An important factor in the performance of a pharmaceutical product is how fast the product dissolves in vivo (in the body). This is measured by a dissolution test, which yields the percentage of the label strength (%LS) released after certain elapsed times. Laboratory tests of this type are conducted in vessels that simulate the action of the stomach. Display 9.73 shows %LS at certain time intervals for an analgesic (painkiller) tested in laboratories in New Jersey and Puerto Rico. Time is measured in minutes.
a. Use a 90% confidence interval to estimate the difference in mean %LS at 40 minutes for New Jersey compared to Puerto Rico.
Â b. Use a 90% confidence interval to estimate the difference in mean %LS at 60 minutes for New Jersey compared to Puerto Rico.
c. good manufacturing practices call for â€œequivalence limitsâ€ of 15 percentage points for dissolution percentages below 90% and 7 percentage points for dissolution percentages above 90%. That is, if the 90% confidence interval for the mean difference is within the equivalence limits (within an interval from âˆ’ 15% to + 15% for the lower percentages), then the two sets of results are accepted as equivalent. Will the results in parts a and b be accepted as equivalent at 40 minutes? At 60 minutes?