In a recent study (1) it was shown that cystine could be decomposed by boiling distilled water with the formation of cysteine, hydrogen sulfide, and elementary sulfur. The decomposition of cysteine under similar conditions should aid in a clearer explanation of the mechanisms involved in the breakdown of these two amino acids. The action of alkaline reagents on cysteine and its derivatives has ...

Colistimethate sodium, increasingly used to treat multidrug-resistant Gram-negative infections, spontaneously hydrolyzes to form colistin A (polymyxin E1) and B (polymyxin E2/B) when mixed with water. High levels of these active breakdown products at the time of administration have been associated with nephrotoxicity and even death. In this study, reconstituted colistimethate sodium was shown t...

The formulation scientist’s key goal is to achieve long-term stability of a drug compound. In the case of protein drugs, stabilization means not only maintaining the native chemical structure, but the native secondary and higher order structures necessary for biological activity (Cleland et al., 1993; Manning et al., 1989). Denaturation, as it is defined in this context, will be any non-native ...

In this paper electrical conductivity measurements and optical investigations takes place in AOT/ heptane/ (water or aqueous) systems. The water in oil system prepared with adding water in 50% by weight of AOT/ heptane solution.  In other systems instead of water, aqueous solutions of 1) zinc acetate and water 2) Potassium Hydroxide and water were used. In each phase, the trend of the electrica...

1. Many of the glass containers commonly used in the laboratory, and most of the glass ampules employed in marketing sterile solutions for hypodermic or intravenous medication, yield sufficient alkali on autoclaving, to change the reaction of distilled water from pH 6.0 to pH 9.0. 2. This increase in alkalinity is sufficient to render biologically inert and partially to decompose aqueous soluti...

For a NaI aqueous solution negative surface excess is inferred from the evolution of the ion photoemission signal as a function of the salt concentration. The experiments were performed using a 6μm diameter liquid microjet providing a free vacuum surface, which allows water molecules to evaporate without collisions, and hence enables the direct detection of photoelectrons originating from the l...

Coacervation is a phenomenon in which a colloidal dispersion separates into two immiscible liquid phases: a liquid rich in colloidal phase in equilibrium with another diluted liquid phase. Surfactant coacervation here refers to coacervation whose main components are surfactants with low molecular weights. Over the past two decades, surfactants have been greatly developed and studies on coacerva...

The pulse radiolysis of N(2)O saturated aqueous solutions of KSCN was studied under neutral pH conditions. The observed optical absorption spectrum of the SCN(*) radical in solution is more complex than previously reported, but it is in good agreement with that measured in the gas phase. Kinetic traces at 330 and 472 nm corresponding to SCN(*) and (SCN)(2)(*-), respectively, were fit using a Mo...

The effects of aqueous solvation on the photophysical pathways involving the S(1) excited state in cytosine have been studied with a mean-field QM/MM approach. Two main pathways with small barriers were found previously in isolated cytosine, using multireference configuration interaction (MRCI) methods, that facilitate radiationless decay to the ground state. These pathways are examined in solv...