Special solvents acceptable concentration

One approach to the study of solubility is to evaluate the time dependence of the solubilization process, such as is conducted in the dissolution testing of dosage forms [70], In this work, the amount of drug substance that becomes dissolved per unit time under standard conditions is followed. Within the accepted model for pharmaceutical dissolution, the rate-limiting step is the transport of solute away from the interfacial layer at the dissolving solid into the bulk solution. To measure the intrinsic dissolution rate of a drug, the compound is normally compressed into a special die to a condition of zero porosity. The system is immersed into the solvent reservoir, and the concentration monitored as a function of time. Use of this procedure yields a dissolution rate parameter that is intrinsic to the compound under study and that is considered an important parameter in the preformulation process. A critical evaluation of the intrinsic dissolution methodology and interpretation is available [71]. 

These substances cannot be regarded as Bronsted bases in the normal sense of simple proton acceptors, since there is no evidence for the existence, under the experimental conditions in which the above ionizations are observed, of the conjugate acids (C6H5)3COH2 and H2N03. It might seem desirable to have a special name for such bases, but no reasonable name has been suggested. If, however, one accepts the solvent-system definition of a base as a species that increases the concentration of the characteristic anion of a solvent, no new name is needed. 

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