In Vitro Alternative Methods for the Assessment of Dermal Irritation and Inflammation
David W. Hobson in Dermal and Ocular Toxicology, 2020
Problems with serum protein precipitation have been reported using the acidic isopropanol solution as described above.39 This problem can be circumvented by changing the formazan product solubilization solution to one that includes sodium dodecyl sulfate (SDS).39,44 Modifications to the method as described by Hansen and co-workers are reported to decrease assay variability and to increase assay sensitivity.44 These modifications include the following: Add 25 μl of the 5 mg/ml MTT stock per 100 μl of medium instead of 10 μl.Replace the acidic isopropanol with an SDS-N,N-dimethyl formamide (DMF) mixture. The mixture is prepared by dissolving a 20% w/v solution of SDS in a 50% DMF-deionized water solution. The pH of the resulting solution is adjusted to 4.7 by the addition of 2.5% of 80% acetic acid and 2.5%of 1 N hydrochloric acid.After a 2-h 37°C incubation with MTT, 100 μl of the acidified SDS-DMF solution is added. The plates are then incubated overnight at 37°C and the optical densities at 570 nm determined. This procedure does not require mixing before measuring OD.
In-Vitro Antidermatophytic Bioactivity of Peel Extracts of Red Banana (Musa Acuminate) and Common Banana (Musa Paradisica)
Megh R. Goyal, Durgesh Nandini Chauhan in Assessment of Medicinal Plants for Human Health, 2020
The assessment was conducted by cup plate method. About 18 to 22 mL of PDA media was poured into the germ-free petri-plates and authors had to wait for the sample to solidify. Fungi was observed after five days of old maintained strain. And fungi strains were suspended in the brackish solution (0.85% NaCl) and accustomed for their turbidity at 0.5 McFarland’s standard. 1 mL of fungi strain was extended in excess of the medium via pure goblet purveyor. By means of Flame Sterilized Borer, obligatory concentration of in-sequence watered down extract (0.62 to 40 mg/mL) was supplemented to 20 μL in each well, whereas petri-plates were kept in the media for 1 h inside the refrigerant, and afterward were incubated at 37oC. Once incubated for 48 h, the petri-plates were studied further for the test. Width region of reticence was deliberated and articulated. Dimethyl formamide (DMF) was used as a negative indicator at the same time. The procedure was repeated for three times. The comparable process was followed for antidermophytic observations using NA media that was incubated at 37oC for 18 h.
Cellular Injury Associated with Organ Cryopreservation: Chemical Toxicity and Cooling Injury
John J. Lemasters, Constance Oliver in Cell Biology of Trauma, 2020
DMSO is not the only component of our cryoprotectant formulae, and the toxic effects of propylene glycol and formamide are also of interest. Virtually nothing is known of the toxic mechanisms of either solute, but Figure 6demonstrates that whatever the mechanism of toxicity of formamide may be, it can be completely reversed by the addition of DMSO. This protection appears specific to formamide since addition of DMSO to ethylene diamine (a highly toxic glass-forming agent) or to 2,3-butanediol39 exacerbated rather than reduced injury. Acetamide, which differs from formamide only by the addition of a methyl group, is dramatically less toxic than formamide, and in fact, a toxic level of acetamide has not yet been found. Addition of DMSO to acetamide produced a net increase in injury at total concentrations similar to those found to be protective in the case of formamide. Since DMSO and formamide do not hydrogen bond with one another at the temperature of exposure pertinent to Figure 6, neutralization of formamide toxicity by DMSO must be via actions of these agents on a common cell constituent or constituents that remain to be identified.
Layered double hydroxides - poloxamer 188 nanocomposites based on exfoliation reassembling for improved cellular uptake and controlled delivery of methotrexate
Published in Pharmaceutical Development and Technology, 2023
Liang Liang, Jin Ren, Jun Dai, Jianyun Liu, Lifang Zhang, Donglin Li, Chao Yang, Jingmou Yu
The proposed synthesis procedures of LDH-MTX and LDH-MTX-P188 nanocomposites was illustrated in Figure 1. LDH-MTX (Figure 1A), was prepared using co-precipitation combined hydrothermal method, in which MTX was loaded into the interlayer during coprecipitation of metal cations. LDH/MTX-P188 nanocomposite was synthesized via exfoliation reassembling method (Figure 1B). Simply, formamide was added to freeze-dried LDHs for swelling LDHs to finally form a monolayer through ultrasound. After that, MTX and P188 aqueous solution were successively added into it with ultrasound. During this process, the strong affinity between LDH monolayer and water was used to displace formamide for lamination reconstruction, in which drug molecules and P188 micelles were loaded into the interlayer. Subsequently, formamide was removed by repeatedly centrifugal and water washing. After water resuspension, it was aged at room temperature, which further making LDH fully contact with water for full lamination reconstruction, and finally obtaining LDH/MTX-P188 nanocomposites.
Nanoparticle-based chewable gels of praziquantel
Published in Pharmaceutical Development and Technology, 2023
M. Alejandra Gonzalez, M. Verónica Ramírez-Rigo, Noelia L. Gonzalez Vidal
The moisture content of the developed chewable gels was determined by Karl Fischer titration using a Metrohm Titrando 852 model, with associated software Tiamo version 2.2 (Methrom Schweiz, Zofingen, Switzerland). Approximately 0.1 g of chewable gel was dissolved in a solution consisting of anhydrous methanol and formamide, in a 1: 1 ratio. Formamide was used because it improves the solubility in methanol of polar substances and accelerates the extraction of water from solids at elevated temperatures. Molecular sieves of 0.3 nm were used for the conditioning of the cell, previously dried at 300 °C for 24 h. The reaction mixture was heated to 50 °C, to favour the dissolution of the sample, and then it was titrated with the titration reagent. The assay was performed fivefold.
Novel polysaccharide building hybrid nanoparticles: remodelling TAMs to target ERα-positive breast cancer
Published in Journal of Drug Targeting, 2022
Chunjing Guo, Yanguo Su, Bingjie Wang, Qiang Chen, Huimin Guo, Ming Kong, Daquan Chen
FA (110.28 mg, 0.25 mM) in 4 mL of anhydrous DMSO was stirred at 45 °C for 4 h with 1.5 equivalent EDCI and DMAP to form active esters. Then, Man (54.05 mg, 0.3 mM) in 2 mL of formamide was added into active ester solution, which was stirred at 55 °C for 48 h. Then, oHA (100.82 mg, 0.25 mM), 1.5 equivalent EDCI and HOBT in 3 mL of formamide were reacted at 50 °C for 4 h. Next, the FA-Man was added into oHA solution, and subsequently the mixed system was reacted at 60 °C for 48 h. After the end of the reaction, oHA-Man-FA solution was dialysed (2000 Da) for 24 h at 25 °C. In this step, unreacted FA, Man, FA-Man and organic solvents (small molecule compounds) would be removed through the dialysis membrane, but oHA-Man-FA (macromolecule compounds) would be trapped in the dialysis membrane. The solid oHA-Man-FA was obtained by lyophilisation.
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