In vitro-in vivo correlation of four commercial brands of aspirin tablets marketed in Nigeria

The study investigated the possibility of developing an in vitro - in vivo correlation for four commercial brands of aspirin tablets using USPXXI rotating basket apparatus and urinary excretion profiles from eight human volunteers. Various dissolution and pharmacokinetic parameters were obtained for all the brands. Significant rank order correlations were observed between all the in vitro dissolution parameters such as percent dissolved at 30 min, dissolution rate constants (k) and time for 50% dissolution (DT(50%)) and all the in vivo bioavailability parameters such as cumulative amount excreted up to 8 h (E(8)), maximum excretion rate (dE/dt)(max) and time for maximum excretion rate (T(max)). However, no correlation could be established between the cumulative amount excreted up to 24 h (E(24)) and any of the in vitro dissolution parameters. Moreover, statistical analysis showed no significant inter-subject variation among the subjects that participated in the experiments.