print.expirest_wisle: Print a summary of the what-if shelf life estimation (wisle)

Description

This is a method for the function print() for objects of class ‘expirest_wisle’.

Usage

# S3 method for expirest_wisle
print(x, ...)

Value

The ‘expirest_wisle’ object passed to the x parameter is returned invisibly.

Arguments

x: An object of class ‘expirest_wisle’ returned by the expirest_wisle() function.
...: Further arguments passed to or from other methods or arguments that can be passed down to the formatC() function.

Details

The function expirest_wisle() estimates the expiry for the specified release and specification limit following the ARGPM guidance “Stability testing for prescription medicines”. By default, batch poolability is checked as recommended by the ICH Q1E guideline at a significance level of 0.25. Other levels can be used, although not recommended, by changing the default of the alpha_pool parameter. Three possible models may be appropriate, i.e.

a common intercept / common slope model (cics),
a different intercept / common slope model (dics) or
a different intercept / different slope model (dids).

The worst case intercept is the intercept of the batch whose confidence limit is the first crossing the acceptance limit. As in case of the cics model type all batches have a common intercept and a common confidence interval, all batches can be regarded as equally worst case. In case of the dids model type, shelf life estimation is done using the models obtained from fitting the data of each batch individually. In addition to the shelf life estimated according to the ARGPM also the estimate according to ICH Q1E is shown.

Examples

Run this code

# Potency stability data (in % of label claim (LC)) of five batches of a drug
# product obtained over a 24 months period:
str(exp1)

# 'data.frame':	53 obs. of  3 variables:
# $ Batch  : Factor w/ 6 levels "b2","b3","b4",..: 1 1 1 1 1 1 1 1 1 1 ...
# $ Month  : num  0 1 3 3 6 6 12 12 24 24 ...
# $ Potency: num  101 101.3 99.8 99.2 99.5 ...

# Fit models of different type
res1 <-
  expirest_wisle(data = exp1[exp1$Batch %in% c("b2", "b5", "b7"), ],
                 response_vbl = "Potency", time_vbl = "Month",
                 batch_vbl = "Batch", rl = 98, rl_sf = 3, sl = 95,
                 sl_sf = 3, srch_range = c(0, 500))

res2 <-
  expirest_wisle(data = exp1[exp1$Batch %in% c("b3", "b4", "b5"), ],
                 response_vbl = "Potency", time_vbl = "Month",
                 batch_vbl = "Batch", rl = 98, rl_sf = 3, sl = 95,
                 sl_sf = 3, srch_range = c(0, 500))
res3 <-
  expirest_wisle(data = exp1[exp1$Batch %in% c("b4", "b5", "b8"), ],
                 response_vbl = "Potency", time_vbl = "Month",
                 batch_vbl = "Batch", rl = 98, rl_sf = 3, sl = 95,
                 sl_sf = 3, srch_range = c(0, 500))

res1
# Summary of shelf life estimation following the ARGPM
# guidance "Stability testing for prescription medicines"
#
# The best model accepted at a significance level of 0.25 has
# Common intercepts and Common slopes (acronym: cics).
#
# Worst case intercept(s): 100.5669
# Worst case batch(es): NA
#
# Estimated shelf life (lives) for cics model:
#      SL RL    wisle    osle
# cics 95 98 14.07398 26.2241
#
# Abbreviations:
#   ARGPM: Australian Regulatory Guidelines for Prescription Medicines;
#   ICH: International Council for Harmonisation; osle: Ordinary shelf life
#   estimation (i.e. following the ICH guidance); RL: Release Limit; SL:
#   Specification Limit; wisle: What-if (approach for) shelf life estimation
#   (i.e. following ARGPM guidance).

res2
# Summary of shelf life estimation following the ARGPM
# guidance "Stability testing for prescription medicines"
#
# The best model accepted at a significance level of 0.25 has
# Different intercepts and Common slopes (acronym: dics).
#
# Worst case intercept(s):   100.82
# Worst case batch(es): b5
#
# Estimated shelf life (lives) for dics model:
#      SL RL    wisle     osle
# cics 95 98 11.40993 23.60194
#
# Abbreviations:
#   ARGPM: Australian Regulatory Guidelines for Prescription Medicines;
#   ICH: International Council for Harmonisation; osle: Ordinary shelf life
#   estimation (i.e. following the ICH guidance); RL: Release Limit; SL:
#   Specification Limit; wisle: What-if (approach for) shelf life estimation
#   (i.e. following ARGPM guidance).

res3
# Summary of shelf life estimation following the ARGPM
# guidance "Stability testing for prescription medicines"
#
# The best model accepted at a significance level of 0.25 has
# Different intercepts and Different slopes (acronym: dids).
#
# Worst case intercept(s): 101.2594
# Worst case batch(es): b8
#
# Estimated shelf life (lives) for dids model:
#      SL RL    wisle     osle
# cics 95 98 7.619661 15.96453
#
# Abbreviations:
#   ARGPM: Australian Regulatory Guidelines for Prescription Medicines;
#   ICH: International Council for Harmonisation; osle: Ordinary shelf life
#   estimation (i.e. following the ICH guidance); RL: Release Limit; SL:
#   Specification Limit; wisle: What-if (approach for) shelf life estimation
#   (i.e. following ARGPM guidance).