In the following we use the methodology developed in this paper for the evaluation of the bioequivalence of two cream products. The dataset was provided by the authors of Quartier et al. (2019), who use the cutaneous bioequivalence method detailed in their paper. It contains \(17\) pairs of comparable porcine skin samples on which measurements of econazole nitrate deposition (an antifungal medication used to treat skin infections) were collected using two bioequivalent products. These measurements were then considered on the logarithmic scale and saved as an RData file called skin.
The results presented in Figure 4 of Boulaguiem et al. (2023) can be reproduced as follows:
library(cTOST)
data(skin)
# Empty plot
plot(1,1,pch="",axes=FALSE,xlab="",ylab="",main="",
ylim=c(min(unlist(skin)),log(4000)),xlim=c(0.75, 2.25))
# Plotting and linking the paired data points of each group
for(i in 1:nrow(skin)){
points(c(1,2),skin[i,],col=paste0(gray(0.1),50),pch=16)
segments(1,skin[i,1],2,skin[i,2],
col=paste0(gray(0.1),50))
}
axis(1, at = c(1,2), c("Reference", "Generic"),tick=FALSE)
axis(2, at = log(c(250,500,1000,2000,4000)), c(250,500,1000,2000,4000), las=2)
axis(2, at = mean(c(min(unlist(skin)),log(4000))), expression(paste("ECZ deposition (ng/cm"^2*")")),padj=-4.5, tick = FALSE)