Adsorption-desorption of sotalol hydrochloride by Na-montmorillonite

Clay Minerals ◽  
1987 ◽  
Vol 22 (2) ◽  
pp. 121-128 ◽  
Author(s):  
M. Sánchez-Camazano ◽  
M. J. Sánchez-Martín ◽  
M. T. Vicente ◽  
A. Dominguez-Gil
Keyword(s):  
Ir Spectroscopy ◽  
Salt Concentration ◽  
Interlayer Space ◽  
Elimination Rate ◽  
Exchange Capacity ◽  
Maximum Amount ◽  
Organic Cations ◽  
Dipole Interactions ◽  
Adsorption Desorption

AbstractThe interaction of montmorillonite with sotalol hydrochloride (4-(1-hydroxy-N-isopropylaminoethyl) methane sulfanilide) was studied by means of adsorption isotherms, XRD and IR spectroscopy. The amount of sotalol adsorbed depended on pH, the maximum amount adsorbed (0·56 mEq g−1) being considerably less than the exchange capacity of the mineral (0·80 mEq g−1). XRD and IR data revealed that the sotalol is adsorbed into the interlayer space, forming a monolayer complex with a d001 spacing of 17·7 Å, and that the mechanisms involved are cation exchange and ion-dipole interactions. Experiments on the in vitro desorption of the drug from the sotalol-montmorillonite complex indicated that desorption is affected by pH, by the salt concentration of the electrolyte, and by the elimination rate of the desorbed organic cations.

scholarly journals Pharmacokinetics of intramuscularly administered aminosidine in healthy subjects.

1997 ◽  
Vol 41 (5) ◽  
pp. 982-986 ◽  
Author(s):  
T P Kanyok ◽  
A D Killian ◽  
K A Rodvold ◽  
L H Danziger
Keyword(s):  
Healthy Subjects ◽  
Randomized Clinical Trials ◽  
Elimination Rate ◽  
Pharmacokinetic Parameters ◽  
Multiple Drug ◽  
Time Data ◽  
Time Curve ◽  
First Order ◽  
Significant Difference

Aminosidine is an older, broad-spectrum aminoglycoside antibiotic that has been shown to be effective in in vitro and animal models against multiple-drug-resistant tuberculosis and the Mycobacterium avium complex. The objective of this randomized, parallel trial was to characterize the single-dose pharmacokinetics of aminosidine sulfate in healthy subjects (eight males, eight females). Sixteen adults (mean [+/- standard deviation] age, 27.6 +/- 5.6 years) were randomly allocated to receive a single, intramuscular aminosidine sulfate injection at a dose of 12 or 15 mg/kg of body weight. Serial plasma and urine samples were collected over a 24-h period and used to determine aminosidine concentrations by high-performance liquid chromatographic assay. A one-compartment model with first-order input, first-order output, and a lag time (Tlag) and with a weighting factor of 1/y2 best described the data. Compartmental and noncompartmental pharmacokinetic parameters were estimated with the microcomputer program WinNonlin. One subject was not included (15-mg/kg group) because of the lack of sampling time data. On average, subjects attained peak concentrations of 22.4 +/- 3.2 microg/ml at 1.34 +/- 0.45 h. All subjects had plasma aminosidine concentrations below 2 microg/ml at 12 h, and all but two subjects (one in each dosing group) had undetectable plasma aminosidine concentrations at 24 h. The dose-adjusted area under the concentration-time curve from 0 h to infinity of aminosidine was identical for the 12- and 15-mg/kg groups (9.29 +/- 1.5 versus 9.29 +/- 2.2 microg x h/ml per mg/kg; P = 0.998). Similarly, no significant differences (P > 0.05) were observed between dosing groups for peak aminosidine concentration in plasma, time to peak aminosidine concentration in plasma, Tlag, apparent clearance, renal clearance, elimination rate constant, and elimination half-life. A significant difference was observed for the volume of distribution (0.35 versus 0.41 liters/kg; P = 0.037) between the 12 and 15 mg/kg dosing groups. Now that comparable pharmacokinetic profiles between dosing groups have been demonstrated, therapeutic equivalency testing via in vitro pharmacokinetic and pharmacodynamic modelling and randomized clinical trials in humans should be conducted.

