habit of the mites is primarily a response to the touch of each other's bodies. When the humidity is within the range 95-100% R.H. light will induce the mites to climb up a rod and form a cluster at the tip. Whether or not negative geotaxis also plays a part, it is difficult to say, because the evidence suggested that the mite is independent of gravity. Sense organs There are three types of sensilla: (1) tactile sensilla, both plumose and plain; (2) peg organs; (3) minute sensory rods, principally confined to the first leg. An elliptical lens, a discoid mass of red-pigmented oily substance, and a pronounced dark pigmented cup are conspicuous features of the better developed anterior eye of each ocular area. Identification of the responses Where possible the responses of the mite to various kinds of stimuli have been identified according to a recognized scheme of classification. Behaviour in the natural environment The responses to stimuli which the mite will encounter in the natural environment, and their value with respect to acquiring a host, are discussed.

Uptake of Zinc by the Aquatic Larvae of Simulium ornatipes (Diptera : Nematocera)

1978 ◽  
Vol 29 (3) ◽  
pp. 299 ◽  
Author(s):  
JGT Carter ◽  
WL Nicholas
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Free Water ◽  
Weight Fraction ◽  
The Body ◽  
Ion Concentration ◽  
High Molecular Weight Fraction ◽  
Phosphonic Acids ◽  
Calcium Ion Concentration ◽  
Molecular Weight Fractions

The uptake and loss of zinc by the aquatic larvae of the blackfly S. ornatipes was investigated using radioactive 65Zn. Larvae may absorb significant quantities of zinc from solution, and a substantial proportion remains in the body when larvae are transferred to zinc-free water. Uptake is assisted by metabolism, but an increase of the calcium ion concentration, although reducing toxicity, has no effect on uptake, exchange or the loss of zinc. Larvae may be fractionated into 'cuticle', 'high-' and 'low-molecular-weight' fractions, based on solubility in water and 80% (v/v) ethanol. In the cuticle and high-molecular-weight fractions two 'pools' may be identified by dialysis against Na3EDTA -a pool in which zinc is weakly held and exchanges rapidly with the zinc in solution, and one where zinc is held and exchanges slowly. Exposure time, temperature, and external concentration influence the quantity of zinc entering these pools. Washing the cuticle and high-molecular-weight fractions with a series of buffers suggests that zinc is bound by phenolic groups in the cuticle fraction, and by phosphonic acids in the high-molecular-weight fraction. Sulfhydryl groups did not bind a major portion of the zinc.

Shift in body fluid compartments after dehydration in humans

1988 ◽  
Vol 65 (1) ◽  
pp. 318-324 ◽  
Author(s):  
H. Nose ◽  
G. W. Mack ◽  
X. R. Shi ◽  
E. R. Nadel
Keyword(s):  
Body Fluid ◽  
Extracellular Fluid ◽  
Plasma Osmolality ◽  
Free Water ◽  
Inverse Correlation ◽  
The Body ◽  
Free Water Clearance ◽  
Before And After ◽  
Body Fluid Compartments ◽  
Fluid Compartments

To investigate the influence of [Na+] in sweat on the distribution of body water during dehydration, we studied 10 volunteer subjects who exercised (40% of maximal aerobic power) in the heat [36 degrees C, less than 30% relative humidity (rh)] for 90-110 min to produce a dehydration of 2.3% body wt (delta TW). After dehydration, the subjects rested for 1 h in a thermoneutral environment (28 degrees C, less than 30% rh), after which time the changes in the body fluid compartments were assessed. We measured plasma volume, plasma osmolality, and [Na+], [K+], and [Cl-] in plasma, together with sweat and urine volumes and their ionic concentrations before and after dehydration. The change in the extracellular fluid space (delta ECF) was estimated from chloride distribution and the change in the intracellular fluid space (delta ICF) was calculated by subtracting delta ECF from delta TW. The decrease in the ICF space was correlated with the increase in plasma osmolality (r = -0.74, P less than 0.02). The increase in plasma osmolality was a function of the loss of free water (delta FW), estimated from the equation delta FW = delta TW - (loss of osmotically active substance in sweat and urine)/(control plasma osmolality) (r = -0.79, P less than 0.01). Free water loss, which is analogous to "free water clearance" in renal function, showed a strongly inverse correlation with [Na+] in sweat (r = -0.97, P less than 0.001). Fluid movement out of the ICF space attenuated the decrease in the ECF space.(ABSTRACT TRUNCATED AT 250 WORDS)

General Dispersant Theory

1969 ◽  
Vol 1969 (1) ◽  
pp. 171-177 ◽  
Author(s):  
Gerard P. Canevari
Keyword(s):  
Oil Spills ◽  
The Body ◽  
Specific Factor ◽  
Chemical Agent ◽  
Naturally Occurring ◽  
Surface Active Agents ◽  
Oil In Water ◽  
Scope Of Application ◽  
The Subject ◽  
Surface Active

