Biopharmaceutics Classification System frameworks

Varma, M.V., et al. 2004. Biopharmaceutic classification system A scientific framework for pharmacokinetic optimization in drug research. Curr Drug Metab 5 375. 

Although there are some differences between the European [139] and the US guidance [137,138], e.g., the composition of the dissolution media, it should be pointed out that both recommend dissolution studies as quality assurance tests as well as for bioequivalence surrogate inference. The latter aspect is particularly well developed in the FDA guidance [138] in the framework of the biopharmaceutics classification system, which is treated in Section 6.6.1. 

Aqueous solubility of ionizable molecules at different pH values is an important characteristic because it indicates the potential substance behavior in the stomach and intestinal tract and its potential impact on bioavailability. Moreover, it also provides important information for formulation scientists to define the class of a drug substance in the Biopharmaceutics Classification System (BCS), a regulatory guidance for bioequivalence studies. The BCS is a scientific framework proposed by the FDA to classify drug substances based on their aqueous solubility and intestinal permeability and defines important parameters in the selection of drug candidates into development. According to the BCS, drug substances are classified as shown in Table 12-4. 

The Biopharmaceutics Classification System (BCS) was proposed in 1995 by Amidon et aU It is a scientific framework which divides APIs into four groups, according to their solubility and permeability properties. 

Quantitative Structure-Property Relationship Analysis of Drugs Pharmacokinetics Within the Framework of Biopharmaceutics Classification System Using Simplex Representation of Molecular Structure... 

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