scholarly journals Ball-milling effect on Indonesian natural bentonite for manganese removal from acid mine drainage

2018 ◽  
Vol 156 ◽  
pp. 03046 ◽  
Author(s):  
Widyawanto Prastistho ◽  
Winarto Kurniawan ◽  
Hirofumi Hinode
Keyword(s):  
Particle Size ◽  
Acid Mine Drainage ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Mine Drainage ◽  
Nitrogen Adsorption ◽  
Exchange Capacity ◽  
Manganese Removal ◽  
Acid Mine ◽  
Adsorption Desorption

The influences of mechanical milling on Indonesian Natural Bentonite (INB) characteristics and manganese (Mn) removal from acid mine drainage (AMD) were investigated. The INB characteristics were observed by scanning electron microscope (SEM), X-ray diffraction (XRD), nitrogen adsorption-desorption for specific surface area (SSA) and microporosity measurement, cation exchange capacity (CEC) and particle size distribution (PSD) analyzer. Four minutes milling with frequency 20 Hz on INB caused morphological change which showed more crumbled and destructed particle, lost the (001) peak but still retained the (100) peak that indicated delamination of montmorillonite mineral without breaking the tetrahedral-octahedral-tetrahedral (T-O-T) structure, rose the CEC from 28.49 meq/100g to 35.51 meq/100g, increase in the SSA from 60.63 m2/g to 104.88 m2/g, significant increase in microporosity which described in the t plots and decrease in the mean particle size distribution peak from 49.28 μm to 38.84 μm. The effect of contact time and effect of adsorbent dosage on Mn sorption was studied. Both unmilled and milled samples reached equilibrium at 24 hours and the pH rose from 4 to 7 in first 30 minutes. The Mn removal percentage increased significantly after milling. Using Langmuir isotherm, the maximum adsorbed metals (qmax) also increased from 0.570 to 4.219 mg/g.

Evolution structurale de la nacrite en fonction de la nature des molécules organiques intercalees

2000 ◽  
Vol 33 (6) ◽  
pp. 1351-1359 ◽  
Author(s):  
A. Ben Haj Amara ◽  
H. Ben Rhaiem ◽  
A. Plançon
Keyword(s):  
Ir Spectroscopy ◽  
Hydrogen Bonds ◽  
Dimethyl Sulfoxide ◽  
Organic Molecules ◽  
Interlayer Space ◽  
X Ray Diffraction ◽  
X Ray ◽  
Intercalated Compounds ◽  
Xrd Study ◽  
Intercalation Process

Nacrite has been intercalated with two polar organic molecules: dimethyl sulfoxide (DMSO) andN-methylacetamide (NMA). The homogeneous nacrite complexes have been studied by X-ray diffraction (XRD) and infrared (IR) spectroscopy. The XRD study is based on a comparison between experimental and calculated patterns. The structures of the intercalated compounds have been determined, including the mutual positions of the layers after intercalation and the positions of the intercalated molecules in the interlayer space. It has been shown that the intercalation process causes not only a swelling of the interlayer space but also a shift in the mutual in-plane positions of the layers. This shift depends on the nature of the intercalated molecules and is related to their shape and the hydrogen bonds which are established with the surrounding surfaces. For a given molecule, the intercalation process is the same for the different polytypes of the kaolinite family. These XRD results are consistent with those of IR spectroscopy.

scholarly journals Regulation Mechanisms of Expression and Function of Organic Cation Transporter 1

2021 ◽  
Vol 11 ◽  
Author(s):  
Giuliano Ciarimboli
Keyword(s):  
Organic Cation ◽  
Basolateral Membrane ◽  
Organic Cation Transporter ◽  
Organic Cations ◽  
Regulatory Processes ◽  
Organic Cation Transporter 1 ◽  
Exogenous Origin ◽  
And Function

