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Bioequivalence drug absorption

BioavaUabUity and bioequivalence are related terms but they can be confused. Bioavailabihty as defined earlier is also known as absolute bioavailability and is simply the fraction of the administered dose that reaches the systemic circulation it is therefore defined only in terms of the extent of drug absorption. However, in the Committee for Proprietory Medicinal Products (CPMP) guideline for the investigation of bioavailability and bioequivalence, the former is defined as the rate and extent to which the active substance of therapeutic moiety is absorbed from a pharmaceutical form and becomes available at the site of action. The reason that bioavailability has been defined in this way is because rate, as well as extent, is important when comparing the bioavailability of two pharmaceutical forms of an active substance to determine whether they are bioequivalent. Bioequivalence and comparative bioavaUabUity are discussed later but absolute bioavailabihty will be described first. [Pg.183]

The last section of this chapter is devoted to the regulatory aspects of oral drug absorption and in particular to the biopharmaceutics classification system and the relevant FDA guideline. At the very end of the chapter, we mention the difference between randomness and chaotic behavior as sources of the variability encountered in bioavailability and bioequivalence studies. [Pg.114]

As a result, the way in which regulatory agencies are viewing bioavailability and bioequivalence issues has undergone change. In this section, we discuss the scientific basis of the regulatory aspects of oral drug absorption... [Pg.148]

Next to permeability, aqueous solubility is the most important biopharmaceutical property associated with oral drug absorption. These two properties have established the basis for a biopharmaceutical classification system (BCS) and have become the subject of an FDA guidance entitled Waiver of In Vivo Bioavailability and Bioequivalence Studies for Immediate-Release Solid Oral Dosage Forms Based on a... [Pg.374]

The measurement of the bioavailability and bioequivalence of drug dosage forms is commonplace. The numerous reasons for the increased use of such studies include rapid growth of the generic drug industry an increased awareness of the effect of dosage form on the rate and extent of drug absorption the development of more sensitive and reliable analytic methods to... [Pg.174]

Bioequivalent drug products are pharmaceutical equivalents whose bioavailability (i.e., rate and extent of systemic drug absorption) does not show a significant difference when administered at the same... [Pg.222]

Dressman JB, Yamada K. 1991. Animal models for oral drug absorption. In Pharmaceutical Bioequivalence, ed. P Welling, FL Welling, pp. 235-66. New York Dekker... [Pg.170]

The statistical evaluation of bioequivalence studies should be based on confidence interval estimation rather than hypothesis testing (Metzler, 1988, 1989 Westlake, 1988). The 90% confidence interval approach, using 1 —2a (where a = 0.05), should be applied to the individual parameters of interest (i.e. the pharmacokinetic terms that estimate the rate and extent of drug absorption) (Martinez Berson, 1998). Graphical presentation of the plasma concentrationtime curves for averaged data (test vs. reference product) can be misleading, as the curves may appear to be similar even for drug products that are not bioequivalent. [Pg.85]

Tozer, T.N. (1994) Bioequivalence data analysis Evaluating the metrics of rate and extent of drug absorption. Journal of Veterinary Pharmacology and Therapeutics, 17,105. [Pg.91]

In this chapter, we have discussed and emphasized the importance of the fundamental factors in BCS, solubility, and intestinal permeability for oral drug absorption. The main regulatory impact today is the use of BCS as a framework for identifying drugs for which in vitro dissolution testing could replace in vivo studies to determine bioequivalence. Extensions of this approach to cases other than IR formulations of... [Pg.552]

Figure 2.5 Stages in drug absorption from an extravascular administration site (stomach, small intestine, intramuscular injection). Only drug in solution is absorbed. If the rate of dissolution (K2) is less than the rate of absorption (K3) then the rate at which drug is released from the dosage form controls absorption. This permits modified or sustained-release formulations, but can also lead to bioequivalence problems. Figure 2.5 Stages in drug absorption from an extravascular administration site (stomach, small intestine, intramuscular injection). Only drug in solution is absorbed. If the rate of dissolution (K2) is less than the rate of absorption (K3) then the rate at which drug is released from the dosage form controls absorption. This permits modified or sustained-release formulations, but can also lead to bioequivalence problems.
Bioavailability and bioequivalence are related terms but they can be confused. Bioavailability as defined in Section 5.2.3.2 is also known as absolute bioavailability and is simply the fraction of the administered dose that reaches the systemic circulation it is therefore defined only in terms of the extent of drug absorption. However, in the CPMP guideline for... [Pg.225]

Dressman JB, Yamada K. Animal model for oral drug absorption. In WeUing, PG, Tse FLS, Dighe S, eds. Phaimaceutical Bioequivalence. New York Marcel Dekker, 1991 235-266. [Pg.327]

The kinetics of intestinal drug absorption, permeation enhancement, chemical moiety structure-permeability relationships, dissolution testing, in vitro/in vivo correlation, bioequivalence, and the development of novel polymeric materials are closely associated with the concept of Caco-2. As most drugs are known to absorb via intestines without using cellular pumps, passive permeability models... [Pg.150]


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