Bioequivalence and Bioavailability Forum

Calculation of time above MIC [🇷 for BE/BA]

posted by Aceto81 – Belgium, 2008-06-30 17:50 (6151 d 14:27 ago) – Posting: # 1988
Views: 35,981

Hi HS,

the time above MIC was calculated during the Steady State, which goes from 12 hours to 120 hours. That's why the results differs. (I was struggling with this part as well ).

Here the updated code:
time <- c(0.5, 1, 3, 5, 8, 12, 24, 36, 48, 60,
          72, 84, 96, 108, 120, 122, 124)
conc <- c(0.64, 0.7, 1.39, 1.35, 0.67, 1.48, 0.32, 2.08, 0.87, 0.93,
          1.09, 0.59, 1.01, 0.47, 0.99, 0.62, 0.13)
dat  <- data.frame(time, conc)

f <- function(dat, th) {
  under <- 0
  for (i in which(dat$conc < th)) {
      if (!is.na(dat$conc[i-1])) {
        y <- dat$conc[c(i-1,i)]
        x <- dat$time[c(i-1,i)]
        slope <- coef(lm(y~x))[2]
        under <- under + x[2]-x[1]-(th-y[1])/slope
      }
      if (!is.na(dat$conc[i+1])) {
        y <- dat$conc[c(i,i+1)]
        x <- dat$time[c(i,i+1)]
        slope <- coef(lm(y~x))[2]
        under <- under + (th-y[1])/slope
      }
    }
  return(under)
}

th    <- 0.517
first <- 12
last  <- 120
occupancy <- last-first - f(dat[dat$time >=first & dat$time <=last, ], th)
coverage  <- 100*occupancy/(last-first)
cat(" Time point interval:",first,"-",last,"\n",
    "Occupancy time:",occupancy,"\n",
    "Coverage:",coverage,"%\n")

Thanks for your valuable input

Ace

Complete thread:

• Calculation of time above MIC Aceto81 2008-06-26 16:31 [🇷 for BE/BA] 
  • Calculation of time above MIC Helmut 2008-06-26 18:58
    • Calculation of time above MIC Aceto81 2008-06-26 21:50
      • Calculation of time above MIC Helmut 2008-06-27 00:18
      • Calculation of time above MIC Helmut 2008-06-29 02:24
        • Calculation of time above MICAceto81 2008-06-30 15:50
          • Therapeutic Occupancy Time / MEC Helmut 2008-06-30 16:45
    • Time above MIC (WinNonlin 5.2.1) Helmut 2008-08-08 20:38
      • Time above MIC (WinNonlin 5.2.1) Aceto81 2008-08-12 09:56
        • Time above MIC (WinNonlin 5.2.1) Helmut 2008-08-12 12:32
          • Time above MIC (R function) Aceto81 2008-08-13 11:19
            • Time above MIC (R function) Helmut 2008-08-13 13:18
              • Time above MIC (R function) Aceto81 2008-08-13 15:35
          • Phoenix-WinNonlin 6.0 released 29 May 2009 SDavis 2009-06-04 10:55
            • Phoenix-WinNonlin 6.0 Helmut 2009-06-04 11:57
              • Phoenix-WinNonlin 6.0 - introductory webinars SDavis 2009-06-04 18:50
                • Phoenix-WinNonlin 6.0 - introductory webinars Helmut 2009-06-04 23:40
      • TimeLow Astea 2017-10-28 22:15
        • PHX/WNL 8.0 vs. previous releases Helmut 2017-10-28 23:20
          • PHX/WNL 8.0 vs. previous releases Astea 2017-10-28 23:49
        • Occupancy, Half Value Duration, Plateau Time in Phoenix/WinNonlin 8 Helmut 2017-10-30 13:18
          • Occupancy, Half Value Duration, Plateau Time in Phoenix/WinNonlin 8 Astea 2017-10-31 01:12
            • Intersections Helmut 2017-10-31 12:32
              • nobody needs it... Astea 2017-10-31 18:24