Dissolution testing is frequently used to determine the rate and extent at which a drug is released from a dosage form, and it plays many important roles throughout drug product development. However, the traditional dissolution approach often emphasizes its application in quality control testing and usually strives to obtain 100% drug release. As a result, dissolution methods are not necessarily biorelevant and meaningful application of traditional dissolution methods in the early phases of drug product development can be very limited. This article will describe the development of a biorelevant in vitro dissolution method using USP apparatus 4, biorelevant media, and real-time online UV analysis. Several case studies in the areas of formulation selection, lot-to-lot variability, and food effect will be presented to demonstrate the application of this method in early phase formulation development. This biorelevant dissolution method using USP apparatus 4 provides a valuable tool to predict certain aspects of the in vivo drug release. It can be used to facilitate the formulation development/selection for pharmacokinetic (PK) and clinical studies. It may also potentially be used to minimize the number of PK studies, and to aid in the design of more efficient PK and clinical studies.

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Slate has high alkali activity.When broken as aggregate, it produce high content of slate powder.In order to study the effect of slate powder on fly ash in suppressing alkali activity of slate aggregate and the possibility of making full use of the powder,we carried the experiment on rapid mortar bar method.The experimental results show that:1. When the content of slate powder is less than 15% , it has no adverse effect on fly ash in suppressing alkali activity of slate aggregate. When the content of slate powder is greater than 15%,it can increase the effect of suppression.2. For alkali-silica reaction,what really suppress it is the active SiO2 that comes from slate powder or fly ash.As long as the mineral admixture containing active SiO2 grinds fine to the fineness of cement particle, it can increase the effect of suppression on fly ash in suppressing alkali activity of slate aggregate, rather than reduces the suppressive effect.

The study on metakaolins inhibit effect to alkali-silica reaction (ASR) of slate aggregate by the way of accelerated mortar-bar test (AMBT),the results show that when the gel contains 15% metakaolin,the 14d expansion ratio is less than 0.03%,the inhibit reach the wear goal. But when we add the content of metakaolin, the expansion ratios are similar at every age.