The organic cation transporter 1 (OCT1) belongs together with OCT2 and OCT3 to the solute carrier family 22 (SLC22). OCTs are involved in the movement of organic cations through the plasma membrane. In humans, OCT1 is mainly expressed in the sinusoidal membrane of hepatocytes, while in rodents, OCT1 is strongly represented also in the basolateral membrane of renal proximal tubule cells. Considering that organic cations of endogenous origin are important neurotransmitters and that those of exogenous origin are important drugs, these transporters have significant physiological and pharmacological implications. Because of the high expression of OCTs in excretory organs, their activity has the potential to significantly impact not only local but also systemic concentration of their substrates. Even though many aspects governing OCT function, interaction with substrates, and pharmacological role have been extensively investigated, less is known about regulation of OCTs. Possible mechanisms of regulation include genetic and epigenetic modifications, rapid regulation processes induced by kinases, regulation caused by protein–protein interaction, and long-term regulation induced by specific metabolic and pathological situations. In this mini-review, the known regulatory processes of OCT1 expression and function obtained from in vitro and in vivo studies are summarized. Further research should be addressed to integrate this knowledge to known aspects of OCT1 physiology and pharmacology.

Bisphenol A emission factors from industrial sources and elimination rates in a sewage treatment plant

2003 ◽  
Vol 47 (10) ◽  
pp. 117-122 ◽  
Author(s):  
M. Fuerhacker
Keyword(s):  
Bisphenol A ◽  
Estrogenic Activity ◽  
Animal Experiments ◽  
Elimination Rate ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Emission Factors ◽  
Point Sources ◽  
In Vitro Test

Bisphenol A (BPA) is widely used for the production of epoxy resins and polycarbonate plastics and is considered an endocrine disruptor. Special in vitro test systems and animal experiments showed a weak estrogenic activity. Aquatic wildlife especially could be endangered by waste water discharges. To manage possible risks arising from BPA emissions the major fluxes need to be investigated and the sources of the contamination of municipal treatment plants need to be determined. In this study, five major industrial point sources, two different household areas and the influent and effluent of the corresponding treatment plant (WWTP) were monitored simultaneously at a plant serving 120,000 population equivalents. A paper producing plant was the major BPA contributor to the influent load of the wastewater treatment plant. All the other emissions from point sources, including the two household areas, were considerably lower. The minimum elimination rate in the WTTP could be determined at 78% with an average of 89% of the total BPA-load. For a possible pollution-forecast, or for a comparison between different point sources, emission factors based on COD-emissions were calculated for industrial and household point sources at BPA/COD-ratios between 1.4 ×10−6-125×10−6 and 1.3×10−6-6.3×10−6, respectively.

scholarly journals Mineralogical and physico-chemical characterizations of clay from Keur Saër (Senegal)

Clay Minerals ◽  
2012 ◽  
Vol 47 (4) ◽  
pp. 499-511 ◽  
Author(s):  
A. Mbaye ◽  
C. A. K. Diop ◽  
B. Rhouta ◽  
J. M. Brendle ◽  
F. Senocq ◽  
...  
Keyword(s):  
Cation Exchange ◽  
Cation Exchange Capacity ◽  
Clay Fraction ◽  
Exchange Capacity ◽  
Raw Material ◽  
Basic Knowledge ◽  
Mineral Mixture ◽  
Fine Clay ◽  
Main Component ◽  
Adsorption Desorption

