a b s t r a c tThermal stability, hydration and mechanical properties of thermally cross-linked sulfonated aromatic polymers (SAP) with high ionic exchange capacity (IEC) were measured and compared to untreated samples. The formation of cross-linking greatly stabilizes sulfonated polyphenylsulfone (SPPSU) in terms of thermal, mechanical, and hydrolytic degradation: it can resist in water even at a temperature of 145• C with improved mechanical properties, while TGA experiments demonstrate that SPPSU membranes are stable well above 200• C. Sulfonated polyethersulfone (SPES) membranes show, instead, a hydrolytic instability.
New methacrylate monomers, namely 4-methacryloyloxyphenyl-4 -fluorostyryl ketone and 4-methacryloyloxyphenyl-4 -ethylstyryl ketone comprising a free radical polymerizable group and a photocrosslinkable group, were synthesized by reacting the respective hydroxychalcones with methacryloyl chloride in the presence of triethylamine. The monomers were polymerized in the presence of ethyl methyl ketone (EMK) at 70• C using benzoyl peroxide as the initiator. The chemical structures were characterized using various spectroscopic techniques: ultraviolet, Fourier transform infrared, 1 H NMR and 13 C NMR. The thermal stability of the polymers was studied using thermogravimetric analysis in nitrogen atmosphere. Differential scanning calorimetry was used to determine the glass transition temperature of the homopolymers. Photocrosslinking of the synthesized homopolymers was investigated in solution. The two homopolymers were crosslinked within 10-15 min. After crosslinking, the homopolymers were insoluble in the same solvent.
A novel, economic, simple, precise and time-efficient reverse-phase high performance liquid chromatographic (RPHPLC) method has been established for the simultaneous assay determination of Dolutegravir, Lamivudine and Tenofovir Disoproxil fumarate in tablet formulation. This research paper presents the detailed method development strategy and the outcome of validation challenges. The RPHPLC method was developed using a 150 x 4.6mm, 5µm C18 column, with a gradient mode using 0.1% (v/v) trifluoroacetic acid buffer and methanol, the detection was performed at 260nm. The method was validated for specificity, precision, linearity, accuracy, robustness and can be used in quality control during manufacture and for assessment of the stability samples of Dolutegravir/Lamivudine/Tenofovir Disoproxil fumarate tablets. Total elution time was about 5 min and equilibration time of about 2 min which allows analysis of more than 100 samples per day. The method reported in this study is compatible to mass spectrometry and is thus extremely useful for stability studies.
A novel, accurate, specific, linear, precise and robust RP-HPLC method (stability indicating) has been developed and validated for the related substances (impurities) analysis of Dolutegravir, Lamivudine and Tenofovir Disoproxil Fumarate in tablet formulation. This research paper presents the developed method and the outcome of validation challenges. The RP-HPLC method was developed on a 250 x 4.6 mm, 5 µm, C18 column, with a gradient mode using combination of phosphate buffer and phosphoric acid in methanol and water as mobile phase, the detection was performed at 265nm and 235nm. The method was subjected to validation challenges of specificity, precision, linearity, accuracy, robustness and is demonstrated to be suitable for testing of stability samples.
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