[A] [B] [C] [D] [E] [F] [G] [H] [I] [J] [K] [L] [M] [N] [O] [P] [Q] [R] [S] [T] [U] [V] [W] [X] [Y] [Z]

**AIC**Akaike's Information Criterion can be used to determine the 'best' model from a number of alternatives.

AIC = N * ln(WSS) + 2 * M

where N is the number of data points with non-zero weight, WSS is the weighted sum of squares and M is the number of adjustable parameters. The same weighting scheme should be used for both models (AIC calculations). Ref: Yamaoka, K.,*et al.*, J. Pkin. Biopharm.,**6**, 165-175**Apical**surface of a cell is that surface exposed to the lumen**ATP**, adenosine triphosphate, provides the energy for most energy dependent cellular activities Ref**Basolateral**surface of a cell represents the sides and base, that is, other than the apical surface**Bioavailability**The rate and extent to which the active ingredient or active moiety is absorbed from a drug product and becomes available at the site of action.**Data point**Observed data. A data point measured by some analytical technique expressed in two dimensions, usually concentration and time. There may be measurement error in either or both dimensions although it is often assumed that the error in any time measurements is zero.**F-test**A statisitcal test use to determine if a particular hypothesis is true at a predetermined significance level. May be used to determine if a decrease in WSS observed when using a moe complex model is significant (usually at the 95% level).**Identifiability**This terms refers to the ability of the analyst to determine good values for model parameters using a particular set of data with a particular model under ideal conditions. Parameters may not be identifiable if there are insufficient data for the complexity of the proposed model or data from insufficient**k**Rate constant, see also kel, ka**ka**Absorption rate constant**ke**Excretion rate constant**kel**Elimination rate constant**km**Metabolism rate constant**knr**Non renal elimination rate constant**Linear plot**A graph paper plot where distances in the x and y-axis direction are proportional to the x or y-value.**Model**A mathematical representation of a process; specifically with regard to pharmacokinetics; drug and metabolite absorption, distribution, metabolism and excretion. Can be expresed a scheme or diagram, differential equation and usually integrated equations.**Parameter**A component of a model or equation that must be estimated graphically or by non-linear regression. Examples include V and kel.**Pharmaceutical Alternatives**Drug products are considered pharmaceutical alternatives if they contain the same therapeutic moiety, but are different salts, esters, or complexes of that moiety, or are different dosage forms or strengths.**Pharmaceutical Equivalents**Drug products are considered pharmaceutical equivalents if they contain the same active ingredient, are of the same dosage form, route of administration and are identical in strength or concentration**Semi-log plot**A graph paper plot where distances in the y-axis direction are proportional to the logarithm the value. Distances in the x-axis direction are proportional to the value.**Systematic deviation**A difference between the observed data and a calculated line that suggests that the line does not fully represent the data.**Therapeutic Equivalents**Drug products are considered to be therapeutic equivalents only if they are pharmaceutical equivalents and if they can be expected to have the same clinical effect and safety profile.**V**Apparent volume of distribution, see also Vd, Varea, Vss, Vbeta**Vd**Apparent volume of distribution, alternate notation**WSS**Weighted sum of squares or the weighted sum of the squared residuals.

WSS = SUM [Wt_{i}*(Obs_{i}-Calc_{i})^{2}]

It is a measure of the goodness of fit between a calculation line and the observed data. Lower values are better. Changing weighting schemes will change the value.**X-value**The independent term of an equation usually plotted on the horizontal axis. Commonly time but might be some other term.**Y-value**The dependent term of an equation usually plotted on the vertical axis. Commonly concentration but might be some other term.

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