AbstractThere is interest in exploiting and developing natural resources, particularly deposits of natural clays. Senegal has several clay mineral deposits for which chemical and mineralogical compositions have been little studied. Some of these natural materials are nowadays used in pottery and ceramics. To extend applications, a better basic knowledge is required and, for this objective, the raw clay and separated <2 μm clay fraction from Keur Saër (Senegal) were subjected to chemical and mineralogical studies. Several techniques including X-ray diffraction (XRD), thermal analysis (TG-DTA), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), N2 adsorption-desorption isotherms, cation exchange capacity (CEC) measurements and solid state nuclear magnetic resonance (NMR) have been used to characterize the material. It was found that the raw clay and the separated clay fraction consist of a mineral mixture in which kaolinite is the main component. 29Si and 27Al MAS-NMR spectra show the presence of silicon atoms linked to three other silicon atoms via an oxygen atom and six coordinated Al atoms. Significant increases in the specific surface area and cation exchange capacity were observed on purification, reaching a maximum of about 73.2 m2g–1 and 9.5 meq/100 g for the separated fine clay fraction while the values for the raw material were around 28.9 m2g–1 and 7.3 meq/100 g.

Controlling Anticoagulation in Extracorporeal Blood Circuits (hemoperfusion)

1984 ◽  
Vol 7 (1) ◽  
pp. 11-21
Author(s):  
L. Mor ◽  
S. Sideman ◽  
M. Mihich ◽  
A. Tzipiniuk ◽  
S. Lupovich ◽  
...  
Keyword(s):  
Elimination Rate ◽  
Blood System ◽  
Heparin Infusion ◽  
Heparin Concentration ◽  
Extracorporeal Blood ◽  
Heparin Administration ◽  
Pre Treatment ◽  
Second Procedure

The study demonstrates that different individuals (monkeys) need different heparin doses so as to avoid either clotting or bleeding when an extracorporeal blood system is involved. The linear correlation between PT and WBPTT values enables to utilize the latter for monitoring the heparin level in the blood. One procedure is based on the application of the Gotch and Keen intravenous heparinization model in its steady state limit by utilizing the pre-treatment evaluation of k/S, the ratio of the elimination rate constant to the individual's sensitivity to heparin. A second procedure involves the direct heparinization of the extracorporeal system. The heparin infusion rate is monitored through the arterial WBPTT values after relating the individual's PT or WBPTT values to the in vitro heparin concentration in the blood. In vitro and in vivo study of the effect of hemoperfusion through a column containing anion exchange particles on the amount and rate of heparin administration indicates that only the in vivo results are meaningful. The sharp response of WBPTT to relatively small changes of citrate concentration in the blood precludes individual monitoring by WBPTT. Work on the advantage of utilizing heparin together with citrate is required.

scholarly journals A mechanistic examination of salting out in protein–polymer membrane interactions

2019 ◽  
Vol 116 (46) ◽  
pp. 22938-22945 ◽  
Author(s):  
Nicholas A. Moringo ◽  
Logan D. C. Bishop ◽  
Hao Shen ◽  
Anastasiia Misiura ◽  
Nicole C. Carrejo ◽  
...  
Keyword(s):  
Random Walks ◽  
Single Molecule ◽  
Conformational Changes ◽  
Salt Concentration ◽  
Stochastic Theory ◽  
Protein Separations ◽  
Salting Out ◽  
Peak Broadening ◽  
Continuous Time Random Walks ◽  
Adsorption Desorption

Developing a mechanistic understanding of protein dynamics and conformational changes at polymer interfaces is critical for a range of processes including industrial protein separations. Salting out is one example of a procedure that is ubiquitous in protein separations yet is optimized empirically because there is no mechanistic description of the underlying interactions that would allow predictive modeling. Here, we investigate peak narrowing in a model transferrin–nylon system under salting out conditions using a combination of single-molecule tracking and ensemble separations. Distinct surface transport modes and protein conformational changes at the negatively charged nylon interface are quantified as a function of salt concentration. Single-molecule kinetics relate macroscale improvements in chromatographic peak broadening with microscale distributions of surface interaction mechanisms such as continuous-time random walks and simple adsorption–desorption. Monte Carlo simulations underpinned by the stochastic theory of chromatography are performed using kinetic data extracted from single-molecule observations. Simulations agree with experiment, revealing a decrease in peak broadening as the salt concentration increases. The results suggest that chemical modifications to membranes that decrease the probability of surface random walks could reduce peak broadening in full-scale protein separations. More broadly, this work represents a proof of concept for combining single-molecule experiments and a mechanistic theory to improve costly and time-consuming empirical methods of optimization.

