Optical Property Evaluation of Next Generation Thermal Control Coatings

Next generation white thermal control coatings were developed via the Small Business Innovative Research program utilizing lithium silicate chemistry as a binder. Doping of the binder with additives yielded a powder that was plasma spray capable and that could be applied to light weight polymers and carbon-carbon composite surfaces. The plasma sprayed coating had acceptable beginning-of-life and end-of-live optical properties, as indicated by a successful 1.5 year exposure to the space environment in low Earth orbit. Recent studies also showed the coating to be durable to simulated space environments consisting of 1 keV and 10 keV electrons, 4.5 MeV electrons, and thermal cycling. Large scale deposition was demonstrated on a polymer matrix composite radiator panel, leading to the selection of the coating for use on the Gravity Recovery And Interior Laboratory (GRAIL) mission

Synthesis and biological evaluation of bile acid dimers linked with 1,2,3-triazole and bis-β-lactam

We report herein the synthesis and biological evaluation of bile acid dimers 11-18 linked through 1,2,3-triazole and bis-β-lactam. The dimers 11-18 were synthesized using 1,3-dipolar cycloaddition reaction of diazido bis-β-lactams 3, 4 and terminal alkynes 7-10 derived from cholic acid/deoxycholic acid in the presence of Cu(I) catalyst (click chemistry). These novel molecules were evaluated in vitro for their antifungal and antibacterial activity. Most of the compounds exhibited significant antifungal as well as antibacterial activity against all the tested fungal and bacterial strains. Moreover, their in vitro cytotoxicities towards HEK-293 and MCF-7cells were also established

Synthesis of chimeric tetrapeptide-linked cholic acid derivatives: impending synergistic agents

Tetrapeptides derived from glycine and β-alanine were hooked at the C-3β position of the modified cholic acid to realize novel linear tetrapeptide-linked cholic acid derivatives. All the synthesized compounds were tested against a wide variety of microorganisms (Gram-negative bacteria, Gram-positive bacteria and fungi) and their cytotoxicity was evaluated against human embryonic kidney (HEK293) and human mammary adenocarcinoma (MCF-7) cell lines. While relatively inactive by themselves, these compounds interact synergistically with antibiotics such as fluconazole and erythromycin to inhibit growth of fungi and bacteria, respectively, at 1-24 μg/mL. The synergistic effect shown by our novel compounds is due to their inherent amphiphilicity. The fractional inhibitory concentrations reported are comparable to those reported for Polymyxin B derivatives

Identification, Synthesis, and Strategy For Minimization of Potential Impurities Observed In Raltegravir Potassium Drug Substance

Multiple sources of anticipated degradation and process impurities of raltegravir potassium drug substance observed during the laboratory optimization and later during its bulk synthesis are described in this article. The impurities were monitored by UPLC, and their structures are tentatively assigned on the basis of fragmentation patterns in LC–MS and NMR spectroscopy. Most of the impurities are synthesized, and their assigned constitutions were confirmed by co-injection in UPLC. In addition to the formation, synthesis, and characterization, strategy for minimizing these impurities to the level accepted by ICH is also described. We feel that our study will be helpful to the generic industry for obtaining chemically pure raltegravir potassium

Identification, Synthesis, and Strategy For Minimization of Potential Impurities Observed In Raltegravir Potassium Drug Substance

Multiple sources of anticipated degradation and process impurities of raltegravir potassium drug substance observed during the laboratory optimization and later during its bulk synthesis are described in this article. The impurities were monitored by UPLC, and their structures are tentatively assigned on the basis of fragmentation patterns in LC–MS and NMR spectroscopy. Most of the impurities are synthesized, and their assigned constitutions were confirmed by co-injection in UPLC. In addition to the formation, synthesis, and characterization, strategy for minimizing these impurities to the level accepted by ICH is also described. We feel that our study will be helpful to the generic industry for obtaining chemically pure raltegravir potassium