In vitro dissolution methodologies that adequately capture the oral bioperformance of solid dosage forms are critical tools needed to aid formulation development. Such methodologies must encompass important physiological parameters and be designed with drug properties in mind. Two-phase dissolution apparatuses, which contain an aqueous phase in which the drug dissolves (representing the dissolu...

the partition coefficients (p-values) of certain new potential, stereoselective, reversible, long-acting local anesthetics have been determined in an n-octanol/ phosphate buffer system. these are derivatives of 2-phenoxyethyldialkylamine hydrochloride, and almost all of them are readily soluble in water. their aqueous solutions have shown different absorption maxima, and these have been used qu...

The effects of time, composition and history of preparation of the aqueous phase on the liquidliquid extraction of chromium(III) with Aliquat 336 from the aqueous alkaline solutions containing chlorides were studied. At time far from the equilibrium the yield and initial rate of the chromium(III) extraction depend on NaOH concentration, ionic strength of the aqueous phase and the way of its pre...

The most common stoichiometry of drug/cyclodextrin complexes is 1:1, i.e. one drug molecule forms a complex with one cyclodextrin molecule, and the most common method for stoichiometric determination during formulation studies is the phase-solubility method. However, in recent years it has becoming increasingly clear that solubilizing effects of cyclodextrins are frequently due to the formation...

This study presents a new approach that can stabilize effectively L-ascorbic acid in water-in-oil-in-water (w/o/w) double emulsions. Basically, the behavior of L-ascorbic acid in the aqueous phase was observed, considering its molecular deformation. Then, it was found that the stability determined in the aqueous phase by high-performance liquid chromatography (HPLC) showed that the collapse of ...

The chemical composition of nighttime urban fog has been investigated using a hybrid kinetic and equilibrium model. Extremely high acidity may be imparted to the droplets by condensation and growth on acidic condensation uclei or by in situ S(IV) oxidation. Important oxidants of S(IV) were found to be 02 as catalyzed by Fe(III) and Mn(II), H20:, and 03. Formation of hydroxymethanesulfonate ion ...

Oceans dominate emissions of dimethyl sulfide (DMS), the major natural sulfur source. DMS is important for the formation of non-sea salt sulfate (nss-SO42-) aerosols and secondary particulate matter over oceans and thus, significantly influence global climate. The mechanism of DMS oxidation has accordingly been investigated in several different model studies in the past. However, these studies ...

We describe the organic phase transfer of surfactant-stabilized rhodium nanoparticles previously synthesized in an aqueous solution of N,N-dimethyl-N-dodecyl-N-(2-hydroxyethyl)ammonium chloride (HEA12Cl); the addition of LiN(Tf)2 to the aqueous suspension of Rh-HEA12Cl transferred the hydrosol nanoparticles to an ionic liquid phase.

Mechanism of the absorption of drugs from oil in water emulsions was studied in the rat large intestine. Synthesized esters of fatty acids and phthalic acid-0.1% Polysorbate 80 was chosen as the emulsion system, the oil/water volume ratio was varied from 0 to 1, and the absorption from emulsions of sulfapyridine, salicylamide, and of acetanilide was investigated using in situ recirculation and ...