The voltammetric behaviour of Sulfadoxine (SDN) was studied at a glassy carbon electrode in 0.2 M phosphate buffer solutions using cyclic, differential-pulse (DPV) and square wave voltammetry (SWV). The dependence of the current on pH, concentration, and scan rate was investigated to optimize the experimental conditions for the determination of SDN. The oxidation process was shown to be diffusi...

The elucidation of the mechanism of photosynthetic electron transport and photosynthetic phosphorylation depends, in part, upon a knowledge of the intermediates in the photosynthetic electron transport chain and the sequence in which they act. Mutant strains of the unicellular green alga Chlamydomonas reinhardi that cannot carry out normal photosynthesis1 can aid in obtaining this knowledge. In...

The isolation of Clostridium beijerinckii mutants that are more tolerant of butanol than the wild-type offered the opportunity to investigate whether the membrane activities which are required for maintaining the transmembrane DeltapH (the difference in pH between the cellular interior and exterior) are sensitive targets of butanol toxicity. The DeltapH was measured by the accumulation of [14C]...

The steady-state kinetics of the reaction catalysed by the bloodstream form of Trypanosoma brucei were studied at pH 6.7. In the presence of 50 mM-potassium phosphate buffer, the apparent co-operativity with respect to fructose 6-phosphate and the non-linear relationship between initial velocity and enzyme concentration, which were found when the enzyme was assayed in 50 mM-imidazole buffer [Cr...

The aerosol survival of Escherichia coli JEPP, a particularly sensitive strain, has been studied in a nitrogen atmosphere (> 99.9 yo) when sprayed from suspension in solutions of sodium glutamate or glycerol, and collected into phosphate buffer with or without M-sucrose. The response caused by changes in relative humidity (RH) to 30% and I O O ~ ~ before collection was also examined, These two ...

Phosphate buffers are used in many ophthalmological preparations for adjustment of the pH. The use of eye medication containing a phosphate buffer in patients with pronounced damage to the corneal surface can result in corneal calcification as a result of precipitation of calcium phosphate. On the basis of individual case reports, ophthalmological preparations containing phosphate were subjecte...

levamizole hydrochloride (c11h12 n2 s.hcl) is a drug capable of being rapidly absorbed from the gastrointestinal tract and is also rapidly eliminated from plasma. it has a modulating effect on the immunesystem, and may be used in treatment of parasitic diseases and infections. because of its toxicity to liver and its rapid clearance from plasma, this drug must be formulated in such a way so as ...

PURPOSE Drug release profiles were established for ibuprofen encapsulated within several types of microspheres and a range of dissolution buffer media to study the effect these variables have in controlling the rate and extent of drug release. METHODS Fatty acid microspheres containing ibuprofen were prepared by a process previously developed and refined to produce microspheres of a known siz...

Fluorescein is a complex fluorophore that can exist in one or more of four different prototropic forms (cation, neutral, dianion, and monoanion) depending on pH. In the pH range 6-10, only the dianion and monanion forms are important. In a previous article, we showed by steady-state fluorescein measurements that an excited fluorescein molecule displays excited-state proton transfer reactions wh...