Dissolution distinguished from

Childs et al. formulated crystalline complexes with a salt form of an API with carboxylic acids. The antidepressant, fluoxetine hydrochloride, was cocrystallized with benzoic acid, succinic acid, and fumaric acid where the chloride ion acts as a hydrogen bond acceptor for the carboxylic acid groups of the three ligands. Intrinsic dissolution studies were carried out at 10°C because at 25°C, the rates were so rapid that the dissolution rates of the cocrystals could not be distinguished from one another. The fumaric acid 2 1 complex had a similar dissolution rate to that of the crystalline fluoxetine hydrochloride, but the dissolution rate for the benzoic acid 1 1 complex was half that of fluoxetine hydrochloride. Fluoxetine hydrochloride succinic acid 2 1 complex had approximately three times higher dissolution rate, but the dissolution was so fast that an accurate value was difficult to measure. ... 

As already mentioned, natural zeolites may be classified as hydrothermal or sedimentary, in reference to processes which are not ever very clearly distinguishable from each other. Basically and very schematically, the main differences involve two parameters distance between the sites of glass dissolution and the sites of crystal deposition, which are usually far in the hydrothermal process and close in sedimentary process (also said diagenesis), and temperature, which is usually higher in the former than in the latter [34],... 

Several known systems dissolve cellulose (126-129). These systems range from solutions in protonic acids (e.g., 78% phosphoric acid) to metallic complexes (e.g., cuprammonium). All known methods for dissolving cellulose can be fit into four main categories (128) cellulose acting as abase, cellulose acting as an acid, cellulose complexes, and cellulose derivatives. The cellulose derivatives are distinguished from those discussed previously in that dissolution occurs simultaneously with derivative formation and the derivative produced can easily be regenerated (129). 

The mechanism for the Ni-MH battery is clearly distinguished from other batteries such as Ni-Cd, Ni-Zn, Ni-Fe, Pb-acid and Li batteries in which the dissolution and precipitation of the active materials such as Cd, Zn, Fe, Pb and Li occur on the electrodes during charge-discharge cycles, changing the electrolyte concentration and electrode morphology, for example for Ni-Cd ... 

Deaggregation of solid dosage form (e.g., tablet or capsule) into its primary particles is termed as disintegration, and is thereby distinguished from drug dissolution. But in... 

The above discussed electrochemical equilibrium and the related Nernst potential E with the same processes in opposite direction has to be distinguished from the situation when two different processes compensate each other at the rest or mixed or corrosion potential Er. Spontaneous iron dissolution with hydrogen evolution in an acidic electrolyte is an example. If no external current is applied, Fe + dissolution is compensated by H+ reduction, i.e., the anodic and cathodic processes compensate each other. A deviation from the rest potential E - Er = jr is called polarization. For jt > 0, the anodic Fe dissolution is faster and requires an external current. For ji< 0, the hydrogen evolution exceeds iron dissolution with a cathodic overall current. 

It is important to distinguish clearly between the surface area of a decomposing solid [i.e. aggregate external boundaries of both reactant and product(s)] measured by adsorption methods and the effective area of the active reaction interface which, in most systems, is an internal structure. The area of the contact zone is of fundamental significance in kinetic studies since its determination would allow the Arrhenius pre-exponential term to be expressed in dimensions of area"1 (as in catalysis). This parameter is, however, inaccessible to direct measurement. Estimates from microscopy cannot identify all those regions which participate in reaction or ascertain the effective roughness factor of observed interfaces. Preferential dissolution of either reactant or product in a suitable solvent prior to area measurement may result in sintering [286]. The problems of identify-... 

Numerous atmospheric species react with the Earth s surface, mostly in ways that are not yet chemically described. The dissolution and reaction of SO2 with the sea surface, with the aqueous phase inside of living organisms or with basic soils is one example. Removal of this sort from the atmosphere usually is called dry removal to distinguish it from removal by rain or snow. In this case, the removal flux is often empirically described by a deposition velocity,... 

It is important to distinguish between erosion and degradation. Erosion is mass loss from a bioerodible polymer and may be a consequence of polymer dissolution or degradation of the polymer backbone, followed by dissolution of the degradation products. Degradation typically occurs by hydrolysis of the polymer backbone, the kinetics of which is a function of the polymer chemistry. Thus, erosion is the sum of several elementary processes, one of which may be polymer degradation. 

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