Abstract Chemical dispersants have a role in the cleanup of oil spills. However, neither dispersion nor any other current technique is a panacea for this purpose. There are situations where dispersants can be used for the benefit of our natural resources; but there are also instances where they should not be used. Similarly, there are conditions under which they are effective, as well as limits where they become ineffective. These aspects of the subject, as well as the mechanism of and basis for dispersing oil slicks, will be discussed. An understanding of the mechanism of dispersency is of prime importance in order to appreciate the behavior and variation in effectiveness of various generic types of surface active agents in promoting oil-in-water dispersions. In this regard, the presence of naturally occurring surfactants in crude oil and their properties are discussed. Even for the same chemical agent, its efficiency can vary due to the influence of many factors such as method of application, degree of mixing, type of oil, temperature of water, amount of circulation in the body of water, etc. Some chemicals can be more sensitive to a specific factor than others. Therefore, an appreciation of mechanism and the effect of environmental and application factors is necessary in order to assess the appropriate scope of application for dispersants as a tool for the handling of oil spills.

scholarly journals Quantitative Assessment of Water Pools by T1p and T2p MRI in Acute Cerebral Ischemia of the Rat

2008 ◽  
Vol 29 (1) ◽  
pp. 206-216 ◽  
Author(s):  
Kimmo T Jokivarsi ◽  
Juha-Pekka Niskanen ◽  
Shalom Michaeli ◽  
Heidi I Gröhn ◽  
Michael Garwood ◽  
...  
Keyword(s):  
Correlation Time ◽  
Continuous Wave ◽  
Vasogenic Edema ◽  
Free Water ◽  
Rotating Frame ◽  
Mri Contrast ◽  
Water Fraction ◽  
Acute Cerebral Ischemia ◽  
Rotating Frame Relaxation

The rotating frame longitudinal relaxation magnetic resonance imaging (MRI) contrast, T1ρ, obtained with on-resonance continuous wave (CW) spin-lock field is a sensitive indicator of tissue changes associated with hyperacute stroke. Here, the rotating frame relaxation concept was extended by acquiring both T1ρ and transverse rotating frame ( T2ρ) MRI data using both CW and adiabatic hyperbolic secant (HSn; n = 1, 4, or 8) pulses in a rat stroke model of middle cerebral artery occlusion. The results show differences in the sensitivity of spinlock T1ρ and T2ρ MRI to detect hyperacute ischemia. The most sensitive techniques were CW- T1ρ and T1ρ using HS4 or HS8 pulses. Fitting a two-pool exchange model to the T1ρ and T2ρ MRI data acquired from the infarcting brain indicated time-dependent increase in free water fraction, decrease in the correlation time of water fraction associated with macromolecules, and increase in the exchange correlation time. These findings are consistent with known pathology in acute stroke, including vasogenic edema, destructive processes, and tissue acidification. Our results show that the sensitivity of the spinlock MRI contrast in vivo can be modified using different spinlock preparation blocks, and that physicochemical models of the rotating frame relaxation may provide insight into progression of ischemia in vivo.

Experimental Study of Biological Material Preparation Based on Optical and Mechanical Dynamics

2014 ◽  
Vol 556-562 ◽  
pp. 366-370
Author(s):  
Jun Mei Wan ◽  
Ming Zhang Ao
Keyword(s):  
Konjac Glucomannan ◽  
The Body ◽  
Molar Ratio ◽  
Human Immune System ◽  
Scientific Analysis ◽  
Human Experiments ◽  
Data Statistics ◽  
Human Immune ◽  
Main Components ◽  
Mechanical Dynamics

The main components of Konjac glucomannan are glucose and glucomannan that are byڂ1-4 bond [ molar ratio is 1.6: (1~4) ] of high molecular weight non-ionic glucomannan, special glucose and mannose's ڂ-1-4chain structure isn't affected by the human digestive enzymes, and does not generate heat. According to the peculiar properties of konjac glucomannan, through the scientific experiment in the body of a rabbit to verify its unique immunological function, and then the human experiments after the effective experimental data statistics scientific analysis, finally the system can obtain the effect of konjac glucomannan on human immune system.

Application of a Boundary Element Method for Wave-Body Interaction Problems Considering the Non-Linear Water Surface

2017 ◽  
Author(s):  
Daniel Ferreira González ◽  
Jonas Bechthold ◽  
Moustafa Abdel-Maksoud
Keyword(s):  
Water Surface ◽  
Three Dimensional ◽  
Free Water ◽  
Numerical Approach ◽  
Panel Method ◽  
The Body ◽  
Time Step ◽  
Non Linear ◽  
Wigley Hull ◽  
Tank Test

In this paper an existing time domain panel method, which was originally developed for propeller flow simulations, is extended by implementing the mixed Eulerian-Lagrangian approach for the computation of the non-linear free water surface. The three-dimensional panel method uses a constant source and doublet density distribution on each panel and a Dirichlet boundary condition to solve the velocity potential in every time step. Additionally, a formulation for the acceleration potential is included in order to determine the hydrodynamic forces accurately. The paper gives an overview on the governing equations and introduces the numerical approach. Validation results of the developed method are presented for the wave resistance of a submerged spheroid and a wigley hull. Additionally, the wave diffraction due to a surface piercing cylinder in regular waves is validated regarding the forces and the water surface elevation around the body. Here, the computations are compared with other numerical methods as well as tank test results. Apart from this, the paper deals with an application example showing simulations of an artificial service vessel catamaran in waves. The forces on the hull with and without forward speed are presented. The paper concludes with a discussion of the presented results and a brief outlook on further work.

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