scholarly journals An In Vitro Evaluation of the Capacity of Local Tanzanian Crude Clay and Ash-Based Materials in Binding Aflatoxins in Solution

Toxins ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 510 ◽  
Author(s):  
Emmanuel Ayo ◽  
Athanasia Matemu ◽  
Germana Laswai ◽  
Martin Kimanya
Keyword(s):  
Cation Exchange ◽  
Adsorption Capacity ◽  
Cation Exchange Capacity ◽  
Volcanic Ash ◽  
Rice Husk Ash ◽  
Binding Capacity ◽  
Exchange Capacity ◽  
In Vitro Technique ◽  
Great Health

Aflatoxins in feeds cause great health hazards to animals, and thus eventually to humans as well. The potential of clays from Arusha (AC), Kilimanjaro (KC), the Coast (CC), and Morogoro (MC), as well as volcanic ash (VA) and rice husk ash (RA), were evaluated for their capacity to adsorb aflatoxins B1 (AFB1), B2 (AFB2), G1 (AFG1), and G2 (AFG2) relative to a commercial binder Mycobind® (R) using in vitro technique. On average, CC, VA, KC, MC, AC, RA, and R adsorbed 39.9%, 51.3%, 61.5%, 62.0%, 72.6%, 84.7%, and 98.1% of the total aflatoxins from solution, respectively. The capacity of AC and RA was statistically (p < 0.05) better in binding aflatoxins next to R. The adsorption capacity seemed to follow the trend of the cation exchange capacity (CEC) of these materials. The CEC (meq/100 g) of CC, MC, KC, VA, AC, RA, and R were 7.0, 15.4, 18.8, 25.4, 27.2, 27.2, and 38.9, respectively. On average 96.3%, 42.7%, 80.8%, and 32.1% of AFB1, AFB2, AFG1, and AFG2 were adsorbed, respectively. The binding capacity of the clays and ashes relative to Mycobind® was about 100% for AC and RA, 50% for KC, MC, and VA, and 33.3% for CC. The AC and RA seem to be promising resources in binding aflatoxins in solution.

scholarly journals A Novel Synthesis of Fe3O4@SiO2@Au@Porous SiO2 Structure for NIR Irradiation-Induced DOX Release and Cancer Treatment

Dose-Response ◽  
2020 ◽  
Vol 18 (1) ◽  
pp. 155932582090666
Author(s):  
Meng Yang ◽  
Wenhua Yang ◽  
Liang Chen ◽  
Mingjian Ding ◽  
Chenhao Li ◽  
...  
Keyword(s):  
Drug Delivery ◽  
Near Infrared ◽  
Drug Loading ◽  
Thermal Conversion ◽  
Au Nanoparticle ◽  
Cell Viability Assay ◽  
Viability Assay ◽  
Transmission Electron ◽  
Adsorption Desorption

Doxorubicin (DOX) alone or in combination has been widely used for numerous cancers, including breast, lung, bladder, and so on. In this article, a core/shell/shell structured Fe3O4@SiO2@Au@porous SiO2 particles for the drug delivery and release of DOX was demonstrated, with the aid of near-infrared irradiation. Fe3O4 was used to direct the transportation and delivery of the drug-loaded composite to the target tissues and organs under an external magnetic field, the first layer of SiO2 was used for Au nanoparticle attachment, Au acted as the agent for light–thermal conversion, and the porous SiO2 was used to load DOX. The morphology of the nanoparticles was studied by transmission electron microscopy, and the porous structure was characterized by N2 adsorption/desorption curves. The drug delivery system displayed high drug loading capacity, and the release behavior was largely impacted by the environmental pH. Furthermore, the cytotoxicity of Fe3O4@SiO2@Au@porous SiO2 and DOX loaded Fe3O4@SiO2@Au@porous SiO2 was studied through in vitro 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide cell viability assay.

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