Availability of drug information on bioequivalence of generic products - Findings of graduate interns at a University Pharmacy

Abstract

Access to drug information (DI) needed to evaluate generic product bioequivalence was studied to identify problems with the current status of DI availability and encourage proper use of DI. Ten items were chosen from among the stock of branded products at the University Pharmacy, and five corresponding generics were selected for each item. Conditions of access to information on pharmacokinetic tests and dissolution tests were rated and the assigned ratings compared. In the case of pharmacokinetic parameters obtainable from makers of generic drugs, we also performed Welch's t-test to compare the difference between values reported for branded and generic products. From the standpoint of individual tests, the pharmacokinetic tests yielded higher scores on the whole than did the dissolution tests, and low scores were obtained for the half-life of blood drug concentration (T1/2). We observed a tendency for the adequacy of information to depend more upon the drug item itself than upon the nature of the test. The percentage of tests allowing for comparison with branded products varied from 0%-75% (average 49%). Parameter by parameter, the range of variation was from 35% of Tmax to 63% of Cmax. Factors precluding comparison included insufficient data on branded products, mismatch in assayed chemical species between branded and generic, mismatch between final sampling time in AUCt measurement, dosage inconsistency, and insufficient data on generic products. DI should be provided in a manner that facilitates comparison of information supplied by generic drug makers with data released by makers of branded products. © 2007 The Pharmaceutical Society of Japan.