Solid pharmaceutical dosage forms parameters

Hancock BC, ShambUn SL, Zografi G (1995) Molecular mobility of amorphous pharmaceutical solids below their glass-transition temperatures. Pharm Res 12(6) 799-806 Hancock BC, York P, Rowe RC (1997) The use of solubility parameters in pharmaceutical dosage form design. Int J Pharm 148(1) 1-21... 

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]. 

---