Biophysical Assessment and Impact of Catalyst on the Properties of Polyurethane Drug Carriers

The metal complexes and amine compounds are the most frequent categories of catalysts used in polyurethanes synthesis. Unfortunately, all auxiliary substances added to a synthesis increase the toxicological risk of final products used in a therapy. In the present study, polyether-urethane (PU) microstructures with and without catalyst were obtained. These structures were characterized by the measurement of samples� pH, of their size and stability, were obtained and the skin irritation potential. The results show that samples with a neutral pH, PU microstructures with sizes between 120 and 165 nm and with a medium stability. It was found that the microstructures from syntheses with catalyst present increased values of skin irritation.

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Radiation preparation of drug carriers for dexamethasone and tegafur based on poly(n-isopropylacrylamide) hydrogels

Nuclear Science and Technology ◽

10.53747/jnst.v5i1.184 ◽

2015 ◽

Vol 5 (1) ◽

pp. 39-45

Author(s):

Dang Sang Hoang ◽

Van Binh Nguyen ◽

Bang Diep Tran ◽

Thi Thom Nguyen ◽

Phuong Thao Hoang ◽

...

Keyword(s):

Skin Irritation ◽

In Vitro Release ◽

Drug Carriers ◽

Solution Temperature ◽

Critical Solution Temperature ◽

Human Body Temperature ◽

Drug Incorporation ◽

Water Swelling ◽

Vitro Release

Poly(N-isopropylacrylamide) (PNIPAM) based hydrogels with the lower critical solution temperature (LCST) near the human body-temperature have been obtained from 10% solutions of N-isopropylacrylamide (NIPA) and N,N’-dimethyl acrylamide(DMA) mixture of 90:10 and 85:15 (w/w) by radiation copolymerization and crosslinking using a gamma Co-60 source at a dose of 20 kGy. Water swelling behaviour of the resulting hydrogels was much dependent on the initial ratio of NIPA and DMA. The hydrogels of 85:15 NIPA/DMA was chosen for further investigation for the use as drug cariers.Two kinds of drug carriers were prepared by immerging the hydrogels in solutions containing dexamethasone and tegafur. Then the drug incorporation efficiencies and in-vitro release behaviors of the ingredient were analysed. Loading capacities of the hydrogels were about 48.6 and 95.7 mg per g of dried gel for dexamethasone and tegafur, respectively. The results also revealed that the presence of ions in simulated body fluid and solution temperature much affected to the release behaviors of hydrogels for both dexamethasone and tegafur. Release rates of the ingredients were quite fast for both drug models. These drug-loaded hydrogels were biocompatibility without skin irritation suggesting that they may be used as controlled release drug carriers.

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Interactions of Thymine and Uracil with Copper, Cobalt and Silver Ferrocyanides and the Implications in Chemical Evolution

Current Journal of Applied Science and Technology ◽

10.9734/cjast/2020/v39i830590 ◽

2020 ◽

pp. 31-43

Author(s):

Davendradat Doodnauth ◽

Brij Bhushan Tewari

Keyword(s):

Nucleic Acid ◽

Metal Complexes ◽

Chemical Evolution ◽

Uv Absorbance ◽

Nucleic Acid Bases ◽

Acid Base ◽

Neutral Ph ◽

Nucleic Acid Base ◽

Nucleic Bases ◽

Ph Range

Effects on pH based adsorption of nucleic acid bases (thymine and uracil) at two different concentrations 1 x 10-4 M and 1 x 10-5 M on copper, cobalt and silver ferrocyanides were studied over a pH range (1.0 – 10.0) at temperature 30±1ºC. The progress of adsorption was followed spectrophotometrically by measuring the UV absorbance of the nucleic acid base solutions at their corresponding max. Maximum adsorptions were found at neutral pH for both thymine and uracil. Effects of concentrations on adsorption of thymine and uracil on copper, cobalt and silver ferrocyanides were studied in a concentration range 10-4 – 10-5 M at neutral pH 7.0 ± 0.1 and at temperature 30±1°C. The interaction followed the Langmuir type of adsorption in general in the concentration range of 10-4 to 10-5 M of thymine and uracil solution. The uptake of nucleic bases on metal ferrocyanides followed the order of CuFc > AgFc > CoFc for the adsorption of thymine and CuFc > CoFc > AgFc for the adsorption of uracil. Effects of the presence of salts on the adsorption of thymine and uracil on metal ferrocyanides also had been studied. The insoluble metal ferrocyanides’ interaction with biomolecules must have either formed metal complexes or could have enhanced the formation of biopolymers in fluctuating environment.

