MATLAB: AUC for Pharmacokinetic Study

aucSimBiologytrapezoidal

I have three supplements that I would like to compare (bioavailability). For each of the three, we will have whole bood, serum, and urine measurements done at timed intervals in a day. Supplements will be given orally and it will be a single dose (three different days for each).

I am exploring the best way to calculate area under the curve using trapezoidal rule, finding tmax, and cmax. I have explored Simbiology and the examples I have seen are far more complex than what I need. I will appreciate any help on getting this done. Thank you.

Best Answer

The simplest way to calculate AUC in MATLAB using the trapezoidal rule is probably to use the function trapz. Within SimBiology, these sorts of caculations are usually done as part of non-compartmental analysis. Would one of those approaches work for you?

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MATLAB: Do simfunctions support parameterized dosing

Yes, parameterized doses are supported with SimFunctions. However, you cannot change the type of parameterization after creating a SimFunction. In your example, you created a SimFunction with a dose that was not parameterized, so you cannot simulate it with a parameterized dose table.

To create a SimFunction that uses a parameterized dose, replace your input {'drug'} with a "template" dose object that is parameterized. For example, you can re-use your existing dose for this by changing the next-to-last line of code to the following:

simFunction = createSimFunction(model,{},{'drug'},dose);

MATLAB: How does Matlab Simbiology calculate pharmacokinetic (PK) non-compartmental (NCA) area under the curve (AUC)

Hi,

Some of the details of SimBiology's non-compartmental analysis (NCA) depend on the type of data and type of dose. However, the conceptual approach is similar, so I will explain below how SimBiology calculates the AUC for a single dose with an IV bolus dose.

First, SimBiology uses the linear trapezoidal rule to estimate the area under the time-concentration curve until the last concentration measurement. This is denoted as AUC_0_tz in the SimBiology desktop. If time is denoted as t and concentration as y, then the following formula is used:

AUC_0_tz = trapz(t,y);

Next, the final two concentration measurements are used to estimate the terminal rate constant, denoted as Lambda_z in the SimBiology desktop. This is calculated in log-space as follows:

Lambda_z = -((log(y(end)) - log(y(end-1)))/(t(end) - t(end-1)));

The extrapolated area under the curve (from t(end) to infinity) is calculated analytically by assuming exponential decay as y(end)/Lambda_z.

Combining all of these, you can see that the AUC is calculated as

AUC = trapz(t,y) - y(end)*(t(end) - t(end-1))/(log(y(end)) - log(y(end-1)))

Best Answer

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MATLAB: Do simfunctions support parameterized dosing

MATLAB: How does Matlab Simbiology calculate pharmacokinetic (PK) non-compartmental (NCA) area under the curve (AUC)

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