Caffeine Concentration Predictorhttps://asan.shinyapps.io/caffCaffeine Concentration Predictoris open to everyone. We are happy to take your input. Please fork the repo, modify the codes and submit a pull request. https://github.com/shanmdphd/caff
This work is solely dependent on the interesting paper published in Eur J Pediatr in 2015.
- "Prediction of plasma caffeine concentrations in young adolescents following ingestion of caffeinated energy drinks: a Monte Carlo simulation." Eur J Pediatr. 2015 Dec;174(12):1671-8. doi: 10.1007/s00431-015-2581-x https://www.ncbi.nlm.nih.gov/pubmed/26113286
- "Clinical pharmacokinetics and pharmacodynamics: concepts and applications, 4th edition" Lippincott Williams & Wilkins. 2011. ISBN 978-0-7817-5009-7
The pharmacokinetic parameters from the paper were derived and used in the app as follows:
$$
\begin{split}
\begin{bmatrix}
\eta_1 \newline
\eta_2 \newline
\eta_3
\end{bmatrix}
& \sim MVN \bigg(
\begin{bmatrix}
0 \newline
0 \newline
0
\end{bmatrix}
,
\begin{bmatrix}
0.1599 & 6.095 \cdot 10^{-2} & 9.650 \cdot 10^{-2} \newline
6.095 \cdot 10^{-2} & 4.746 \cdot 10^{-2} & 1.359 \cdot 10^{-2} \newline
9.650 \cdot 10^{-2} & 1.359 \cdot 10^{-2} & 1.004
\end{bmatrix}
\bigg) \newline
\newline
CL\ (mg/L) & = 0.09792 \cdot W \cdot e^{\eta1} \newline
V\ (L) & = 0.7219 \cdot W \cdot e^{\eta2} \newline
k_a\ (1/hr) & = 4.268 \cdot e^{\eta3} \newline
\newline
k\ (1/hr) & = \frac{CL}{V} \newline
t_{1/2}\ (hr) & = \frac{0.693}{k} \newline
t_{max}\ (hr) & = \frac{ln(k_a) - ln(k)}{k_a - k} \newline
C_{max}\ (mg/L) & = \frac{Dose}{V} \cdot \frac{k_a}{k_a - k} \cdot (e^{-k \cdot t_{max}} - e^{-k_a \cdot t_{max}}) \newline
AUC\ (mg \cdot hr / L) & = \frac{Dose}{CL} \newline
\newline
C_{av,ss} & = \frac{Dose}{CL \cdot \tau} \newline
AI & = \frac{1}{1-e^{-k_e \cdot \tau}} \newline
\end{split}
$$
(Abbreviation:
- H. Wickham. ggplot2: Elegant Graphics for Data Analysis. Springer-Verlag New York, 2009.
- Winston Chang, Joe Cheng, JJ Allaire, Yihui Xie and Jonathan McPherson (2016). shiny: Web Application Framework for R. R package version 0.14.2. https://CRAN.R-project.org/package=shiny
- JJ Allaire, Jeffrey Horner, Vicent Marti and Natacha Porte (2015). markdown: 'Markdown' Rendering for R. R package version 0.7.7. https://CRAN.R-project.org/package=markdown
- Hadley Wickham and Romain Francois (2016). dplyr: A Grammar of Data Manipulation. R package version 0.5.0. https://CRAN.R-project.org/package=dplyr