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Review of aminopolycarboxylic acids–based metal complexes application to water and wastewater treatment by (photo-)Fenton process at neutral pH

Current Opinion in Green and Sustainable Chemistry ◽

10.1016/j.cogsc.2021.100451 ◽

2021 ◽

Vol 28 ◽

pp. 100451 ◽

Cited By ~ 1

Author(s):

Prisco Prete ◽

Antonino Fiorentino ◽

Luigi Rizzo ◽

Antonio Proto ◽

Raffaele Cucciniello

Keyword(s):

Wastewater Treatment ◽

Metal Complexes ◽

Fenton Process ◽

Water And Wastewater Treatment ◽

Neutral Ph ◽

Aminopolycarboxylic Acids ◽

Water And Wastewater

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Mechanism of Anticancer Action of Novel Imidazole Platinum(II) Complex Conjugated with G2 PAMAM-OH Dendrimer in Breast Cancer Cells

International Journal of Molecular Sciences ◽

10.3390/ijms22115581 ◽

2021 ◽

Vol 22 (11) ◽

pp. 5581

Author(s):

Robert Czarnomysy ◽

Anna Muszyńska ◽

Jakub Rok ◽

Zuzanna Rzepka ◽

Krzysztof Bielawski

Keyword(s):

Breast Cancer ◽

Drug Resistance ◽

Metal Complexes ◽

Cancer Cells ◽

Breast Cancer Cells ◽

Drug Carriers ◽

Aqueous Environment ◽

Dependent Manner ◽

Mtor Inhibition ◽

Pathway Activation

Transition metal coordination compounds play an important role in the treatment of neoplastic diseases. However, due to their low selectivity and bioavailability, as well as the frequently occurring phenomenon of drug resistance, new chemical compounds that could overcome these phenomena are still being sought. The solution seems to be the synthesis of new metal complexes conjugated with drug carriers, e.g., dendrimers. Numerous literature data have shown that dendrimers improve the bioavailability of the obtained metal complexes, solving the problem of their poor solubility and stability in an aqueous environment and also breaking down inborn and acquired drug resistance. Therefore, the aim of this study was to synthesize a novel imidazole platinum(II) complex conjugated with and without the second-generation PAMAM dendrimer (PtMet2–PAMAM and PtMet2, respectively) and to evaluate its antitumor activity. Cell viability studies indicated that PtMet2–PAMAM exhibited higher cytotoxic activity than PtMet2 in MCF-7 and MDA-MB-231 breast cancer cells at relatively low concentrations. Moreover, our results indicated that PtMet2–PAMAM exerted antiproliferative effects in a zebrafish embryo model. Treatment with PtMet2–PAMAM substantially increased apoptosis in a dose-dependent manner via caspase-9 (intrinsic pathway) and caspase-8 (extrinsic pathway) activation along with pro-apoptotic protein expression modulation. Additionally, we showed that apoptosis can be induced by activating POX, which induces ROS production. Furthermore, our results also clearly showed that the tested compounds trigger autophagy through p38 pathway activation and increase Beclin-1, LC3, AMPK, and mTOR inhibition. The high pro-apoptotic activity and the ability to activate autophagy by the imidazole platinum(II) complex conjugated with a dendrimer may be due to its demonstrated ability to reverse multidrug resistance (MDR) and thereby increase cellular accumulation in breast cancer cells.

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Examination of Rabbit Fc Crystals

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100100445 ◽

1968 ◽

Vol 26 ◽

pp. 140-141

Author(s):

J. P. Robinson ◽

P. G. Lenhert

Keyword(s):

Molecular Weight ◽

Flat Plate ◽

Phosphate Buffer ◽

Asymmetric Unit ◽

X Ray Diffraction ◽

X Ray ◽

Neutral Ph ◽

Small Crystals ◽

Carbon Coated ◽

Diffraction Patterns

Crystallographic studies of rabbit Fc using X-ray diffraction patterns were recently reported. The unit cell constants were reported to be a = 69. 2 A°, b = 73. 1 A°, c = 60. 6 A°, B = 104° 30', space group P21, monoclinic, volume of asymmetric unit V = 148, 000 A°3. The molecular weight of the fragment was determined to be 55, 000 ± 2000 which is in agreement with earlier determinations by other methods.Fc crystals were formed in water or dilute phosphate buffer at neutral pH. The resulting crystal was a flat plate as previously described. Preparations of small crystals were negatively stained by mixing the suspension with equal volumes of 2% silicotungstate at neutral pH. A drop of the mixture was placed on a carbon coated grid and allowed to stand for a few minutes. The excess liquid was removed and the grid was immediately put in the microscope.

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Mechanochemical changes on cyclometalated Ir(iii) acyclic carbene complexes – design and tuning of luminescent mechanochromic transition metal complexes

Inorganic Chemistry Frontiers ◽

10.1039/c9qi01278h ◽

2020 ◽

Vol 7 (3) ◽

pp. 786-794 ◽

Cited By ~ 3

Author(s):

Jingqi Han ◽

Kin-Man Tang ◽

Shun-Cheung Cheng ◽

Chi-On Ng ◽

Yuen-Kiu Chun ◽

...

Keyword(s):

Transition Metal ◽

Metal Complexes ◽

Transition Metal Complexes ◽

Carbene Complexes ◽

New Class

A new class of luminescent cyclometalated Ir(iii) complexes with readily tunable mechanochromic properties derived from the mechanically induced trans-to-cis isomerization have been developed.

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